Platinum Metals Review - Johnson Matthey Technology Review

VOLUME 51 NUMBER 4 OCTOBER 2007

Platinum Metals Review

www.platinummetalsreview.com E-ISSN 1471–0676

E-ISSN 1471–0676

PLATINUM METALS REVIEW A Quarterly Survey of Research on the Platinum Metals and of Developments in their Application in Industry www.platinummetalsreview.com

VOL. 51 OCTOBER 2007 NO. 4

Contents Enhancement of Industrial Hydroformylation Processes by the Adoption of Rhodium-Based Catalyst: Part II

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By Richard Tudor and Michael Ashley

Novel Chiral Chemistries Japan 2007

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A conference review by David J. Ager

“Recent Developments in the Organometallic Chemistry of N-Heterocyclic Carbenes”

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A journal synopsis by Robert H. Crabtree

Annealing Characteristics and Strain Resistance of 99.93 wt.% Platinum

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By Yu. N. Loginov, A. V. Yermakov, L. G. Grohovskaya and G. I. Studenok

40th Conference ‘Deutscher Katalytiker’

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A conference review by Thomas Ilkenhans

“Metal-catalysis in Industrial Organic Processes”

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A book review by Robin B. Bedford

Building a Thermodynamic Database for Platinum-Based Superalloys: Part II

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By A. Watson, R. Süss and L. A. Cornish

The 21st Santa Fe Symposium on Jewelry Manufacturing Technology

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A conference review by Christopher W. Corti

“Combinatorial and High-Throughput Discovery and Optimization of Catalysts and Materials”

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A selective book review by Kim Chandler, Ann Keep, Sue Ellis and Sarah Ball

Abstracts

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New Patents

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Indexes to Volume 51

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Communications should be addressed to: The Editor, Barry W. Copping, Platinum Metals Review, [email protected]; Johnson Matthey Public Limited Company, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.

DOI: 10.1595/147106707X238211

Enhancement of Industrial Hydroformylation Processes by the Adoption of Rhodium-Based Catalyst: Part II KEY IMPROVEMENTS TO RHODIUM PROCESS, AND USE IN NON-PROPYLENE APPLICATIONS By Richard Tudor* and Michael Ashley Davy Process Technology Ltd., 20 Eastbourne Terrace, London W2 6LE, U.K.; *E-mail: [email protected]

Part I of this article (1), which appeared in the July 2007 issue of Platinum Metals Review, described the substantial cost and technical benefits brought to the hydroformylation of propylene with carbon monoxide and hydrogen (an ‘oxo’ reaction) by replacing the previous high-pressure cobalt-catalysed technology with a low-pressure rhodium-based catalyst system (the LP OxoSM Process). The background to the rhodium process and its development to the point of first commercialisation were reviewed. This article (Part II) covers some of the improvements made to the LP OxoSM Process after the early plants started operation, and its uses in non-propylene applications.

The ‘Low Pressure Oxo’ process (LP OxoSM Process) was developed and then licensed to the oxo industry through a tripartite collaboration beginning in 1971. The principals were Johnson Matthey & Co. Ltd. (now Johnson Matthey PLC), The Power-Gas Corporation Ltd. (a former name of Davy Process Technology Ltd., now a subsidiary of Johnson Matthey PLC) and Union Carbide Corporation (now a subsidiary of The Dow Chemical Company). Using rhodium-based catalysis, the LP OxoSM Process offered such great economic advantages over the established cobalt-catalysed processes, as well as technical elegance, that many cobalt systems were replaced by brand new plants. In the thirty years or so since the LP OxoSM Process was first introduced, it has maintained its position as the world’s foremost oxo process, having undergone much improvement and refinement. About two thirds of the world’s butyraldehyde is now produced in LP OxoSM plants. Most LP OxoSM systems are licensed plants, nearly all of which have been built under licences granted by Davy Process Technology (2) working in cooperation with The Dow Chemical Company (3); the remainder are plants owned and operated by Dow’s Union Carbide subsidiary (4).

Platinum Metals Rev., 2007, 51, (4), 164–171

The first commercial plant to use the LP OxoSM Process was a unit built by Union Carbide at Ponce in Puerto Rico for producing 136,000 tonnes per annum of butyraldehydes. The Ponce plant started operation in 1976. By the end of 1982, Davy Process Technology had licensed and designed ten LP OxoSM plants that were built around the world. All these plants employed a homogeneous triphenylphosphine (TPP)-modified rhodium catalyst, and in situ gas stripping was adopted to separate the butyraldehyde product from the rhodium-containing catalyst solution which remained in the oxo reactor. (The flowscheme for an LP OxoSM plant employing this gas recycle principle is described in Part I (1).) Adopting gas recycle not only led to a simple and affordable process flowsheet, it also provided the best overall working regime for the catalyst, in terms of both loss prevention and deactivation, based on the ‘state of the art’ at the time.

From Gas to Liquid Recycle Once the gas recycle technology had been proven, and market interest in the LP OxoSM Process was intensifying, Union Carbide and Davy Process Technology turned their attention to a new

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flowsheet concept employing the ‘liquid recycle’ principle. This involved separating the reaction product from the catalyst solution in equipment outside the oxo reactor, using a sequence of vapour flashing (resulting from an abrupt pressure reduction) and vaporisation using a suitable external heat source. Reaction solution from the back-mixed reactor was continuously fed to this equipment, in which the greater part of the butyraldehyde and reaction byproducts present in the feed were separated from the rhodium-bearing catalyst solution, which was recycled to the reactor. The net rate of removal by external vaporisation of products and byproducts matched their rate of production in the reactor, so as to maintain a constant catalyst solution inventory. The liquid recycle flowsheet also included the means to recover and recycle dissolved reactants present in the separated product stream. Apart from these basic principles of liquid recycle, much attention had to be given to the operating conditions under which vaporisation of products would occur, particularly the duration for which catalyst would be exposed to a raised temperature outside the equable environment of the reactor. Earlier deactivation studies in the laboratory and the successful operation of the Ponce plant had given valuable insights in this regard. It had become evident that decomposition of the triphenylphosphine (TPP)-rhodium complex – a potential concern – should be avoidable. A proprietary vaporisation system design emerged from the efforts of specialist engineers working alongside the process developers. The overriding merit of the liquid recycle approach was that by decoupling the hydroformylation reaction step from the physical process of product/catalyst separation, it became possible to adopt operating conditions in the reactor to optimise the balance of production rate (or reaction ‘speed’), selectivity and (catalyst) stability – the ‘three Ss’. The technique adopted exemplified the challenge facing the developers and designers of commercial liquid phase homogeneous catalyst systems, that of balancing the ‘three Ss’ by imaginatively addressing the issue of product/catalyst separation. Here, decoupling reaction from separation would, for example, obviate the necessity to run the reactor at temperatures dictated by product stripping requirements.

Platinum Metals Rev., 2007, 51, (4)

The introduction of liquid recycle therefore provided the plant operator with more degrees of freedom to get the best performance from an oxo reaction system than hitherto had been possible. For Davy Process Technology and Union Carbide, it would open up new possibilities for the LP OxoSM Process in terms of catalyst selection and its application with olefins other than propylene. Another advantage of the liquid recycle approach was that the oxo reactor could be reduced in size. With gas recycle, it was necessary to allow a significant excess reaction volume, to accommodate expansion of the liquid phase by the entrainment of bubbles from a large gas flow. With no such gas flow required with liquid recycle, most of this volume allowance could be dispensed with. This was particularly significant for gas recycle plant operators who had decided to enlarge their production capacities. By converting their plants from gas to liquid recycle, they could almost double the production capacities of their existing oxo reactors. With oxo plants becoming larger in size, the adoption of liquid recycle resulted in designs of lower cost, mainly as a result of the elimination of the cycle compressor and the use of smaller reactors. Practically all LP OxoSM plants designed since the mid 1980s employ liquid recycle, to which several of the early gas recycle designs have also been converted. Plant operators welcome the added operating flexibility, enabling them to optimise reaction conditions to their production capacity and product mix requirements.

The Introduction of a BisphosphiteModified Rhodium Catalyst A continuing programme of investment by Davy Process Technology and Union Carbide in research and process development aimed at improving and refining the LP OxoSM Process, coupled with the substantial operating experience accumulated from Union Carbide’s own oxo plants and more than twenty plants built by others under licence, have, over the years, resulted in considerable improvements to the original process. The technical and commercial appeal of the LP OxoSM Process over competing processes has, if anything, increased. The discovery and successful use of catalyst reactivation

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(discussed in Part I (1)), and the process enhancements resulting from the move from gas to liquid recycle are just two examples of the improvements made. The quest for improvement has not been confined to the TPP-modified rhodium system. Today, several LP OxoSM plants are producing butyraldehyde using a more advanced bisphosphite-modified rhodium catalyst developed by Union Carbide. The chemical characteristics, intrinsic activity, stability and regioselectivity of this catalyst show marked differences from those of the TPP-modified catalyst still used in most operating plants. The challenge of recent years has been how best to capitalise on the excellence of some attributes of bisphosphite catalysts where it most counts, i.e. in terms of feedstock utilisation efficiency, selectivity to normal butyraldehyde, rhodium inventory and catalyst life. It had been known for many years before the introduction of bisphosphites that phosphite-modified rhodium catalysts are very reactive and show good regioselectivity (i.e. selectivity to the straight chain aldehyde) in comparison with phosphinemodified catalysts. Conventional phosphites, however, had been found to be unstable in the presence of aldehydes. This limitation was overcome through the development of bisphosphite ligands. The preparation, structural features and performance in hydroformylation by bisphosphites were discussed by Union Carbide’s David R. Bryant at the Royal Society of Chemistry Dalton Division’s Fourth International Conference on the Chemistry of the Platinum Group Metals in 1990 (5, 6). Then,

in 1992, at a meeting of the American Chemical Society (7), Dr Bryant discussed the new-found place for bisphosphite-modified rhodium catalysts, describing them as the fourth generation of oxo catalysts, following the first-generation unmodified cobalt, then phosphine modified cobalt, then phosphine-modified rhodium catalysts. Several Union Carbide patents (e.g. 8–10) disclosed a large number of bisphosphite-modified rhodium catalyst systems that are much more active than those based on TPP, with much higher selectivity to the linear aldehyde possible. Certain Union Carbide patents also gave methods for stabilising bisphosphite-modified catalysts. Preparing the bisphosphite ligands from substituted biphenols imparts the high degree of steric hindrance needed to achieve the good regioselectivity sought in some hydroformylation applications, for instance in the production of butyraldehydes. The molecular structure of TPP and a general representation of a bisphosphite are shown in Figure 1. The chemical nature of the group bridging the two phosphite groups has a crucial bearing on hydroformylation performance. The bridge could be specifically configured to encourage high normal to iso selectivity at an acceptable reaction rate by the appropriate choice of substituents X3, X4, Y3 and Y4 in Figure 1. It is thought that the bisphosphite ligand functions in a hydroformylation environment by doubly coordinating rhodium to form a bidentate complex. The favourable steric environment thus created around the rhodium is the likely cause of the high

Y3 X2 P

Y2

Y4

O

O

O

P Y1 Triphenylphosphine

O

Y5

O

Y6

P

O X1

X5

X4

X3

Bisphosphite

X6

Fig. 1 Structures of triphenylphosphine and bisphosphite ligands. For butyraldehyde production, high normal to iso selectivity at an acceptable reaction rate is encouraged by the appropriate choice of substituents X3, X4, Y3 and Y4


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regioselectivity mentioned above. Union Carbide found that with propylene, it was possible to select in the laboratory a suitable bisphosphite-modified rhodium catalyst that would show about 30 times the activity of a TPP-modified catalyst, while achieving extraordinarily high selectivity to normal butyraldehyde and using lower ligand concentrations. Since bisphosphite-liganded catalyst complexes were viewed as having great potential, Union Carbide had devoted a substantial R&D effort to resolving issues over their stability in commercial hydroformylation environments. Union Carbide were confident that they had found a way forward to the first commercial use of these catalysts. The successful adoption of the liquid recycle principle in many operating LP OxoSM plants by the early 1990s had opened the way to specifying a commercial propylene hydroformylation process incorporating a bisphosphite-modified catalyst that would offer much appeal over its TPP counterpart. On the basis of test work they had performed in the laboratory, Union Carbide believed that they had discovered how best to utilise and sustain the high activity of bisphosphite-modified catalyst in a commercial environment. The first commercial plant to use the catalyst system was built by Union Carbide at its petrochemical complex at St. Charles, Louisiana, U.S.A., for producing 136,000 tonnes per annum of butanol from propylene. Production started in 1995. In designing the plant, the concentration of rhodium in the catalyst was set at about one third of that for a TPP-modified catalyst system, and the operating temperature of the catalyst and the reaction pressure were reduced. Catalyst productivity, relating the rate of production to catalyst volume, was not altered drastically from that for which the TPP-modified catalyst plants had been designed. It was thought better to exploit improved catalyst activity by reducing the rhodium inventory and in reducing byproduct formation to improve feedstock efficiency, rather than by making reactors smaller. In selecting the operating temperature, known factors influencing catalyst stability were also considered. The Dow Chemical Company, which acquired Union Carbide in 2001, today operates two plants at the St. Charles site employing the LP OxoSM Process


using LP OxoSM SELECTORSM Technology, using a proprietary bisphosphite-modified rhodium catalyst. Further plants have been licensed to deploy the same catalyst system, one of which operates in Malaysia; the latest SELECTORSM 30 licence was granted earlier this year (2007) for a butanols plant to be built in the Kingdom of Saudi Arabia. The bisphosphite is introduced to the process as the NORMAXTM Catalyst compound, which is available from The Dow Chemical Company. The experience gained from more than eleven years of operation of the first St. Charles plant and process refinements made in recent years have provided the technical platform for the ‘SELECTORSM 30’ Technology that Davy Process Technology offers for licence in collaboration with Dow. The brand name is derived from the ratio of normal to isobutyraldehyde of 30:1 that the process is capable of achieving through the use of NORMAXTM Catalyst. While the SELECTORSM 30 Technology has aroused much interest, Davy Process Technology and Dow are seeing a sustained interest in the TPPmodified catalyst technology for use in propylene applications. This is now marketed under the brand name ‘SELECTORSM 10’ Technology. As the name implies, this refers to the normal to iso ratio of 10:1 with which the TPP process is usually associated. Just this year (2007), Davy Process Technology granted a licence to a Chinese company for a plant for producing approximately 250,000 tonnes per annum in total of 2EH and normal plus iso-butanols employing SELECTORSM 10 Technology. This will be the largest LP OxoSM plant in Asia.

TPP or Bisphosphite? Many factors influence the choice of route for producing oxo derivatives from propylene, and the following highlights some of the parameters on which the choice of ligand can have a significant bearing. The NORMAXTM Catalyst today offers the highest commercially proven isomer selectivity in favour of normal butyraldehyde production. The SELECTORSM 30 Technology will therefore appeal strongly where the production of 2-ethylhexanol (2EH) from the available propylene is to be maximised. Put simply, production of 2EH using SELECTORSM 30

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will typically consume between 6 and 7% less propylene than with SELECTORSM 10, solely as a result of the improved selectivity of conversion to the normal aldehyde. Further improvements in efficiency can result from the reduced formation of byproducts arising from the lower operating temperatures used with the NORMAXTM Catalyst as compared with TPP, and also because of lower propylene purge losses. Plant owners having access to lower-grade, cheaper propylene streams, may also find the NORMAXTM Catalyst system attractive because its high activity will effectively handle dilute feedstreams, such as refinery-grade propylene. Questions concerning the stability of bisphosphite-modified rhodium catalysts in commercial service (and there were many!) have been conclusively answered by excellent experience with those plants now using NORMAXTM Catalyst. This has indicated that exceptional rhodium catalyst life can be expected. In the more than eleven years since the first LP OxoSM plant utilising NORMAXTM Catalyst went into operation at St. Charles, no replacement of the original oxo catalyst charge has been necessary. Furthermore, the rhodium usage has been extremely small. The same picture has emerged for the second St. Charles plant and the licensed plant in Malaysia. The manufacturing cost per kilogramme of NORMAXTM Catalyst is higher than that of TPP. The cost difference is largely compensated for by the large differences in the quantities of these ligands that are needed to operate commercial plants. This is because the benefits of the bisphosphite-modified catalysts are best realised with the ligand present at much lower concentrations in the catalyst solution than is the case with TPP-modified systems. Experience has shown that for commercial propylene systems, the contribution to the cash cost of production by rhodium and ligand for the SELECTORSM 30 Technology is very comparable to its equivalent for SELECTORSM 10. Typically, for the TPP system, the contribution is about U.S.$2 to U.S.$3 per tonne of butyraldehyde, whereas for systems employing NORMAXTM Catalyst, it is about U.S.$5 per tonne. Other factors are influencing licensees of the LP OxoSM Process in their choice of ligand. The highest


possible selectivity to normal butyraldehyde is not always the priority. Some oxo producers desire to produce iso-butyraldehyde to make derivatives such as neopentylglycol, for use in speciality polyesters, or other polyols going into, for instance, volatile free film-formers. The NORMAXTM Catalyst would be inappropriate in such cases. The butyraldehyde section of a 2EH plant licensed in 2003 by Davy Process Technology was designed to use TPP with the capability of being able to vary the normal to iso product ratio from 12:1 to only 6:1 – to provide good flexibility in the amount of iso-butyraldehyde coproduct.

The Influence of Rhodium Metal Prices The price of rhodium metal has varied enormously in the forty years since rhodium first attracted serious attention for hydroformylation catalysis. This variation is plotted in Figure 2 (11, 12). Rhodium is presently more than 25 times more expensive in U.S. dollar terms (11, 12) than it was when the strong economic drivers for rhodium first emerged in the early 1970s. While for plants operating the LP OxoSM Process, the variable cost contribution from rhodium is often barely U.S.$1 per tonne of product, which is extremely modest, the rhodium price can have a large impact on the working capital needed for a new plant investment. In the early 1990s, the monthly rhodium metal price, having never previously been more than U.S.$2000 per troy ounce, quite quickly rose to about U.S.$5000 per troy ounce (12), where it remained for almost a year before easing right back to well below U.S.$1000 per troy ounce. This increase in the rhodium price would have caused concerns among those companies contemplating investing in TPP/rhodium-based technology. Furthermore, it stimulated Union Carbide and Davy Process Technology into planning more proactively for a ‘low rhodium’ version of the LP OxoSM Process. Fortunately, at the time, the lowrhodium solution was already under development in the form of a modified version of the LP OxoSM Process using a more advanced bisphosphite-modified catalyst. To put the effect of the rhodium price into a present-day perspective, even priced at U.S.$5000 per troy ounce (the rhodium price at the time of writing

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Monthly rhodium prices, U.S.$ per troy oz

Fig. 2 Monthly rhodium prices from January 1965 to June 2007 (Source: Johnson Matthey Precious Metals Marketing, U.K.)

7000 6000 5000 4000 3000 2000 1000 0 Jan-65

Jan-75

(early July 2007) is about U.S.$6150 (12)), the cost to the plant operator of the least amount of rhodium possible to start a 150,000 tonnes per annum 2EH plant using SELECTORSM 10 Technology is in the order of U.S.$9 million, which is more than 10% of the inside battery limit (ISBL) investment cost. In practice, the operator would probably wish to keep additional rhodium in reserve. Over a period of years, the rhodium inventory might well build to typically about one and a half times the initial requirement. The SELECTORSM 30 technology has the advantage that, with lower concentrations of rhodium used, the rhodium inventory of a plant can be reduced to less than one third of that needed for SELECTORSM 10. With the rhodium price now having remained relatively high at over U.S.$4500 per troy ounce for over a year (12), some operators of the TPP-based SELECTORSM 10 Technology will be considering a switch from TPP to the NORMAXTM Catalyst. If a much improved selectivity to normal butyraldehyde is a sufficient incentive, they could find that the asset value of surplus rhodium presently locked into a TPP-modified catalyst system (but recoverable from it) could easily pay for a project to convert their plants to SELECTORSM 30. With product values (on a U.S. dollar per tonne basis) at best only quadrupling since the early 1970s, a 25-fold, even 10-fold increase in rhodium prices over the same period might have been expected to


Jan-85 Date

Jan-95

Jan-05

undermine the sustainability of a commercial petrochemical process based on rhodium chemistry. In the case of the LP OxoSM Process, this situation has been avoided through advances in the technology such as those described in this article. The advances have tended to reduce the investment capital required per tonne of product, and have at least partly mitigated the requirement for extra working capital to establish rhodium inventories. The advances have also resulted in significant improvements in operating costs. The net effect of this is that today, oxo alcohols can be manufactured from propylene at a lower cost in real terms than ever before, despite the relatively high cost of raw materials resulting from expensive oil and the current level of the rhodium metal price. This cost-effectiveness has resulted not only from ingenious rhodium chemistry, but also from essential contributions from chemists, process developers and designers, not forgetting the plant operators.

LP OxoSM Today The Dow Chemical Company and Davy Process Technology collaborate through their respective licensing organisations to market and license LP OxoSM Technology for use with propylene in plants employing either SELECTORSM 10 (TPP) or SELECTORSM 30 (NORMAXTM Catalyst) Technology. SELECTORSM 10 is suitable for a normal to iso ratio requirement of between about 6:1

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and 14:1, and SELECTORSM 30 for between 22:1 and 30:1. Based on laboratory trials, a ratio of at least 35:1 is believed to be attainable commercially using the bisphosphite-modified rhodium catalyst employed in SELECTORSM 30 designs. As part of the LP OxoSM licence offering, technology is available for the production from butyraldehyde of 2EH, normal butanol or iso-butanol in any combination. Most of the thirty or so propylene-based LP OxoSM projects so far licensed involve 2EH and/or butanol plants designed by Davy Process Technology.

Other Applications of the LP OxoSM Process The investment by Davy Process Technology and Union Carbide in research and process development has converted the early laboratory promise of rhodium chemistry into commercial realities of wide appeal. The oxo landscape has eventually changed as a result. The ongoing quest for technical excellence driven by the market for butyraldehyde and its derivatives has opened up applications for the LP OxoSM Process for non-propylene uses. LP OxoSM Technology has been used to produce from normal butenes commercial quantities of 2-propylheptanol (2PH), an alternative plasticiser alcohol to 2EH in which there is a growing interest. The commercial 2PH product actually contains 2-propylheptanol as the principal component in an isomeric mixture of C10 alcohols. The phthalate ester plasticiser made from 2PH is often referred to as DPHP, or di(2-propylheptyl) phthalate. DPHP is gradually establishing a place in certain plasticiser markets in Europe and the U.S.A. because of environmental and other factors. It offers advantages as a plasticiser for flexible PVC applications where its low volatility, good long-term stability and excellent outdoor performance can be exploited. The 2PH technology developed by Davy Process Technology and Union Carbide can operate with commercial C4 streams containing 1-butene and 2-butene such as raffinate 2 streams available from methyl tert-butyl ether (MTBE) plants. The high reactivity of a NORMAXTM bisphosphite-modified rhodium catalyst can be exploited so that both the 1-butene and the less reactive 2-butene present in the feedstream contribute as valuable reactive feed


components to ensure the best available overall product yield. Where there is interest from a 2EH producer in producing 2PH in order to exploit a suitable C4 feed source that is likely to be considerably cheaper than propylene, Davy Process Technology is able to design an LP OxoSM plant that is capable of producing either 2EH or 2PH separately by switching between propylene and butene feedstocks. Should the 2EH/2PH producer have a particular requirement to gradually ramp up production of 2PH according to how the market is seen to develop, another possible approach is to produce the two plasticiser alcohols simultaneously by co-feeding propylene and butenes to the oxo system in appropriate proportions, finally separating the 2EH product from the 2PH product. If a co-feed route is adopted, it would be necessary to conduct separate aldol condensation steps on separated C4 and C5 aldehyde streams prior to a combined C8/C10 hydrogenation step, in order to maximise yields of desired products. LP OxoSM Technology has also been developed for, and successfully operates under licence in, a plant for producing C12 to C15 surfactant range alcohols from C11 to C14 olefins derived from Fischer Tropsch synthesis. The plant capacity is 120,000 tonnes per annum. The technology is also being applied in a 125,000 tonnes per annum process plant now in construction for converting 1-heptene (extracted from Fischer-Tropsch products) to 1-octanol. The octanol product is to be used in the production of co-monomer grade 1-octene. Both these applications of the LP OxoSM Process were developed by Davy Process Technology at its Technology Centre at Stockton-on-Tees in the U.K. Figure 3 shows the ‘Mini-Plant’ employed for this purpose.

Conclusion In recent customer surveys made on behalf of Dow and Davy Process Technology, operators of the LP OxoSM Process have commended the ease of operation and the low environmental impact of the plants, their high reliability and their low maintenance requirements. A successful resolution of various issues in

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Fig. 3 Oxo ‘Mini-Plant’ at Davy Process Technology’s Technology Centre, Stockton-on-Tees, U.K.

rhodium catalyst management has been essential to the commercialisation of the process. This success should provide convincing encouragement to researchers, who are keen to exploit pgms as catalyst materials, but who are apprehensive as to the implications of their very high intrinsic value. It should also encourage developers and designers who

are entrusted with turning pgm chemistry into commercial processes, but who may be daunted by problems such as pgm containment and catalyst life. The LP OxoSM Process is recognised as one of the best known applications of industrial-scale chemistry using a pgm. The promise of rhodium chemistry first observed forty years ago has transformed the manufacturing base of a petrochemical sector. Davy Process Technology and The Dow Chemical Company are continuing in their efforts to build on and extend the significant contribution made towards this transformation by the LP OxoSM Process. Their market focus and continuing efforts in research and process development programmes driven by a sustained market interest will likely mean that the LP OxoSM Process will continue to play an important role in industrial hydroformylation applications for many years to come. LP OxoSM and SELECTORSM are service marks of The Dow Chemical Company. NORMAXTM is a trademark of The Dow Chemical Company.

References 1 R. Tudor and M. Ashley, Platinum Metals Rev., 2007, 51, (3), 116 2 Davy Process Technology Ltd.: http://www.davyprotech.com/ 3 The Dow Chemical Company: http://www.dow.com/ 4 Union Carbide Corporation: http://www.unioncarbide.com/ 5 David R. Bryant and Ernst Billig, ‘Phosphites in Hydroformylation’, in: Royal Society of Chemistry Dalton Division, Fourth International Conference on The Chemistry of the Platinum Group Metals, University of Cambridge, Cambridge, U.K., 9th–13th July, 1990 6 C. F. J. Barnard, Platinum Metals Rev., 1990, 34, (4), 207

7 David R. Bryant, ‘Four Steps in Hydroformylation Technology’, in: American Chemical Society 203rd National Meeting, San Francisco, California, U.S.A., 5th–10th April, 1992 8 E. Billig, A. G. Abatjoglou and D. R. Bryant, Union Carbide Corporation, ‘Transition Metal Complex Catalyzed Processes’, U.S. Patent 4,668,651; 1987 9 E. Billig, A. G. Abatjoglou and D. R. Bryant, Union Carbide Corporation, ‘Bis-phosphite Compounds’, U.S. Patent 4,748,261; 1988 10 E. Billig, A. G. Abatjoglou and D. R. Bryant, Union Carbide Corporation, ‘Bis-phosphite Compounds’, U.S. Patent 4,885,401; 1989 11 Johnson Matthey Precious Metals Marketing, U.K. 12 Platinum Today, PGM Prices, Current and Historical: http://www.platinum.matthey.com/prices/current_ historical.html

The Authors Richard Tudor is a chartered chemical engineer. He has played a leading part in Davy Process Technology’s oxo licensing activities for over thirty years, firstly as Process Manager, and then as Business Manager after a period as Licensing Manager. As a Vice President of sales and marketing, he now has overall responsibility for the oxo business.


Mike Ashley spent many years with John Brown, involved with process technology and business development, before joining Davy Process Technology. He is now concerned with business analysis, technology acquisition, marketing, website development and all aspects of public relations.

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DOI: 10.1595/147106707X233928

Novel Chiral Chemistries Japan 2007 Reviewed by David J. Ager DSM, PMB 150, 9650 Strickland Road, Suite 103, Raleigh, NC 27615, U.S.A.; E-mail: [email protected]

The second Novel Chiral Chemistries Japan (NCCJ) Conference and Exhibition was held in Tokyo from 16th to 17th April, 2007. The first meeting in the series had been held in 2006 and a similar format was followed. There were three keynote addresses with supporting lectures. Professor Takao Ikariya (Tokyo Institute of Technology) did an excellent job as the conference organiser. During the coffee and lunch breaks there was a small exhibition by companies associated with chiral chemistry. The exhibitors ranged from companies that provide biocatalysts, metal catalysts and ligands through to service providers associated with the implementation of methodologies. Some scientific instrumentation was also on display. There were about 100 delegates, most coming from the Japanese fine chemicals industry.

Keynote Presentations There were three keynote addresses. The first was by Professor Henri Kagan (University ParisSud, France) who described some of the general problems associated with finding a catalyst for a specific purpose when non-linear effects are observed. This was highlighted by examples of asymmetric depletion, when a low degree of asymmetric induction can occur unless the catalyst has an extremely high enantiopurity. The second keynote address was presented by Professor Gregory Fu (Massachusetts Institute of Technology, U.S.A.). This lecture covered the development of chiral nucleophilic catalysts based on 4-aminopyridines bound to ferrocene derivatives. These catalysts have proved useful for the asymmetric conversion of ketenes to α-substituted esters. In the presence of copper, the ferrocene derivatives can be used to prepare α-alkoxy esters. This chemistry has led to the development of chiral azaferrocenes for the asymmetric formation of cyclopropanes from diazocompounds.


The third and final keynote address was by Professor Tsuneo Imamoto (Chiba University, Japan) who described how his work had progressed from BisP*, 1, and MiniPhos, 2, to other ligands based on the concept of P-chirality, as originally implemented by Knowles with DIPAMP (1). R

R P

P

P R

1

P R

BisP** BisP

2

MiniPhos

R = alkyl substituent

The synthesis of both ligand series involves organometallic chemistry, with the phosphorus stabilised as a borane adduct for asymmetric deprotonations with sec-butyllithium in the presence of sparteine. The rhodium complexes of these ligands provide high enantioselectivity in the reduction of dehydroamino acid derivatives, enol esters and enamides. Hydrosilylation of ketones provides access to chiral secondary alcohols. The iridium complexes of these ligands can be used to reduce imines to amines, again with high stereoselectivity. This work is now being extended to AlkynylP*, where the methyl group of BisP* has been replaced by alkynyl groups. These ligands have shown high selectivity for the addition of arylboronic acids to enones. This latter reaction can also be performed with QuinoxP*, 3, which also provides high asymmetric induction in the rhodium-catalysed reduction of enamides and palladium-catalysed addition of dialkylzinc to 7-oxabicyclohepta[2.2.1]dienes. R N

P

N

P R

3

QuinoxP*

R = alkyl substituent

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Asymmetric Catalysis In addition to these keynote addresses, there were fifteen other presentations. The topics ranged from the use of biocatalysts and chiral auxiliaries through to the design of ligands and applications of both approaches in pharmaceutical case studies. Only the talks relating to the use of platinum group metals (pgms) have been summarised here, in line with the emphasis of this publication. Rocco Paciello (BASF, Germany) described how the phosphanylpyridones designed by Professor Bernhard Breit from the University of Freiburg, Germany, can be used in hydroformylation reactions of terminal alkenes in the presence of rhodium, to provide high selectivity for the formation of aldehydes. Asymmetric reactions were illustrated by hydrogenations where phosphonites from the Breit collaboration are available. Catalyst screening was the topic of a number of the presentations, and the BASF approach was illustrated by a synthesis of (R)-2-methylpentanol where the successful ligand for the rhodium-catalysed reduction of the allyl alcohol precursor was SolPhos, 4. For the reduction of itaconic esters, rhodium with RoPhos, 5, was found to be the successful combination. OH

N

OH P

O

PPh2

O

PPh2 P OH

N

Institution and the Universities of Liverpool and Southampton, U.K., on computational investigation into ketone reduction with the rutheniumBINAP-DPEN system. There seem to be significant differences in performance between the XylBINAP and TolBINAP systems. This could be due to the way in which the substrate docks with the metal catalyst (2). Hideo Shimizu (Takasago International Corp., Japan) described work on the direct reduction of enamines to β-amino esters with DM-SegPhos, 6. The second part of the talk was on new work related to the reduction of aryl ketones by the use of copper catalysts with BDPP, 7, (also known as SkewPhos) as the chiral ligand.

O O

P(3,5-xyl)2

O

P(3,5-xyl)2

PPh2 PPh2

O

6

7 BDPP (SkewPhos)

DM-SegPhos DM-SegPhos

Professor Hisao Nishiyama (Nagoya University, Japan) described his work with Rh(Phebox), 8, for the conjugate reductions of α,β-unsaturated esters, enals and enones. As an enolate is formed in the reaction, the intermediate can be reacted with an electrophile to perform aldol and other reactions. This approach gives a rapid and powerful approach to chiral 3-hydroxy2-alkyl esters.

OH

4

SolPhos SolPhos

5

RoPhos

For the reduction of ketones, transfer hydrogenation is the preferred method of operation and this is being scaled up using a continuous process. In addition, the presence of a small amount of carbon monoxide has been found to be advantageous. Antonio Zanotti-Gerosa (Johnson Matthey, U.K.) described work that has been done by Johnson Matthey, in collaboration with the Royal


O

O

i-Pr

N AcO

OAc N Rh OH2

Pr-i

(H O) 8 Rh(ip-Phebox)(OAc) Rh(PheBox)(OAc)2(H2 2O)2

Hans-Jürgen Federsel (AstraZeneca, Sweden) gave a number of examples of different approaches for the preparation of chiral pharmaceutical compounds. For the synthesis of a complex 2-aminotetralin, the nitrogen at the

173

to chiral amines include the use of catASium® D, 10, to prepare α-amino acids from α-keto acids and a transfer hydrogen method with ruthenium TolBINAP for ketones.

stereogenic centre was introduced by a reductive amination with phenylethylamine. The BuchwaldHartwig approach with palladium acetate in the presence of BINAP afforded the piperazine coupled product (Scheme I). Professor Jaiwook Park (Pohang University of Science and Technology, South Korea) described his work on the dynamic kinetic resolution of amines through the use of enzymes to stereospecifically prepare an amide from racemic amine. A metal catalyst provides the ability for an in situ recycling of the amine enantiomer that is not a substrate for the enzyme. The metal catalyst is based on palladium nanoparticles entrapped in aluminium hydroxide, prepared by heating aluminium tri-sec-butoxide and tetrakis(triphenylphosphine)palladium in butanol in air. The theme of a dynamic kinetic resolution was continued by Renat Kadyrov (Degussa Homogeneous Catalysts, Germany), who described how the use of Rh(Norphos), 9, could be employed for the reduction of racemic N,O-acetals, aminols, to prepare chiral amines, as 1,2-amino alcohols. Other reductive approaches

PPh2

Ph2P

PPh2

Ph2P

N

Bn

10 catASium® D catASium D (Bn = benzyl)

NorPhos 9 NorPhos

Makoto Itagaki (Sumitomo Chemical Co., Ltd., Japan) described the development of catalysts for the asymmetric synthesis of cyclopropanes. In addition to control of enantioselectivity, the cis:trans ratio has to be controlled. The products are used in the agricultural industry and may be applied as a mixture, but there is still a need to produce the active isomer in the most costefficient manner available. The development of catalysts for the addition of the diazoesters to alkene has led to the copper-pybox analogue 11. David Ager (DSM, U.S.A.) described the methods employed to find the best catalyst for an

H 2N

TsOH

O

N

Br

Br

HN

1. NaBH4, MeOH, IPA 2. HCl, EtOAc Br

N

Pd(OAc)2, BINAP, NaOBu-t, toluene NaOtBu, toluene

N H 55% 92% de

N H

N

H22,, PdÐC, Pd/C, H 1. H H22O, O, AcOH AcOH 2. PhCO2H, toluene

HO2CPh NH2 •¥H N N

N 95%

88%

Scheme I Synthesis of a complex 2-aminotetralin (de = diastereomeric excess)


174

O

acid provides the desired isomer as isomerisation of the substrate occurs under the conditions employed for the reduction.

O N

Cu

PF6

N

S PPh2 PPh2

11

Cu-pybox analogue

S

asymmetric transformation. The ligand system is a monodentate phosphoramidite and those based on BINOL are known as the MonoPhosTM, 12, family. These ligands can provide excellent asymmetric induction for the reduction in the presence of rhodium of a wide range of carbon–carbon double bonds (3). The ligands are now proving useful in the rhodium-catalysed additions of arylboronic acids to aldehydes and imines. R2

R1 O O

R2

12

R3 P

N R4

R1 TM family MonoPhos MonoPhos family

Yongkui Sun (Merck & Co., U.S.A.) described how screening is a powerful tool to find asymmetric catalysts in the pharmaceutical industry. Three case studies were presented. The first involved a dynamic kinetic resolution approach for the reduction of a ketone to alcohol with control of the α-stereocentre to produce the desired isomer. The method used a Noyori approach. The synthesis also involved the conversion of an aryl bromide to nitrile with Pd(o-Tol)4 and zinc cyanide. In the second example, the target molecule was the same, but Rh(TMBTP), 13, was used to reduce an enamide. For this approach, the enamide was prepared by a palladium-catalysed coupling of a vinyl tosylate with an amide. The third example was for the synthesis of sitagliptin, where a Ru(BINAP) reduction of an unsaturated


13 TMBTP TMBTP

Concluding Remarks As with the first meeting, NCCJ 2007 was held in the same week as CPhI Japan (4). The meeting allows interactions between Japanese companies and academics with their counterparts from Europe and the U.S. In addition to new methodologies, application of methods and the problems associated with implementation in industrial settings provide a background emphasising the need to develop both more efficient catalysts and the means to identify them. The wide variety of topics and applications discussed demonstrates that use of the pgms continues to provide new and useful methodologies to prepare molecules on an industrial scale. I hope this excellent series continues to grow and prosper.

References 1 2 3 4

W. S. Knowles and M. J. Sabacky, Chem. Commun. (London), 1968, 1445 S. A. French, Platinum Metals Rev., 2007, 51, (2), 54 D. J. Ager, A. H. M. de Vries and J. G. de Vries, Platinum Metals Rev., 2006, 50, (2), 54 CPhI Japan: http://www.cphijapan.com/eng/

The Reviewer David Ager has a Ph.D. (University of Cambridge), and was a post-doctoral worker at the University of Southampton. He worked at Liverpool and Toledo (U.S.A.) universities; NutraSweet Company’s research and development group (as a Monsanto Fellow), NSC Technologies, and Great Lakes Fine Chemicals (as a Fellow) responsible for developing new synthetic methodology. David was then a consultant on chiral and process chemistry. In 2002 he joined DSM as the Competence Manager for homogeneous catalysis. In January 2006 he became a Principal Scientist.

175

DOI: 10.1595/147106707X231560

“Recent Developments in the Organometallic Chemistry of N-Heterocyclic Carbenes” GUEST EDITOR: ROBERT H. CRABTREE (Yale University, U.S.A.), Coordination Chemistry Reviews, 2007, Special Issue, Volume 251, Issues 5–6, pp. 595–896

Organometallic catalysis has been based for years on phosphine and cyclopentadienyl ligands. These stood alone as the leading ligand classes because they were sterically and electronically tunable to achieve desired levels of catalyst selectivity and activity. In the case of the phosphine series, such tuning was particularly easy using the Tolman ‘map’ that predicted the steric and electronic effects of almost any phosphine or related phosphorus donor ligand (1, 2). N-Heterocyclic carbenes (NHCs), 1, are ligands formed by the deprotonation of an N,N′-disubstituted imidazolium (or other azolium) salt. Binding of a transition metal to the C2 carbon of the NHC leads to the formation of a very strong metal– carbon bond, the strength deriving from the thermodynamic instability of the free NHC. Unlike metal–carbon bonds in general, those to NHCs do not undergo fast insertion or reductive elimination reactions and so NHCs are relatively reliable spectator ligands. The role of a spectator ligand is to act as a placeholder by promoting a desired reaction at the metal, while avoiding dissociation or entering directly into the reaction. NHCs are significant in being the first new series of spectator ligands in several decades to rise to prominence, having both steric and electronic tunability and the capability to promote catalysis of many useful catalytic reactions.

NR

RN ••

1 N-Heterocyclic NHCcarbene (NHC)

Early work in the 1960s and 1970s laid out the basis of the field but the full potential of these ligands was not fully realised at that time. Only with


work from the 1990s and specially since 2000 have these ligands achieved major prominence. Perhaps the most dramatic example of their utility was the discovery by Grubbs and coworkers (3) that NHC ligands could greatly improve the performance of the Grubbs ruthenium metathesis catalyst. A recent special issue of Coordination Chemistry Reviews, with guest editor Robert H. Crabtree, has now been devoted to the NHC ligands (4). Among several notable reviews, Ivan Lin and Chandra Vasam address Lin’s metallation procedure for the synthesis of NHC complexes. The procedure is important in that it avoids strong base and instead uses Ag2O to metallate the usual N,N′-disubstituted imidazolium NHC precursor salt. This is now one of the most popular methods of introducing NHCs into metal complexes, because the silver NHC complexes initially formed readily transmetallate to other metals, such as palladium or rhodium. Polly Arnold and Stephen Pearson describe the chemistry of abnormal NHCs, in which a metal is bound not at the usual C2 carbon but at C4(5). These are much stronger electron donors, but somewhat more easily cleaved from the metal compared with their normal NHC analogues. Andreas Danopoulos and David Pugh treat ‘pincer’ versions of NHCs, a ligand type that has been very fruitful in terms of catalytic complexes, both in the NHC and in the phosphine series.

N-Heterocyclic Carbenes in Catalysis and Biomedicine Lutz Gade and Stéphane Bellemin-Laponnaz’s review deals with oxazoline-modified NHCs in relation to asymmetric catalysis. Steven Diver discusses recent advances in enyne metathesis with NHC ruthenium complexes. Asymmetric catalysis

176

continues to be of intense interest and many asymmetric NHCs have been developed. For example, Richard Douthwaite discusses palladium-mediated asymmetric alkylation using chiral NHCs derived from chiral amines. Frédéric Lamaty et al. review the NHC-modified Grubbs catalysts. Valerian Dragutan and coworkers review other aspects of ruthenium NHC catalysis. Miguel Esteruelas et al. look at a related element, osmium, and its carbene chemistry. Eduardo Peris and coworkers review some ligands with NHCs in bidentate and tripod configurations, together with their catalytic properties. Marcus Weck and William Sommer cover supported catalysis involving NHC ligands with ruthenium and palladium. In connection with the problem of predicting the stereoelectronic properties of NHCs, Steve Nolan and Silvia Díez-González discuss their development of a set of reliable stereoelectronic parameters for NHC ligands with a view to understanding how stereoelectronic effects control metal-catalysed reactions. Wiley Youngs and coworkers go far beyond catalysis into the biomedical area. They show that silver NHC complexes can have useful anti-

microbial activity. Encapsulation in a polymer mat allows sustained delivery of silver ions, useful in wound care. Numerous resistant respiratory pathogens in cystic fibrosis are sensitive to a caffeine-derived silver-NHC complex.

Concluding Remarks This field holds much promise for future development because of the very large range of possibilities opened up by the availability of a vast range of azole structures of various sorts. We can expect other azoles, such as triazole and thiazole derivatives, for example, as well as a large array of different chelate arrangements and mixed ligand systems. For catalytic applications, NHCs have been chiefly incorporated into platinum group metals, but they prove to have a much wider affinity for d-block, f-block and main group elements than do phosphines or cyclopentadienyls, so their ultimate potential is vast.

References 1 2 3 4

C. A. Tolman, J. Am. Chem. Soc., 1970, 92, (10), 2953 C. A. Tolman, Chem. Rev., 1977, 77, (3), 313 T. M. Trnka and R. H. Grubbs, Acc. Chem. Res., 2001, 34, (1), 18 Coord. Chem. Rev., 2007, 251, (5–6), 595–896

The Guest Editor of the Review Bob Crabtree, educated at New College, Oxford, U.K. with Malcolm Green, did his Ph.D. research with Joseph Chatt at Sussex and then spent four years in Paris with Hugh Felkin at the Centre National de la Recherche Scientifique (CNRS). He has been at Yale University since 1977, where he is now Professor. He has received several awards: A. P. Sloan Fellow, Dreyfus Teacher-Scholar, American Chemical Society (ACS) and Royal Society of Chemistry organometallic chemistry prizes, H. C. Brown Lecturer, Mack Award, Baylor Medal and Sabatier Lecturer. He has chaired the Inorganic Division at the ACS. He is the author of a textbook in the organometallic field, and editor-in-chief of the “Encyclopedia of Inorganic Chemistry” and “Comprehensive Organometallic Chemistry”. Early research on catalytic alkane C–H activation and functionalisation chemistry was followed by work on C–F bond activation, H2 complexes, M–H…H–O hydrogen bonding, and molecular recognition in C–H activation. His homogeneous hydrogenation catalyst is in wide use.


177

DOI: 10.1595/147106707X237708

Annealing Characteristics and Strain Resistance of 99.93 wt.% Platinum IMPLICATIONS FOR THE MANUFACTURE OF PLATINUM ARTEFACTS By Yu. N. Loginov* Ural State Technical University, Metallurgical Department, 19 Mira Street, 620002 Ekaterinburg, Russia; *E-mail: [email protected]

and A. V. Yermakov**, L. G. Grohovskaya and G. I. Studenok The Ekaterinburg Non-Ferrous Metals Processing Plant JSC, 8 Lenin Avenue, 620014 Ekaterinburg, Russia; **E-mail: [email protected]

In industrial applications, platinum is often used in the form of the nominally pure metal, since impurities and alloying elements may adversely affect both its working characteristics and its stability against corrosion, at both ambient and high temperatures. Low strength, typical of a metal of this purity, is accepted in industrial products despite being a significant disadvantage. To optimise the technical parameters for the thermal and mechanical processing of platinum, knowledge is required of its rheological characteristics, including deformation resistance.

There has been much recent interest in the technical literature in the rheological features of platinum alloys for jewellery applications (1, 2). By contrast, in industrial applications, platinum is often used in the form of the nominally pure metal, since impurities and alloying elements can adversely affect its working characteristics (3, 4). 99.93 wt.% pure platinum is used in Russia, for instance, to produce heat- and chemical-resistant crucibles. To comply with the Russian State Standard GOST 13498-79 (5), platinum must be at least 99.93 wt.% pure (i.e. the overall total impurity content is not more than 0.07 wt.%). Palladium, rhodium, iridium and ruthenium impurities must not exceed 0.04 wt.% in total, and the upper limits (in wt.%) for other impurities are as follows: silicon 0.005, iron 0.01, gold 0.008 and lead 0.006. It should be noted that unlike alloys, the mechanical characteristics of pure metals depend strongly on their impurity content, which must be determined experimentally. 99.917 wt.% pure platinum test samples were prepared for the present work. Impurity levels (in wt.%) were analysed as follows: Pd 0.06, Rh 0.01, Ir 0.007, Si 0.001, Fe 0.003, Au 0.001 and Pb 0.001. The chemical composition of the platinum test samples was therefore close to that required by GOST 13498-79.


The test blanks for the current work were obtained by means of cast moulding a platinum bar 50 mm thick and hot forging at 900 to 1530ºC, with subsequent cold rolling of the sheet material. The thicknesses of sheets obtained by rolling of the 25 mm forged blanks were 1.25, 0.83, 0.71, 0.63 and 0.56 mm. The forged blanks underwent annealing in a batch furnace at a temperature of 1000ºC for 40 minutes, so as to achieve recrystallisation. This temperature was initially assumed to be high enough to ensure complete recrystallisation (2). Using such a high annealing temperature industrially is controversial, since it can adversely affect the structure of the metal and some of its working characteristics. In determining the force/energy parameters for processes involving pressure working, the strain resistance, σs, is understood to be a function of the strain state of the sample, in terms of compression and degree of strain (6). The deformation resistance is considered in terms of the uniaxial compression or tension of the sample under conditions of plastic deformation. It was assumed that during cold deformation, the deformation resistance depends only on the geometric parameters of the change in shape. In order to plot hardening curves as a function of deformation, starting at zero, the original material must be fully recrystallised. To establish the

178

transition temperature for recrystallisation, experiments were set up to determine the yield limit as a function of the annealing temperature. An initial shear strain Λ was determined by varying the compression ε% of the blanks during cold sheet rolling (i.e. in the flat deformed condition), and calculated by Equation (i): Λ = 2ln(h0/h1)

(i)

where h0 and h1 are the sample thicknesses before and after rolling, respectively. We also defined:

ε% = 100Δh/h0

(ii)

where Δh = h0 – h1. Using the generalised deformation characteristic Λ allows for summation as the deformation accumulates. This approach is also compatible with the majority of computer programs for calculating stress-strain characteristics. The prepared platinum strips were rolled to a final thickness of 0.5 mm on a mill with 300 mm diameter rollers, imparting them with varying degrees of cold working. Flat ten-fold samples were then cut from the sheets, with their long axes oriented along the rolling axis. The samples were then annealed at temperatures from 200 to 1100ºC.

Tension tests were conducted on an “Instron 1195” machine, using a traverse speed of 1 mm min–1, and the Vickers hardness HV5 was measured. Hardness is plotted against annealing temperature in Figure 1, the legend for which is given in Table I.

Results of Hardness Testing The experimental results showed that the Vickers hardness of platinum can vary very considerably within the wide range 500–1500 MPa, depending upon the degree of strain. It should be noted that standard references (e.g. (7)) give the Vickers hardness of platinum of technical purity, in the annealed state, in the range 350–420 MPa; calculation from the HV value in Reference (8) gives Table I

Legend for Figure 1 Symbol

Λ (averaged data)

h0, mm

h1, mm

0.15 0.40 0.68 0.97 1.91 7.78

0.560 0.630 0.710 0.830 1.250 25.000

0.520 0.515 0.505 0.510 0.480 0.505

c × * z

Fig. 1 Experimental schematic and results for measurement of dependence of Vickers hardness, HV5, for 99.93 wt.% platinum on annealing temperature, t0, and initial degree of shear strain, Λ (averaged data). See Table I for legend

0


200

400

600

800

1000

1200

179

392 MPa. This spread of values is explained by the varying chemical composition of the platinum samples tested; in the present work, the platinum contained 0.01 wt.% rhodium as the principal strengthening element. Figure 1 shows that full annealing is reached on heating to 400ºC if the metal is cold-worked to the high degree of shear strain of 7.78 (compression ε% = 97.96%). With decreasing initial deformation, the annealing point shifts towards higher temperatures. Thus, with a degree of initial shear deformation greater than 0.4 (compression 18%), the annealed state is reached at temperatures above 700–800ºC. At lower degrees of compression, the metal can be softened only by heating to above 1000ºC. Figure 2 shows the dependence of the annealing temperature t0 of platinum on initial shear strain. Regression analysis gives Equation (iii) for this dependence, with a correlation coefficient of 0.982:

t0 = 695 – 141 ln(Λ)

This stored energy derives from heating during the annealing process. As a result, the annealing temperature may be lower for hardened than for unhardened metal.

Deformation Resistance The sheet material used for the present experiments was prepared by repeated rolling of flat platinum samples. The results of tension tests provided values of yield strength corresponding to uniaxial tension, and hence the deformation resistance σs. There are two principal methods for determining deformation resistance. In the first, flat specimens are rolled on a mill to a range of thicknesses. The specimens are then subjected to uniaxial tension tests, so as to determine the conventional yield strength. This is an empirical parameter, defined in terms of the stress which will produce a given degree of conventional strain. σ0.2 is defined as the stress to produce 0.2% conventional strain. It is usually assumed that σs = σ0.2, since both parameters refer to the start of plastic deformation. The advantage of this method is that no neck is formed, and high degrees of plastic deformation are therefore attainable. The second method is uniaxial tension testing, during which true (not conventional) stress and deformation are measured. Plots of σs vs. either ε% or Λ are obtained. A disadvantage of this method is that a neck is formed, and large deformations can-

(iii)

Minimising the annealing temperature on the basis of the degree of deformation in the metal is technologically significant, since at higher annealing temperatures, collective recrystallisation occurs and grain size increases, and the plastic characteristics are adversely affected. The decrease in recrystallisation temperature with increasing shear strain may be explained in terms of an accumulation of internal energy in the crystal lattice during cold working.

Fig. 2 Influence of initial shear strain, Λ, on annealing temperature, t0, of 99.93 wt.% platinum

Λ

0

1

2


3

4

5

6

7

8

180

not be achieved. In this work, σ0.2 is taken as a measure of the stress at which plastic deformation begins under uniaxial tension. σs is adopted for stress-strain calculations in which the stress condition is not one of uniaxial tension. Experimental measurements have provided results for σ0.2 as a function of the degree of preliminary hardening. Different researchers employ a variety of factors in evaluating metal hardening. Here, we consider deformation in terms of: the shear deformation, Λ, given by Equation (i): Λ = 2ln(h0/h1)

(i)

and the relative compression ε%, given by Equation (ii):

ε% = 100Δh/h0

(ii)

In order to plot hardening curves for metals in the cold state, it is important, where possible, to measure accurately the nominal yield strength of the metal in the unhardened state. Experiments in processing semi-finished platinum products showed that the conventional yield strength of the material is rather variable, by contrast with its tensile strength. Plots of the dependence of σ0.2 on the initial shear deformation and the annealing point (Figure 3) showed that

GOST 13498-79 grade platinum may have a yield strength anywhere in the range 50 to 230 MPa, depending on its thermomechanical processing history. The yield strength decreases with increasing annealing temperature. It was found that, at lower annealing points (600 to 700ºC), the dependence of σ0.2 on Λ shows a maximum in the range Λ = 0.8 to 1.5, corresponding to ε% = 30 to 50%. At higher temperatures, σ0.2 decreases monotonically with increasing Λ. At annealing points in excess of 1000ºC, the prior cold working of the metal ceases to have an effect. Under softening conditions, σ0.2 takes a characteristic value of 60 MPa, and this was treated as a constant in the regression equations. The experimental results may be explained as follows. At low annealing temperatures, σ0.2 increases with increasing Λ, because the metal has been subjected to hardening by cold rolling. Under these conditions, annealing has little softening influence. However, if Λ rises to between 0.8 and 1.5, annealing has sufficient influence to soften the metal. σ0.2 therefore decreases again, and the curve shows a maximum. If the annealing temperature is over 800ºC, the curves show no maxima, because the influence of annealing is sufficient for full softening, without taking into account the energy of plastic

Fig. 3 Experimental schematic and results for measurement of dependence of conventional yield strength, σ0.2, for 99.93 wt.% platinum, on initial degree of shear strain, Λ, and annealing temperature, t0: 600ºC; z 700ºC; * 800ºC; × 900ºC; 1000ºC; c 1100ºC


181

deformation. The practical significance of this observation lies in the possibility of choosing annealing regimes to obtain the desired metal characteristics. For example, in some industrial applications, pure platinum is used as a fabrication material, in spite of the low strength of products made from it. Improved products with greater strength, desirable for vessels and crucibles, may be achieved through plastic deformation and partial annealing.

Figure 5, which indicates that the deformation resistance of the metal may vary between 60 and 460 MPa. Depending on the case selected, linear regression analysis gave Equations (iv)–(vi) for the hardening curve:

Effect of Annealing Temperature on Grain Size

The amount of strain, ε, is given by ε = ln(h0/h1). The correlation coefficient of regression for Equations (iv) and (v) is 0.9873, and for Equation (vi), 0.9726. These values indicate that the approximations are satisfactory. Determining the exponent in Equation (iv) enables the degree of deformation in platinum under draw-forming to be predicted. In accordance with plasticity theory, the sheet retains its shape without necking, if the exponents in Equations (iv) or (v) are high enough.

Higher annealing temperatures increase grain size. This effect is particularly evident at temperatures over 900ºC, where it is attributable to collective recrystallisation (Figure 4). A fine crystal structure is preferred for the deep forming of vessels and crucibles. The dependence of conventional yield strength on shear deformation for Pt 99.93 is shown in

(a)

(b)

Fig. 4 Structure of 99.93 wt.% platinum (× 100) after cold rolling at Λ = 1.91 (h0 = 1.250 mm, h1 = 0.480 mm) and annealing for 40 minutes at: (a) 800ºC; and (b) 1000ºC

σs = 60 + 214Λ0.334

(iv)

σs = 60 + 269ε0.334

(v)

σs = 60 + 39.8ε%0.481

(vi)

Stress-Strain Analysis Stress-strain conditions during the deformation of platinum crucibles have been calculated by finiteelement methods (9). Figure 6 shows the results for deep drawing of a product of thickness S, using a die of radius rm. The shear deformation Λ shows a non-uniform distribution, with its maximum at the punch radius. There are two shear deformation maxima along the radius of the sample, which correspond to the two hardening maxima. These investigations of annealing regimes and hardening conditions have practical implications for the production of platinum vessels at the Fig. 5 Dependence of deformation resistance, σs, on shear strain, Λ, for 99.93% platinum


182

Fig. 6 Detail of stress-strain calculation for deep drawing of platinum at rm/S = 8

Ekaterinburg Non-Ferrous Metals Processing Plant, Russia. The plant produces chemically stable platinum crucibles in a range of shapes (see Table II). A selection is shown in Figure 7.

Conclusions The annealing temperature range for 99.93 wt.% platinum is 400–1000ºC, and depends on the degree of cold working. Annealing is possible at

400ºC if the shear strain Λ is at least 7.78, or the relative compression ε% is at least 97.96%. Annealing at temperatures higher than 900ºC increases grain size; this is attributable to collective recrystallisation. Depending on the strain condition, the preferred annealing temperature range is therefore 400 to 800ºC. The conventional yield strength σ0.2 depends non-linearly on the degree of shear deformation. This has been analysed in terms of hardening by a regression analysis. At low annealing temperatures, σ0.2 increases with increasing Λ, because the metal has been subjected to hardening by a cold rolling process. However, if Λ rises to between 0.8 and 1.5, annealing is sufficiently powerful to soften the metal. σ0.2 therefore decreases, and the curve shows a maximum. The strain resistance of 99.93 wt.% platinum ranges from 60 to 460 MPa as Λ increases from 0 to 7.78. The data obtained in the present work allow stress-strain relations to be calculated as a function of deformation for semi-finished platinum artefacts.

Table II

Dimensions of Some of the Shapes of Platinum Crucible Produced by Ekaterinburg Non-Ferrous Metals Processing Plant, Russia Diameter, mm 8 28 38 42 135

Height, mm 8.5 22 128 30 150

References 1 2 3 4 5

J. C. Wright, Platinum Metals Rev., 2002, 46, (2), 66 T. Biggs, S. S. Taylor and E. van der Lingen, Platinum Metals Rev., 2005, 49, (1), 2 K. Toyoda, T. Miyamoto, T. Tanihira and H. Sato, Pilot Pen Co Ltd, ‘High Purity Platinum and Its Production’, Japanese Patent 7/150,271; 1995 K. Toyoda and T. Tanihira, Pilot Pen Co Ltd, ‘High Purity Platinum Alloy’, Japanese Patent 8/311,583; 1996 Russian State Standard GOST 13498-79, ‘Platinum and Platinum Alloys.’ ‘Trade Marks’, Moscow, 1979

Fig. 7 Chemically stable platinum crucibles. (The red coloration is a reflection of the background.)


183

6

7

E. P. Unskov, W. Johnson, V. L. Kolmogorov, E. A. Popov, Yu. S. Safarov, R. D. Venter, H. Kudo, K. Osakada, H. L. D. Pugh and R. S. Sowerby, “Theory of Plastic Deformations of Metals”, Mashinostroenie, Moscow, 1983 (in Russian) “Precious Metals Handbook”, ed. E. M. Savitsky, Metallurgiya, Moscow, 1984, (in Russian)

8

9

Properties of Platinum Group Metals: Platinum Today, Johnson Matthey: http://www.platinum.matthey.com/applications/ properties.html Yu. N. Loginov, B. I. Camenetzky and G. I. Studenok, Izvestiya Vysshikh Uchebnykh Zavedenii, Chernaya Metallurgiya, 2006, (3), 26

The Authors Yuri N. Loginov, Dr.Sc. (Techn.) is the Professor in the Metallurgical Department of the Ural State Technical University, where he directs work on the plastic deformation of nonferrous metals. He is the author of four monographs, 40 university-level textbooks, 300 scientific publications and 120 patents.

Alexander V. Yermakov, Cand.Sc. (Phys. & Math.), is a Senior Researcher and the Deputy Director of the Ekaterinburg Non-Ferrous Metals Processing Plant. He is the author of monographs and over 150 scientific publications and patents. His interests lie in the study of the properties of noble metals and their alloys, and creation of industrial technology for their fabrication.

Lilia G. Grohovskaya is a supervisor in the research laboratory section of the Ekaterinburg Non-Ferrous Metals Processing Plant. She has wide experience in noble metals research.

Gennadi I. Studenok, an engineer in the scientific laboratory of the Ekaterinburg NonFerrous Metals Processing Plant, is a Ph.D. student in the Metallurgical Department of the Ural State Technical University, researching the mechanics of deformation processes in noble metals.


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DOI: 10.1595/147106707X234800

40th Conference ‘Deutscher Katalytiker’ PLATINUM GROUP METALS AT THE GERMAN CATALYSIS CONFERENCE Reviewed by Thomas Ilkenhans Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.; E-mail: [email protected]

The conference was held in Weimar, Germany, from 14th to 16th March 2007 (1). It was the 40th anniversary of this annual meeting, which was founded in 1967 in eastern Germany. The conference attracted more than 450 visitors from industry and academia, mainly from Germany. Forty lectures in two parallel sessions were presented, and there were more than 200 poster contributions. Of the six plenary lectures, four were given by international speakers. This selective review covers aspects of the presented work featuring the platinum group metals (pgms).

Lectures J.-M. Basset (École Supérieure Chimie Physique Électronique de Lyon, France) described in his plenary lecture: ‘Catalysis: From Molecules to Materials’, the progress of molecular and supramolecular chemistry for the rational design of catalysts. With numerous examples, such as for the pgm-catalysed metathesis of olefins, he gave illustrations of new developments. In a lecture entitled ‘New Thermally Stable Catalysts via Encapsulation of Metal Nanoparticles in MeOx Empty Spheres’, M. Paul, M. Comotti, P. Arnal, P. Bazula and F. Schüth (Max-PlanckInstitut für Kohlenforschung, Mülheim an der Ruhr, Germany) outlined an elegant synthesis of metal particles such as gold nanoparticles in a ZrO2 hollow sphere. The Au nanoparticles are covered by SiO2, which is then coated with ZrO2. The SiO2 can be removed chemically. The remaining ZrO2 with encapsulated Au is thermally stable, and the Au particles are protected from sintering. The method can also be used for other precious metals such as platinum and palladium. M. Beller (Leibniz-Institut für Katalyse e.V., Universität Rostock, Germany) gave a lecture on ‘Homogeneous Catalysis – A Key Technology for the 21st Century’. As examples of topics success-


fully addressed, in terms of both fundamental research and technical application, Beller cited Pd-catalysed C–C coupling reactions and atomefficient carbonylations.

Poster Contributions G. Incera Garrido, F. C. Patcas, G. Upper, M. Türk and B. Kraushaar-Czarnetzki (Universität Karlsruhe, Germany), presented a poster entitled: ‘Preparation of Pt/SnO2 Supported Catalysts for the CO-Oxidation: Comparison between Classical and Supercritical Pt Deposition’. The catalyst, prepared via supercritical carbon dioxide (scCO2) deposition of Pt, oxidised CO at 80ºC with remarkable activity, whereas the catalyst made via conventional aqueous preparation shows no activity below 150ºC. S. Kureti and F. J. P Schott (Universität Karlsruhe) presented a poster about ‘Reduction of NOx by H2 on Pt Containing Catalysts in Diesel Exhaust’. The preferred techniques to meet emission standards are NOx storage catalyst (NSR) and selective catalytic reduction (SCR), using NH3 as reductant. However, a serious constraint on these technologies is that efficient NOx conversion is only achieved above 150ºC. The European Commission Motor Vehicle Emissions Group (MVEG) (2) estimates that the exhaust temperature of diesel passenger cars is below 150ºC for about 60% of the time, indicating a need for a technique to convert NOx in the low temperature range. The reduction of NOx by H2 on Pt catalysts is considered to be a promising method. However, it is well known that the H2/NOx reaction on classical Pt/Al2O3 gives N2O. To obtain selective production of N2, the catalyst was modified. The best catalyst so far gave 80% selectivity to N2. A. Boonyanuwat, A. Jentys and J. A. Lercher (Technische Universität München, Germany) reported on: ‘Hydrogen Production by Aqueous-

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Phase Reforming of Glycerol on Supported Metal Catalysts’. Platinum and palladium on alumina show the best selectivities to hydrogen (greater than 90%), while rhodium also gave alkane selectivity. A stability test was carried out for two weeks at 498 K and 29 bars. During this time, the activity of the catalysts was almost constant.

Concluding Remarks In summary, the meeting in Weimar, the beautiful city of Goethe and Schiller, covered the whole range of heterogeneous and homogeneous catalysis from fundamental studies to industrial catalysis. The 41. Jahrestreffen Deutscher Katalytiker will again take place in Weimar, from 27th to 29th February 2008 (3).


References 1

2 3

40. Jahrestreffen Deutscher Katalytiker, DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V.: http://events.dechema.de/katalytiker07.html Enterprise, Automotive Industry, MVEG: http://ec.europa.eu/enterprise/automotive/mveg_ meetings/index.htm 41. Jahrestreffen Deutscher Katalytiker, DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V.: http://events.dechema.de/katalytiker08.html

The Reviewer

Thomas Ilkenhans is a Research Chemist in the Gas Phase Catalysis Group at the Johnson Matthey Technology Centre. He is interested in using palladium in catalysis.

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DOI: 10.1595/147106707X235133

“Metal-catalysis in Industrial Organic Processes” EDITED BY G. P. CHIUSOLI (University of Parma, Italy) and P. M. MAITLIS (The University of Sheffield, U.K.), RSC Publishing, Cambridge, U.K., 2006, 290 pages, ISBN 978-0-85404-862-5, £99.95, U.S.$189.00

Reviewed by Robin B. Bedford School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.; E-mail: [email protected]

“Metal-catalysis in Industrial Organic Processes” fills the gap in the market between textbooks on homogeneous or heterogeneous catalysis and treatises on particular processes, typically available in the form of specialist reviews. It is pitched as an “advanced general textbook for chemistry students and their teachers; it will also be welcomed by researchers in industrial and Government laboratories”. In my opinion these target audiences are very well catered for by this excellent textbook. The field of industrial catalysis is obviously enormous and yet has been well covered here in fewer than 300 pages. This makes the book an accessible work that describes many of the more important processes in sufficient depth, rather than an unwieldy tome. The introduction (P. Howard, G. Morris and G. Sunley) gives a good overview of the general principles of catalysis in the industrial sector. These include the scales of various processes and factors that affect process development, such as economics, feedstock availability, safety and environmental considerations. Chapter 2 (M. G. Clerici, M. Ricci and G. Strukul) covers the formation of carbon–oxygen bonds by oxidation, beginning with the basic interactions of oxygen with transition metal centres. It then focuses on large-scale commercial applications such as the formation of adipic acid, terephthalic acid, ethylene oxide and phenols. Asymmetric epoxidation and dihydroxylation reactions are explored with regard to their application to the synthesis of fine chemical and pharmaceutical intermediates. Chapter 3 (L. A. Oro, D. Carmona and J. M. Fraile) covers hydrogenation reactions, beginning with an overview of homogeneous and heterogeneous reaction pathways. The industrial


application of heterogeneous catalysis focuses on the hydrotreating of petrochemicals, the hydrogenation of fats and the reduction of adiponitrile. Asymmetric homogeneous hydrogenation is covered in depth. Specific industrially important examples are given, including the syntheses of L-DOPA, (S)-metolachlor and (–)-menthol, all using rhodium-based catalysis. The next chapter (P. Maitlis and A. Haynes) describes industrial processes based on carbon monoxide. The first of the three main areas covered is the synthesis of acids and anhydrides from alcohol carbonylation reactions. The historical development of acetic acid synthesis leads on to the growth of the Monsanto (1) and BP CativaTM (2) processes using rhodium and iridium respectively. Similarly, the section on hydroformylation covers the development of the cobalt-catalysed process through to the use of rhodium-based systems, with a concise description of asymmetric hydroformylation. The final part of the chapter focuses on the FischerTropsch reaction. Chapter 5 (F. Calderazzo, M. Catellani and G. P. Chiusoli) describes C–C bond-forming reactions. This starts with the use of Lewis acid catalysis in the alkylation of aromatic compounds and then progresses to palladium-catalysed coupling reactions. Industrially significant examples are given, including the synthesis of sartans for the pharmaceutical industry and the fungicide boscalid, this is followed by a particularly informative discussion on why palladium-catalysed cross-coupling reactions have not made the inroads into the industrial sector that might be expected. The next section of the chapter details the use of allylic substrates in industrial catalysis. This chapter also includes the oligomerisation of alkenes, for instance in the synthesis of alkenes

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for the Shell Higher Olefins Process (SHOP), as opposed to olefin polymerisation which is covered in depth in a later chapter (Chapter 7) by G. Fink and H.-H. Brintzinger. The SHOP process itself is covered in Chapter 6 (C. L. Dwyer) which details the metathesis of olefins, with ruthenium catalysis prominent. This chapter also describes emerging technologies that are likely to impact on future applications of metathesis in the commercial sector.

Concluding Remarks Given that most readers’ interests will tend to lie either with homogeneous or heterogeneous catalysis, the provision of two appendices on organometallic chemistry and catalysis, and on basic concepts of surface science related to heterogeneous catalysis, is invaluable. An appendix on the kinetics of catalysis would have been useful as this is an area that is unfortunately not addressed to any great extent in the book. In general the text is liberally supported by the use of ‘boxes’ and annexes that detail interesting asides, important concepts or emergent technologies. A particularly appealing aspect of the book is the inclusion of ‘discussion points’ throughout the


text. These would be useful, for instance, as themes for round-table discussions with advanced level undergraduate and postgraduate students, indeed I have used some of them for precisely this purpose. In some of the chapters these are supplemented with invaluable extra ‘hints’ to help get the ball rolling. In summary I wholeheartedly recommend this excellent textbook to anybody with an interest in catalysis, either from an industrial or academic perspective.

References 1 2

J. F. Roth, Platinum Metals Rev., 1975, 19, (1), 12 J. H. Jones, Platinum Metals Rev., 2000, 44, (3), 94

The Reviewer Having graduated in biochemistry from the University of Sussex, U.K., Robin Bedford undertook a D.Phil. in organometallic catalysis with Penny Chaloner (also at Sussex). He then held a postdoctoral research associateship with Anthony Hill at Imperial College London and lectureships in inorganic chemistry at Trinity College, Dublin and the University of Exeter, where he was promoted to Reader in Catalysis. He moved to the University of Bristol in a similar role in 2005. He currently holds an EPSRC Advanced Research Fellowship and the Royal Society of Chemistry’s Sir Edward Frankland Fellowship (Dalton Division) for 2006/7.

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DOI: 10.1595/147106707X232893

Building a Thermodynamic Database for Platinum-Based Superalloys: Part II USE OF MODELS REQUIRING FEWER PARAMETERS By A. Watson* Institute for Materials Research, University of Leeds, Leeds LS2 9JT, U.K.; *E-mail: [email protected]

R. Süss** Advanced Materials Division, Mintek, Private Bag X3015, Randburg 2125, South Africa, DST/NRF Centre of Excellence in Strong Materials, Johannesburg 2050, South Africa, and School of Chemical and Materials Engineering, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa; **E-mail: [email protected]

and L. A. Cornish† Advanced Materials Division, Mintek, Private Bag X3015, Randburg 2125, South Africa, DST/NRF Centre of Excellence in Strong Materials, Johannesburg 2050, South Africa, and School of Chemical and Materials Engineering, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa; †E-mail: [email protected]

Work is being done at Mintek, the University of Leeds and the University of Bayreuth to build up a platinum-aluminium-chromium-ruthenium (Pt-Al-Cr-Ru) database for the prediction of phase diagrams for further alloy development by obtaining good thermodynamic descriptions of all of the possible phases in the system. Binary descriptions were combined, allowing extrapolation into the ternary systems, and experimental phase equilibrium data were compared with calculated results. Very good agreement was obtained for the Pt-Al-Ru system, as described in Part I of this series of papers (1). This paper (Part II) addresses the Pt-Cr-Ru system, with equally encouraging results. The final paper in the series (Part III, to be published in a future issue of Platinum Metals Review) will deal with work on the platinum-aluminiumchromium-nickel (Pt-Al-Cr-Ni) database at the University of Bayreuth. The Pt-Al-Cr-Ru and Pt-Al-Cr-Ni databases will eventually be merged.

Work has been ongoing in building a thermodynamic database for the prediction of phase equilibria in Pt-based superalloys (1–5). The alloys are being developed for high-temperature applications in aggressive environments. The database will aid the design of alloys by enabling the calculation of the composition and proportions of phases present in alloys of different compositions. Currently, the database contains the elements platinum, aluminium, chromium and ruthenium. This paper is a revised account of work presented at the conference: Southern African Institute of Mining and Metallurgy ‘Platinum Surges Ahead’ at Sun City, South Africa, from 8th to 12th October 2006 (5).


Part I, describing initial results for the Pt-Al-Ru system from the compound energy formalism model, was published in the July 2007 issue of Platinum Metals Review (1). For the Ru-Al system, very good agreement has been obtained between experimental phase equilibrium data and calculations based on a version of the compound energy formalism model (1). However, for the other binary and ternary systems, there are insufficient data to obtain good results by this method, since more phases are represented in each system. This paper (Part II) describes the different approach which was needed, with simpler representation to allow for sparse data.

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Part III will complete the series by describing work at the University of Bayreuth on the platinum-aluminium-chromium-nickel (Pt-Al-Cr-Ni) database, which is eventually to be merged with the Pt-Al-Cr-Ru database.

Simple Phase Representation: General Considerations Concerning the (Pt) and Pt3Al phases, there is disagreement on which particular model should be used. These phases are similar to (Ni) and Ni3Al respectively. (Here, (Pt) and (Ni) denote combinations of four atoms of the elements in the four-compound sublattice formalism (CSF); arithmetically, Pt4 and Ni4 respectively.) One school of thought states that as all four phases are based on the f.c.c. lattice, then Ni3Al, which can be viewed as an ordered f.c.c. phase, should be included as the f.c.c. phase in modelling (Pt) and Pt3Al. On the other hand, another school of thought stipulates that, since (Pt) and Pt3Al solidify separately, they should be modelled separately. The second school of thought would allow for Pt3Cr and PtCr to be modelled as part of (Pt), since they form by ordering within the (Pt) phase field at lower temperatures. This might be considered as anomalous in that Pt3Al would not be incorporated in the f.c.c. model, whereas Pt3Cr would be. However, given that phases should be modelled in the same way only if they are likely to be contiguous, this would not be a problem unless Pt3Al is likely to be contiguous with Pt3Cr. At the moment, this is not likely. A similar argument can be made for Pt3Al, which just like Ni3Al, solidifies as a separate phase from (Pt), and is not formed within. Another source of contention is that in the model being developed here, many parameters are needed to describe the phase. For the Ni-Al system, it could be argued that there are many data points and that the large number of parameters is justified. However, for Pt-Al, not only are there fewer data points, but there is also much greater uncertainty in the binary phase diagram regarding the reaction temperatures involving Pt3Al, and even the type of ordering. Thus, a much simpler model is prescribed for the Pt3Al phase, both because of a dearth of data (as compared with


Ni3Al), and also because the Pt3Al and (Pt) phases solidify separately. All the information regarding ordering needs to be gathered before any incorporation into modelling is attempted. However, it must be noted that in the Dupin database (6), the Ni3Al phase is modelled as ordered f.c.c., even though it solidifies separately. The latest database from Dupin (6) was used to draw the Ni-Al phase diagram, and the γ/γ' boundary did not agree well with that in the experimental phase diagram, so it is questionable whether Dupin’s complex modelling is really worthwhile. It is best to adopt the most appropriate model for each phase in the system on the basis of its crystal structure and the available experimental data. Simple substitutional solid solutions can be modelled with two sublattices; one sublattice of sites of mixed occupancy (by the substituting elements) and one of interstitial sites. Ordered phases have a more complex crystallography in that atoms have preferential site occupancy. These phases are modelled with a more complex sublattice model comprising multiple sublattices with mixing of a number of different elements on each, depending on the crystallography. Although a multiple sublattice model is more complex than a simple two-sublattice model, it is easier to use the former to describe phases with a limited homogeneity range. In the extreme case, a stoichiometric phase is thus modelled with a single component on each sublattice. It is often useful to model an ordered phase along with its disordered ‘parent’ phase, for example b.c.c._B2 and b.c.c._A2, or f.c.c._L12 and f.c.c._A1, with a single Gibbs energy description enabling the ordering transition to be modelled. This modelling is quite complex, and whether such complications should be included depends on the application of the database. There are databases being developed without such complex modelling and these are very useful. One example is the COST 531 lead-free solders database (7), comprising assessed thermodynamic data for binary and ternary systems based on eleven elements associated with lead-free solder materials. Thus, it might be questioned whether the current pgm database should be concerned with order/disorder reactions. The answer should be positive, of

190

course, because the ordered Pt3Al phase, which is an ordered f.c.c. phase, is the basis of the alloys. However, if there are too few experimental data available, modelling the Pt3Al and f.c.c._A1 phase with a single Gibbs energy description will be difficult. If a model requiring many parameters is optimised with few data points, the parameters themselves become meaningless and the results are highly unlikely to be representative. Thus, in the current work, it was decided to model such ordered phases separately and then extend the database subsequently if there is both sufficient need and the experimental data become available. In this way, the database grows with the available experimental data, and at any time, the database is the optimum that can be achieved. Currently, the database is being developed so that the phase equilibria between the phases on solidification can be derived. As more work is done on developing the alloys for application, the order/disorder reactions will become increasingly important, especially for the Pt3Al phase. A combination of Thermo-CalcTM (8), Pandat (9) and MTDATA (10) software was used for the present work.

Chromium-Platinum Until experimental results show otherwise, the assessment of Oikawa et al. (11) will be used, extrapolated into the ternary, and will then be reoptimised with experimental values from the PtCr-Ru system. The assessment of Oikawa et al. (11) Fig. 1 Cr-Pt phase diagram calculated by Oikawa et al. (11) (Courtesy of Elsevier Science; reference numbers are as cited in Reference (11))

is shown in Figure 1. However, it was necessary to derive Gibbs energy parameters for the metastable h.c.p. phase in the binary system. The metastable phase was initially allocated the same set of Gibbs energy values as for the f.c.c. phase, but the parameters were optimised using the ternary data (described below).

Platinum-Ruthenium It was initially thought that the description of PtRu in the Spencer database (12) version of Pt-Ru would be the same as that in the Scientific Group Thermodata Europe (SGTE) database (13). However, this was not so. The phase diagram from Spencer is a eutectic, with a maximum in (Pt) and ~ 10ºC between the maximum and eutectic temperature, whereas that from SGTE is peritectic, which is consistent with available literature (14, 15) and experimental work at Mintek. Optimising with data from Hutchinson (14) gave a good fit and convincing coefficients. While plotting the free energy curves demonstrated that Ru had an unusual energy curve, it would be unwise to change this feature, because it originated from the Ru unary data, is set across the entire database, and represents a best-fit value for many systems. One solution to this anomaly would be to add an interaction parameter, but it must be remembered that there are too few data available. However, it was found that the most reasonable fit to the phase boundaries of the (Pt) + (Ru) two-phase field,

2000 Liquid

Temperature, ºC

1800

Müller [51]

1600

Waterstrat [52] 1400

Waterstrat [52]

1200

f.c.c.

1000 b.c.c. 800


Cr3Pt

0

20

40

60 Pt, at.%

80

100

191

where a few compositions had been measured experimentally, resulted in the appearance of a very shallow eutectic reaction. The phase diagram, optimised using WinPhaD and calculated using Pandat, is given in Figure 2, and may be compared with the experimental diagram in Figure 3.

have three sublattices, so this format would be followed for the Cr-Ru system despite the fact that, especially given such limited data, it would be difficult to have mixing on all three sublattices – many end-members would be needed. It was therefore decided that Cr only would be located on one sublattice, and the remaining two would have mixing; this is normal practice. The current model of choice for the σ phase is 10:16:4 (where the notation shows the numbers of atoms on each of the three

Chromium-Ruthenium This system contains two intermetallic compounds: Cr2Ru (σ) and Cr3Ru. The accepted models

Fig. 2 Pt-Ru phase diagram: Best calculated diagram to date

3000 Liquid

Temperature, ºC

2500

2000 h.c.p._A3 1500

f.c.c._A1

1000

500 0

2400

0.1

0

0.2

0.3 0.4 0.5 0.6 0.7 Ru, mole fraction

10

0.8

Ru, wt.% 30 40 50

20

0.9

1

70

100 2334ºC

2200

Fig. 3 Pt-Ru phase diagram: Experimental from (15) (Courtesy of ASM International)

Liquid

Temperature, ºC

2000 1800

79

70 1769.0ºC

1600 (Pt)

(Ru)

1400 1200 1000

80

62

0

10

20


30

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50 60 Ru, at.%

70

80

90

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192

sublattices; the previous model was 8:18:4). The previous model featured in the Glatzel assessment (16), although with mixing on all three sublattices. Elements are usually mixed on many sublattices only where there is a very wide range of phase stability. In this case, there is a narrow phase stability range, so the degree of mixing needs to be reduced. The approach used was to build up the system with the most simple phase diagram descriptions possible: thus Cr2Ru (σ) and Cr3Ru would be line compounds. The Ru and Cr unary data were derived from Kaufman (17). Since Kaufman’s (17) reported reaction temperatures involving Cr2Ru (σ) and Cr3Ru were suspiciously convenient: ~ 750, ~ 800 and ~ 1000ºC, it was realised that there were problems with the system, and the rounded data are the best that were obtained from the literature (15). These had to be used, as there are no other data available. Attempts to measure the reaction temperatures by differential thermal analysis (DTA) were inconclusive (18). The phase diagram gave a very good fit, as shown in Figure 4, compared with the experimental diagram (Figure 5) (15).

Platinum-Chromium-Ruthenium Experimental results of the A15 Cr3Ru and Cr3Pt phases were not conclusive in showing whether the phases are contiguous, despite two Fig. 4 Cr-Ru phase diagram: Best calculated diagram to date

more samples of intermediate compositions between Cr3Ru and Cr3Pt being prepared at Mintek. These samples were annealed at ~ 850ºC, because if the phases are contiguous, they should meet at this temperature for the sample compositions chosen. Depending on how the phases extend into the ternary, the sublattice on which substitution is occurring can be determined. For Cr3Ru, if Ru is constant, then Pt substitutes for Cr; and for Cr3Pt, if Cr is constant, Ru substitutes for Pt. It must, however, be remembered that the original samples were not in equilibrium, and the latest samples were annealed for longer, to promote equilibrium. It should be noted that Waterstrat’s Cr3Pt phase (19) was more narrow (almost stoichiometric) and did not decompose at lower temperature (which is what was calculated at one stage in the present work). A likely model for this case (19) would be Cr on one sublattice and Pt + Cr on the other, but this depends on the atomic sizes. These can be measured in different ways (giving different results) and the most appropriate method should be used for the mode of bonding of the particular atom. Pt and Ru show similar covalent radii. This being so, they could sit on the same sublattice. However, it is recommended that other A15 phases be researched to see how they would best be modelled, especially for the composition

3000

Liquid

Temperature, ºC

2500

2000

1500

b.c.c._A2

h.c.p._A3 +Cr2Ru

h.c.p._A3

1000

500


Cr3Ru 0

0.1

0.2

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0.8

0.9

1

193

2500

0 10 20 30 40

Ru, wt.% 60 70

50

80

90

100 2334ºC

Fig. 5 Cr-Ru phase diagram: Experimental from (15) (Courtesy of ASM International)

Liquid 1863ºC ~ 37 1610ºC 1580ºC ~ 48

~ 32

1500

(Ru)

(Cr) ~ 23

1000

500

σ

0

10

~ 1000ºC

20

Cr3Ru

Temperature, ºC

2000

~ 33

30

~ 800ºC ~ 750ºC

40

50 60 Ru, at.%

ranges (i.e. the spread on both sides from mole fraction X = 0.25). For the representation of Cr3Pt within the ternary (and higher-order phase diagrams), the model would be much simpler (and have fewer end members) if the lattice components could be described as (Cr, Cr) (Cr, Pt, Ru). To model the ternary system, an interaction parameter, added to increase the phase extensions into the ternary, was determined for the h.c.p. phase. The projected liquidus surface, shown in Figure 6, is an improvement on the assessment by Glatzel et al. (16). However, the invariant reactions are still incorrect, because Figure 6 shows the liquidus surfaces for (Ru) and Cr3Pt abutting, by contrast with the experimental results in Figure 7. Those for (Cr) and (Pt) should in fact abut, because of the (Pt) + (Cr) eutectic observed in the ternary samples (20, 21). However, the junction between the incorrect surfaces of primary solidification is smaller than was calculated previously (16), and agrees more closely with the experimental results. The thermodynamic description of the ternary system was optimised using the experimental data of Zhao (22), as this set of data seemed to be more complete and self-consistent, and Mintek’s data (20, 23) were affected by coring. The assessment module of MTDATA was used to perform the optimisation. During the optimisation process it


70

80

90

100

was found that it was necessary to adjust only the Gibbs energy description of the metastable h.c.p. phase in the Cr-Pt binary in order to get a reasonable fit to the experimental phase diagram data for the f.c.c. and h.c.p. phase boundaries. No ternary interactions were required for these phases (24). The experimental data for the A15 phase fitted reasonably well, although the fit was little improved by allowing the optimisation to give a Gibbs energy description for the metastable Pt3Ru A15 phase. The A15 phase extends from the Cr-Pt edge as required but too far into the ternary. Also, the A15 phase field is not wide enough as it extends into the ternary. This feature is probably due to the fact that the phase is modelled with a very narrow homogeneity range in the Cr-Ru system. Better modelling of the A15 phase in the binary system would undoubtedly improve the overall modelling of this phase, but this would require further experimental study of its stability range. The fit to the experimental b.c.c. phase diagram data is, however, very good. The calculated phase diagram for 1200ºC, showing the experimental data, is given in Figure 8. The fit with the experimental data from Süss et al. (23) is not so good, particularly with respect to the (Ru) h.c.p. phase boundary, but this could be due to coring effects. Again, this could be improved by a better description of the A15 phase.

194

Ru 1

0.6

Ru

,m

ole

fr a cti on

0.8

0.4

0.2

Cr 0

Pt 0.2

0.4 0.6 Pt, mole fraction

0.8

1

Fig. 6 Liquidus surface for the Pt-Cr-Ru system: Best calculated surface to date Ru (Ru)

L + (Ru) → (Pt) at 2100ºC

(Ru) L → (Ru) + (Cr) at 1610ºC (Pt) 1 (Cr) 2 Cr

Cr3Pt

L → Cr3Pt + (Cr) at 1500ºC

Pt L → Cr3Pt + (Pt) at 1530ºC

Fig. 7 Liquidus surface for the Pt-Cr-Ru system: Experimental from (20, 21) (Courtesy of Elsevier Science and the African Materials Research Society). Reaction 1: L + (Ru) ↔ (Pt ) + (Cr); Reaction 2: L + (Cr) ↔ (Pt ) + Cr3Pt


195

The calculated phase diagram for 1000ºC is given in Figure 9.

database can only be undertaken once more experimental data have been acquired. Work is in hand at the University of Bayreuth on the platinum-aluminium-chromium-nickel (PtAl-Cr-Ni) database, which is eventually to be merged with the Pt-Al-Cr-Ru database. Part III of this series of papers, to be published in a future issue of Platinum Metals Review, will describe this work.

Conclusion The latest developments to the Pt-Al-Cr-Ru database have improved the agreement with the experimental phase diagrams, and especially with diffusion data. The models of the f.c.c., Cr3Ru and Cr2Ru (σ) phases were changed, and the new models were selected so that fewer parameters were necessary. However, the order/disorder reactions of the f.c.c. phases have yet to be modelled successfully, and before this can be realised more experimental data are needed. The A15 phase needs to be modelled in order to produce a wider phase range within the ternary. Once again, more experimental data are needed to confirm whether the A15 phases in the Cr-Pt and Cr-Ru systems are contiguous. More samples between the two binary phases had been manufactured, annealed at intermediate temperatures and analysed, but the results were not conclusive. Thus, future work on the

Acknowledgements Financial assistance from the South African Department of Science and Technology (DST); the Platinum Development Initiative (PDI: Anglo Platinum, Impala Platinum and Lonmin); DST/NRF Centre of Excellence in Strong Materials; and Engineering and Physical Sciences Research Council (EPSRC) Platform Grant GR/R95798 is gratefully acknowledged. The authors would like to thank CompuTherm LLC, Wisconsin, U.S.A., and the National Physical Laboratory (NPL), Teddington, U.K., for the

Pt

0.8

0.2 f.c.c. h.c.p. A15 b.c.c.

Pt,

0.4

0.6

0.2

on cti fra

mo le

ole

fra cti

0.4

,m

0.6

Ru

on

f.c.c._A1

0.8 A15

h.c.p._A3

b.c.c._A2

Cr

0.8

0.6 0.4 Cr, mole fraction

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Fig. 8 Calculated isothermal section for the Pt-Cr-Ru system for 1200ºC with experimental data from Zhao (22) (Courtesy of Springer)


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Fig. 9 Calculated isothermal section for the Pt-Cr-Ru system for 1000ºC with experimental data from Süss et al. (23) (Courtesy of Elsevier Science)

provision of the WinPhaD, Pandat and MTDATA software. This paper is published with the permission of Mintek and the Southern African Institute of Mining and Metallurgy.

References 1 L. A. Cornish, R. Süss, A. Watson and S. N. Prins, Platinum Metals Rev., 2007, 51, (3), 104 2 I. M. Wolff and P. J. Hill, Platinum Metals Rev., 2000, 44, (4), 158 3 L. A. Cornish, J. Hohls, P. J. Hill, S. Prins, R. Süss and D. N. Compton, J. Min. Metall. Sect. B: Metall., 2002, 38, (3–4), 197 4 L. A. Cornish, R. Süss, L. H. Chown, S. Taylor, L. Glaner, A. Douglas and S. N. Prins, ‘Platinum-Based Alloys for High Temperature and Special Applications’, in “International Platinum Conference ‘Platinum Adding Value’”, Sun City, South Africa, 3rd–7th October, 2004, Symposium Series S38, The South African Institute of Mining and Metallurgy, Johannesburg, South Africa, 2004, pp. 329–336


5 L. A. Cornish, R. Süss, A. Watson and S. N. Prins, ‘Building a Database for the Prediction of Phases in Pt-based Superalloys’, in “Second International Platinum Conference ‘Platinum Surges Ahead’”, Sun City, South Africa, 8th–12th October, 2006, Symposium Series S45, The Southern African Institute of Mining and Metallurgy, Johannesburg, South Africa, 2006, pp. 91–102; http://www.platinum.org.za/Pt2006/index.htm 6 B. Sundman and N. Dupin, in: “XXIX JEEP: Journées d’Étude des Équilibres entre Phases”, Lyon Villeurbanne, France, 2nd–3rd April, 2003, eds. F. Bosselet, C. Goutaudier et al., Journal de Physique IV – Proceedings, EDP Sciences, Les Ulis, France, 2006 7 A. Watson, A. Dinsdale, A. Kroupa, J. Vízdal, J. Vrestal and A. Zemanová, “The COST 531 Leadfree Solders Thermodynamic Database”, Proceedings of the 61st Annual ABM Congress, Rio de Janeiro, Brazil, 24th–27th July, 2006 8 B. Sundman, B. Jansson and J.-O.Andersson, CALPHAD, 1985, 9, (2), 153 9 S.-L. Chen, S. Daniel, F. Zhang, Y. A. Chang, X.-Y. Yan, F.-Y. Xie, R. Schmid-Fetzer and W. A. Oates, CALPHAD, 2002, 26, (2), 175

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10 R. H. Davies, A. T. Dinsdale, J. A. Gisby, J. A. J. Robinson and S. M. Martin, CALPHAD, 2002, 26, (2), 229 11 K. Oikawa, G. W. Qin, T. Ikeshoji, O. Kitakami, Y. Shimada, K. Ishida and K. Fukamichi, J. Magn. Magn. Mater., 2001, 236, (1–2), 220 and references therein 12 P. J. Spencer, The Noble Metal Alloy (NOBL) Database, The Spencer Group, Trumansburg, U.S.A., 1996 13 A. T. Dinsdale, CALPHAD, 1991, 15, (4), 317 14 J. M. Hutchinson, Platinum Metals Rev., 1972, 16, (3), 88 15 “Binary Alloy Phase Diagrams”, 2nd Edn., eds. T. B. Massalski, H. Okamoto, P. R. Subramanian and L. Kacprzak, in 3 volumes, ASM International, Ohio, U.S.A., 1990 16 U. Glatzel and S. N. Prins, ‘Thermodynamic Assessments of the Pt-Cr and Cr-Ru Systems with an Extrapolation into the Pt-Cr-Ru System’, in “CALPHAD XXXII: Program and Abstracts”, Quebec, Canada, 25th–30th May, 2003, p. 118; see C. K. Pollard, CALPHAD, 2004, 28, (3), 241 17 L. Kaufman and H. Bernstein, “Computer Calculation of Phase Diagrams, with Special

18

19 20 21

22 23

24

Reference to Refractory Metals”, Academic Press, New York and London, 1970, p. 60 R. Süss and L. A. Cornish, ‘Possible Changes to the Cr-Pt Binary Phase Diagram’, in Proc. Microsc. Soc. south. Afr., Vol. 35, Kwazulu-Natal, 5th–7th December, 2005, p. 9 R. M. Waterstrat, J. Less Common Met., 1981, 80, (1), P31 R. Süss, L. A. Cornish and M. J. Witcomb, J. Alloys Compd., 2006, 416, (1–2), 80 R. Süss, U. Glatzel, S. N. Prins and L. A. Cornish, ‘A Comparison of Calculated and Experimental Liquidus Surfaces for the Pt-Cr-Ru System’, in Second International Conference of the African Materials Research Society, University of the Witwatersrand, Johannesburg, 8th–11th December, 2003, pp. 141–142 J.-C. Zhao, J. Mater. Sci., 2004, 39, (12), 3913 R. Süss, L. A. Cornish and M. J. Witcomb, ‘Investigation of Isothermal Sections at 1000 and 600ºC in the Pt-Cr-Ru System’, J. Alloys Compd., in press A. Watson, L. A. Cornish and R. Süss, Rare Met., 2006, 25, (5), 597

The Authors Dr Andy Watson is a Senior Research Fellow in the Institute for Materials Research at the University of Leeds. He has worked in experimental and computational thermodynamics for many years and has interests in lead-free solders and intermetallic phases as well as pgm alloys.

Rainer Süss is Section Head of the Advanced Metals Group in the Advanced Metals Division at Mintek, as well as the co-ordinator of the Strong Metallic Alloys Focus Area in the DST/NRF Centre of Excellence for Strong Materials. His research interests include phase diagrams, platinum alloys and jewellery alloys.

Lesley Cornish is the Director of the DST/NRF Centre of Excellence in Strong Materials and an Honorary Professor at the University of the Witwatersrand, South Africa. She is associated with Mintek. Her research interests include phase diagrams, platinum alloys and intermetallic compounds.


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DOI: 10.1595/147106707X234242

The 21st Santa Fe Symposium on Jewelry Manufacturing Technology TECHNICAL INTEREST IN PALLADIUM REMAINS STRONG IN THE INDUSTRY Reviewed by Christopher W. Corti COReGOLD Technology Consultancy, Reading, U.K.; E-mail: [email protected]

The 21st annual Santa Fe Symposium® was held in Albuquerque, New Mexico, from 20th to 23rd May 2007 (1). Yet again, this well-attended international symposium covered a wide range of technical topics but the strongest interest was in palladium as a jewellery material (see also (2)). There is no doubt that palladium jewellery is causing excitement in the manufacturing industry and, as delegates heard in discussion, there is increasing recognition that palladium is quite different in its manufacturing behaviour from platinum. The Symposium commenced with a thoughtprovoking keynote presentation by Andrea Hill (CEO, The Bell Group, U.S.A.), entitled ‘Top Line Focus’, in which she discussed the business-led approach to running a jewellery manufacturing firm. The three key themes were: (a) knowing your business, (b) revenue numeracy and (c) attention to planning. The technical sessions followed, firstly with Chris Corti (COReGOLD, U.K.) introducing ‘Basic Metallurgy of the Precious Metals’ to the delegates, and discussing the metallurgical basis for the various precious metal jewellery alloys, including those of platinum and palladium, and how alloy properties can be tailored by composition and microstructure to suit the application or manufacturing route.

Palladium Mark Mann (Mann Design Group, U.S.A.) spoke on ‘950 Palladium: Manufacturing Basics for Servicing, Assembly and Finishing’. He started his presentation by discussing the basic properties of palladium that make it attractive as a jewellery metal and how to distinguish it from platinum and white gold, using the non-destructive iodine test (3). He then launched into a comprehensive review of the working behaviour of palladium in relation


to general jewellery manufacturing. He covered the practical aspects of annealing, contamination, soldering and welding (by torch and laser), forming and shaping, engraving, finishing and setting. The presentation was supported by a number of case studies of hand techniques, such as ring sizing. While palladium solders are available, he demonstrated that low-melting platinum-based solders could be used. The information presented in this paper will form the basis of a new jewellery technical manual being produced by Johnson Matthey for the industry (3). The welding of palladium was further discussed in a presentation by Kevin Lindsey (Lindsey Jewelers, U.S.A.), entitled ‘How To Get the Best Results Welding Palladium: A Comparative Study’. This was the result of a study of the tungsten inert gas (TIG) welding of two 950 palladium alloys, from Johnson Matthey and Hoover & Strong, in which several welding parameters were varied. The model configuration for the test welds was a ring shank, 4 mm × 1.5 mm. The welds were tested by bending to failure. Two tungsten electrode sizes were tested and pure argon was used as the cover gas. Copper plate was used as the welding substrate. Depending on welding conditions, some cratering and poor penetration were obtained in some test welds, but good welds could be obtained in both palladium materials under the correct conditions. The Johnson Matthey alloy performed better in terms of cycles of bending to failure, attaining 94% of the cycles to failure of the unwelded bar stock. The Hoover & Strong alloy showed better flow during welding, but poorer performance in terms of cycles to failure (70% of bar stock). The optimal welding parameters depend on the alloy. Lindsey gives a set of starting values suitable for both alloys which will give

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reasonable initial welds and serve as a basis for optimisation. The overall conclusion is that 950 palladium alloys can be satisfactorily joined by TIG welding. A comparative study of the manufacture of findings was presented by Fred Klotz (Hoover & Strong, U.S.A.): ‘A Comparison of Nickel White Gold, Palladium White Gold and 950 Palladium in the Manufacture of Findings’. He compared the performance of 950 palladium with those of 14 carat and 18 carat nickel- and palladium-white golds and 950 platinum-ruthenium alloys for the manufacture of both die-struck and cast settings. He noted that both the 950 platinum and palladium alloys showed a comparable degree of whiteness (as measured by the ASTM Yellowness Index (4, 5)), and better whiteness than the Grade 1 white golds used in the study. The cold forging tests were performed on wire stock, 0.1 inch diameter, in conventional steel dies, using conditions optimised for the white golds. Klotz noted that all alloys cold-forged well, but that the platinumruthenium alloy performed not quite so well during blanking operations. In cold forging, metallography revealed the flow of metal around the edge into the overflow area. The 950 palladium alloy flowed well and annealed to a fine grain structure. In assembly tests, all the blanked settings assembled satisfactorily, although the platinum settings showed more drag as they slid together, probably due to their rougher sheared edges from blanking. The 950 palladium blanks were softer than the other alloys and more care had to be taken to stop them bending or distorting when pressure was applied. Soldering tests with a torch showed good solder flow for both palladium and platinum settings. Machining tests were conducted on wedding bands using polycrystalline diamond tools. As expected, the platinum alloy was the most difficult to machine. The palladium alloy was also found to be difficult compared with the gold alloys, when the same tool set-up as for platinum was used. In addition, investment casting tests on settings showed all alloys to cast well. Subsequent machine finishing revealed few defects and all alloys polished well.


Klotz concluded that both the platinum and palladium alloys perform differently from the golds, and processing needs to vary accordingly. The use of metallography in jewellery fabrication was discussed by Professor Paolo Battaini (8853 SpA, Italy) and illustrated by case studies of defects: ‘Metallography in Jewellery Fabrication: How to Avoid Problems and Improve Quality’. He demonstrated how it can be used to determine whether annealing has resulted in satisfactory recrystallisation for example. Of particular note was an instance of silicon contamination in a 950 palladium alloy during investment casting that caused intergranular embrittlement.

Platinum A review of casting tree design in the investment casting of platinum alloys was presented by Jurgen Maerz (Platinum Guild International, U.S.A.): ‘Platinum Casting Tree Design’. For many manufacturers of platinum jewellery, investment casting is something of a challenge. Maerz believes many of the problems with investment casting are associated with tree design and sprueing techniques and he set out to de-mystify the process. This presentation included sound advice on torch casting, where the metal is melted by gas torch, as well as the use of induction melting. He also discussed various casting machine characteristics before focusing on tree design – describing the ‘thick centre’ (central sprue) tree, the ‘no tree, button-casting’ design, the ‘diablo’ shaped tree, ‘four wheel’ or circular-sprued tree, thin-sprue trees and inverted trees. Maerz addressed shell casting and the tree/sprue design approach necessary for this method. In addition, he commented on the various platinum alloys and their performance in casting. Finally, Maerz discussed a rapid method of torch casting that he introduced in 1998 (6). Using investment powders derived from the dental industry, the entire casting process can be accomplished in less than one hour, using a Tbar tree design. Maerz’s review was certainly very comprehensive. It should benefit all casters of platinum jewellery and encourage new casters to work with platinum with some degree of confidence.

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A novel alloy development was the subject of a presentation by Boonrat Lohwongwatana (California Institute of Technology, U.S.A.): ‘Hard 18K and .950 Pt. Alloys That Can Be Processed Like Plastics or Blown Like Glass’. This concerned bulk metallic glasses, or ‘amorphous or liquid metals’ as they are known. In this study, Lohwongwatana has developed two bulk metallic glass (BMG) alloys for jewellery application (Figure 1). One is an 850 platinum containing copper, nickel and phosphorus; the other is a hard 18 carat gold. After describing BMGs and their characteristics, in particular their glass transition temperature and the need to cool rapidly to preserve the amorphous structure (there is a critical cooling rate), he went on to describe how such materials can be processed with reference to a time-temperature diagram and the onset of crystallisation. BMGs can be moulded by blowing, injection moulding or by thermoplastic forming. Shapes can also be obtained by casting, in which a crystalline structure can be obtained by cooling at less than the critical rate. Particular attention was given to thermoplastic processing in which BMG alloy grains (in the amorphous condition) are heated above the glass transition temperature to become a viscous liquid, then moulded in dies or by blow forming. For the platinum alloy, processing can be done at 250 to 270ºC. The processed alloy can be allowed to crystallise or cooled to maintain the BMG state. Enormous deformations can be obtained and interesting shapes can be made, with very good

surface detail and finish. This is a very innovative development, ready for commercial exploitation. It will be interesting to see how the jewellery industry responds. Under the title ‘Know Your Defects: The Benefits of Understanding Jewelry Manufacturing Problems’, Stewart Grice (Hoover & Strong, U.S.A.) discussed a number of case histories of manufacturing defects and how use of hardness testing, optical and electron microscopy and compositional analysis can be used to determine the causes of defects and thus lead to solutions to prevent recurrence. Among the many case histories discussed, Grice included one on surface porosity on a 950 platinum-ruthenium alloy investment cast ring. The casting had a frosted appearance and gas porosity was suspected. However, metallography of a cross-section revealed the cause as massive shrinkage porosity in the head and shoulder areas of the ring. Modifying the sprue and gating solved the problem. Another example on the same alloy involved embrittlement of mill stock made from scrap sprues and surplus castings. The bar had failed catastrophically after only two passes through the rolling mill. The intergranular failure was examined under the optical microscope and the presence of a second phase at the grain boundaries observed. Full chemical analysis revealed the presence of 100 ppm of phosphorus, an element well known to cause embrittlement of platinum at levels of 50 ppm or less. The source of the phosphorus was probably the phosphate-

Fig. 1 Thermoplastic forming of 850 platinum bulk metallic glass (BMG) from BMG pellets (Courtesy of B. Lohwongwatana)


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bonded investment mould material. Its presence would indicate inadequate removal from the casting scrap. Progress in optimising the burnout characteristics of resin patterns produced by rapid prototyping/manufacturing technologies, was discussed by Ian McKeer (SRS Ltd, U.K.), in terms of their use for direct investment casting: ‘Improvements in the Burnout of Resin Patterns’. Clean burnout of the resin has been a major problem. Casting, using platinum investments, showed some problems with surface quality. The fast ‘dental’ cycle approach, described by Maerz (see above) did produce some improvements.

Other Papers of Interest McKeer’s presentation was focused on product quality and two further presentations took up this theme. Alexandre Auberson (Cartier, U.S.A.) spoke about the testing of jewellery made by Cartier to ensure ‘fitness for purpose’: ‘Tests for Jewellery: A Must in the Development and Quality Process’. Appropriate testing is a ‘must’ for both product development and quality assurance. Auberson described a number of test methods and machines developed by Cartier to simulate inservice conditions for wear, strength, flexibility, mechanical shocks, durability and tarnish and corrosion among others. Of particular interest and amusement to the audience was Cartier’s ‘simulated handbag’ test, Figure 2, designed to simulate the effects of jewellery kept in a woman’s handbag; as Auberson remarked, it can reveal inherent weaknesses in jewellery construction. Chris Corti (COReGOLD, U.K.) took up the quality theme, assessing progress made by the industry over the ten years since he first addressed this topic and identified the need for industry-wide standards: ‘Quality in the Jewellery Industry Beyond 2000: A Review of Progress 1998–2006’. Appreciable progress has been made, for instance in adopting quality assurance schemes and defining white gold colour standards, but much remains to be tackled, such as industry-standard product test procedures, hallmarking standards and even basic alloy data sheets for the common alloys used in jewellery. Klaus Wiesner (Wieland GmbH, Germany)


spoke about sheet metal manufacturing of precious metals, and addressed some basics in terms of processing, defects and tolerances related to customer requirements: ‘Sheet Metal Manufacturing – Some Basics’. Greg Raykhtsaum (Leach & Garner, U.S.A.) revisited the topic of nickel testing of white gold and the amended EU Directive (7), showing how this modified regulation opens up new opportunities for nickelcontaining golds: ‘White Gold Piercing Jewelry and the “Nickel Directive”, 2004/96/EC’. There were several presentations on tarnish measurement, in relation to the new tarnish-resistant silvers on the market. The need for improved tarnish test standards and procedures was identified. This topic was also taken up by Dippal Manchanda (Birmingham Assay Office, U.K.), who discussed recent progress in amending the EU Directive, and the Assay Office’s development of a new, faster test procedure which is showing some promise as an alternative, accurate test: ‘Comparative Performance of Nickel Release Test Procedures: PD CR 12471:2002 and EN 1811:1998’. Two related presentations on computer modelling of investment casting were made by Jörg

Fig. 2 Cartier handbag test (Courtesy of A. Auberson)

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Fischer-Bühner (FEM, Germany): ‘Advances in the Prevention of Investment Casting Defects Assisted by Computer Simulation’ and Marco Actis Grande (Turin Polytechnic, Italy): ‘Computer Simulation of the Investment Casting Process: Widening of the Filling Step’. Their work concerned carat golds and they showed how gold alloys behave differently from silver (2). There is an urgent need to examine the behaviour of platinum and palladium alloys in these modelling experiments, as their material properties are very different from those of gold and silver.

Concluding Remarks The presentations relating to palladium as a jewellery alloy now provide a firm technical

underpinning of this exciting metal and its manufacture into jewellery. The technology of platinum jewellery manufacture was also addressed, adding to our already substantial knowledge base. From these and other standpoints, year 2007 proved to be yet another excellent vintage for the Santa Fe Symposium®. It is an unmissable event for all serious jewellery manufacturers. The Santa Fe Symposium® proceedings are published as a book and the PowerPoint® presentations are available on CD-ROM. They can be obtained from the organisers (1). The 22nd Symposium will be held once again in Albuquerque, New Mexico, from 18th to 21st May 2008.

References 1 2 3

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The Santa Fe Symposium: http://www.santafesymposium.org/ C. W. Corti, Platinum Metals Rev., 2007, 51, (1), 19 ‘Palladium – an introduction’, palladium jewellery technical manual, Johnson Matthey, New York, 2007: http://www.johnsonmattheyny.com/, in preparation ‘MJSA, World Gold Council Announce Creation of White Gold Whiteness Index’, Manufacturing Jewelers and Suppliers of America, press release, 15th March, 2005: http://www.mjsa.org/press/press_read.php?id=43

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6

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‘What is a White Gold?’, World Gold Council, March, 2005 and references therein: http://www.gold.org/jewellery/technology/ colours/white_guide.html J. Maerz, ‘Casting Gold to Platinum’, The 12th Santa Fe Symposium on Jewelry Manufacturing Technology, Albuquerque, New Mexico, 17–20 May, 1998, ed. D. Schneller, Met-Chem Research Inc, 1998, pp. 321–336 Official Journal of the European Union, Commission Directive 2004/96/EC, 27 September, 2004, EU, 28.9.2004, pp. L 301/51–L 302/52

The Reviewer Christopher Corti holds a Ph.D. in Metallurgy from the University of Surrey (U.K.) and is currently a consultant for the World Gold Council and the Worshipful Company of Goldsmiths in London. He served as Editor of Gold Technology magazine and currently edits Gold Bulletin journal and the Goldsmiths’ Company Technical Bulletin. A recipient of the Santa Fe Symposium® Research Award, Technology Award and Ambassador Award, he is a frequent presenter at the Symposium.


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DOI: 10.1595/147106707X238860

“Combinatorial and High-Throughput Discovery and Optimization of Catalysts and Materials” CRITICAL REVIEWS IN COMBINATORIAL CHEMISTRY, VOLUME 1 EDITED BY RADISLAV A. POTYRAILO (General Electric Global Research Center, New York, U.S.A.) AND WILHELM F. MAIER (Saarland University, Germany), CRC Press, Boca Raton, U.S.A., 2007, ISBN 978-0-8493-3669-0, £115.00, U.S.$199.95

A Selective Review by Kim Chandler* and Ann Keep** Johnson Matthey, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.; E-mail: *[email protected]; **[email protected]

and Sue Ellis† and Sarah Ball†† Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.; E-mail: †[email protected]; ††

[email protected]

Introduction

Gas-Sensitive Field-Effect Devices

This volume is the first in a series which covers molecular diversity and combinatorial chemistry, high-throughput discovery and associated technologies including characterisation techniques. Particular areas of interest having relevance to the platinum group metals (pgms) have been selected for a series of reviews in this Journal. The first of these appeared in the April 2007 issue (1). Here, Kim Chandler reviews Chapter 5: ‘A Combinatorial Method for Optimization of Materials for GasSensitive Field-Effect Devices’, by M. Eriksson, R. Klingvall and I. Lundström (Linköping University, Sweden). Sue Ellis reviews Chapter 7: ‘Infrared Thermography and High-Throughput Activity Techniques for Catalyst Evaluation for Hydrogen Generation from Methanol’, by Eduardo E. Wolf, Stephen Schuyten and Dong Jin Suh (University of Notre Dame, Indiana, U.S.A.). Ann Keep reviews Chapter 8: ‘New Catalysts for the Carbonylation of Phenol: Discovery Using High-Throughput Screening and Leads Scale-Up’, by Donald W. Whisenhunt and Grigorii Soloveichik (General Electric Global Research, U.S.A.); and Sarah Ball reviews Chapter 14: ‘High-Throughput Screening for Fuel Cell Technology’, by Jing Hua Liu, Min Ku Jeon, Asif Mahmood and Seong Ihl Woo (Korea Advanced Institute of Science and Technology, South Korea).

Gas-sensitive field-effect devices which incorporate a thin layer of a pgm such as palladium or platinum as gate material (the material used in the terminal gate area) have been developed for hydrogen and ammonia sensing. These devices, fabricated by semiconductor technology, have been employed in some specialised commercial applications. The team at Linköping University, Sweden, led by Professor Ingemar Lundström (one of the authors of the chapter), has dominated this field for more than thirty years, and is responsible for most of the impressive work done towards the understanding and advancement of these devices. Lundström’s team has shown that for catalytic metals such as palladium, platinum and iridium, both the type of metal and its morphology (porosity and thickness) play an important role in the sensitivity, stability and selectivity of the sensors. Chapter 5 begins with a general introduction and a brief history of gas sensors. Surprisingly, no mention is made of amperometric (toxic and oxygen) gas detectors which utilise pgm powders as electrodes and are commercially available and widely used. This is followed by a simple but useful illustration of the hydrogen sensing mechanism for a metal-insulator-semiconductor (MIS) device. The model, proposed by the authors several years ago, suggests that for a thick Pd film, three steps are


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involved: hydrogen dissociation on the gate metal surface, transportation of the hydrogen atom through the metal film, and trapping of the hydrogen atom at the metal insulator interface where polarisation occurs. Most of the complicated theory of MIS is omitted, so this chapter would most benefit readers who have field-effect transistor (FET) expertise. However, references for the underlying semiconductor principles – much of which were developed by the authors – are provided. The focus is on a combinatorial method for the optimisation of gas sensors, in line with the main theme of the book. Device performance can be improved by using two catalytic metal layers, each independently optimised. The first pgm metal layer is deposited at the metal-insulator interface and the second on top of the first. To achieve this using conventional FETs requires the preparation of large numbers of devices, while overcoming inconsistency between batches. The authors propose a neat and imaginative scheme that sidesteps these issues. By deploying a vacuum deposition process to vary the thickness of two metal layers independently, in orthogonal directions across a single substrate, all possible thickness combinations over a MIS capacitor device can be created. A scanning light pulse technique is employed which allows measurements of parameters analogous to FET characteristics at small illuminated points across the MIS substrate. This is used to study the gas response, so as to identify the best composition. The concept is clearly and effectively demonstrated on a rhodium (first film)/palladium bilayer with a thickness of up to around 25 nm. Results from exposure to hydrogen and ammonia (separately) are a series of very striking voltage response images. Areas exhibiting a high hydrogen sensitivity but a low ammonia sensitivity can be clearly identified. So can areas giving a high ammonia response but a low hydrogen response. Contour plots showing areas with different sensitivities resulting from exposure to different hydrogen concentrations are particularly vivid. The application of combinatorial methods in gas sensors is at an early stage of progress, so there is little literature for the authors to relate to. The pgms play a fundamental role in FET-based sensors. There


are also brief discussions on the effect of interference gases and accelerated ageing by heat treatment/annealing, but without inclusion of some of the pertinent values. The section on annealing might well have been expanded, as annealing appears to be capable of reversing the sensitivity. Since the device is operated at 140ºC, knowing the annealing temperature and duration would help to ascertain its stability. It is a little disappointing that there is no confirmatory study to show that the compositions identified by the experimental work really showed the sensitivities and selectivity described when applied to conventional FETs. Also most of the material was published in late 2005 (Reference 9 within the chapter, see (2)). Despite this, the chapter is authoritative and well prepared, albeit rather short – like most of the other chapters. The proposed combinatorial method is elegant and should promote further work. This chapter is essential reading for workers in this field and would also benefit scientists interested in material technology or highthroughput techniques.

Hydrogen Generation from Methanol In Chapter 7, the authors have used hydrogen generation from methanol as an example to highlight some of the benefits and weaknesses of applying a high-throughput approach to catalyst development. They discuss how high-throughput techniques complement standard catalyst screening methods, but acknowledge that they are no substitution for the detailed work required to gain a thorough understanding of the reaction and deactivation mechanisms. The authors start by reminding the readers that, historically, catalyst screening has followed an empirical approach. This still prevails to some extent, and they suggest that progress is normally limited by the amount of time available on test rigs. They propose that this ‘brute-force’ approach can be improved on by successfully combining high-throughput experimentation (HTE) with a knowledge-based catalyst design, based on a hypothetical reaction model. In the study presented, infrared thermography is used as an initial screening tool to assess the activity of a range of copper-zinc-palladium catalysts for the

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methanol partial oxidation reaction. This reaction has been studied in detail by many groups as a method for generating hydrogen to power fuel cells, although the fashion in the fuel cell industry currently favours the direct use of methanol or hydrogen fuel source. Nevertheless, the reaction is a useful illustrative example. While apparently simple, there are several side reactions that need to be taken account of in the interpretation of the HTE results. The milligram scale thermography tests are acknowledged as a crude first screen, offering no information on the kinetics, selectivity or durability of the catalysts. The authors rely on the exothermic nature of the chosen reaction, highlighting how the technique can only be applied to reactions where a measurable thermal response (due to reaction or adsorption) can be expected. The HTE tests are followed up by parallel reactor tests on 1 to 2 g of material before the most promising samples are studied in detail, with the kinetic and durability results feeding back to validate and improve the original reaction model. Unlike other applications where HTE is used, the performance of a heterogeneous catalyst is dependent on a range of subtle factors, over and above material composition, which affect the critical surface structure. One aspect that the authors do not highlight is that for heterogeneous catalysts, the synthesis of the materials is often the time consuming step that cannot be easily addressed by highthroughput techniques. In summary, the authors illustrate that while HTE should not be considered as the ‘Holy Grail’ of catalysis, if used wisely, it can be a valuable and powerful experimental tool.

Palladium-Catalysed Carbonylation of Phenol In Chapter 8, researchers from General Electric (GE) describe the use of high-throughput experiments to optimise the homogeneous palladiumcatalysed carbonylation of phenol. This work was carried out from 1997 onwards. The chapter gives both an overview of the reaction and detailed experimental procedures. Diphenylcarbonate is a raw material for the manufacture of polycarbonates such as Lexan®. It is


currently made in a two-step process: carbonylation of methanol to dimethylcarbonate followed by transesterification with phenol. A one-step process might have a lower environmental impact. However, so far, even the best processes for carbonylation of phenol to diphenylcarbonate suffer from low turnover numbers and poor rates. The best catalysts are palladium(II) complexes such as Pd(acac)2 (acac = acetylacetonato), Johnson Matthey’s product Pd-70, and Pd(dppb)Cl2 (dppb = 1,4-bis(diphenylphosphino)butane), Johnson Matthey’s product Pd-105. The GE researchers aimed to improve their activity with additives such as other metal complexes, bases, ligands and halides. For example, Ce(acac)3, PbO and tetraethylammonium bromide enhance activity. They used arrays of 2 cm3 gas chromatography (GC) vials inside an autoclave at 5 to 10 MPa and 100ºC. The results from these highthroughput experiments correlated well with performance when scaled up 200-fold. The results showed some complex synergistic effects when several metal additives were combined. For example, adding iron increases the turnover number of a system doped with lead and titanium from 1068 to 1631. These effects were surprising and would have been difficult to spot using traditional low-throughput methods. The performance of the Pd-70 catalyst improved from a turnover number around 500 to around 7000. GE ran some of the best catalytic systems in a one gallon benchtop continuous reactor and filed extensive patents on the process (3, 4). However, some comment on the likelihood of scaling up to a commercial process would have been welcome. Overall, the chapter gives a comprehensive account of the catalyst screening carried out. Clear graphs and tables detail the results, along with discussion of the possible reaction mechanism. It was pleasing to see high-throughput methods applied to a long-standing and intractable problem in homogeneous catalysis. The methods give unique insights into possible future ‘cocktail’ catalysts for industrial processes.

Fuel Cell Technology Chapter 14 reviews the different approaches that have been applied to date to high-throughput

206

screening of fuel cell electrocatalysts. Four different screening techniques are discussed: optical, electrochemical, scanning electrochemical and infra-red (IR) thermography. Examples are given for each technique, including types of catalyst array, methodologies for deposition of catalyst formulations, suitability of the techniques and their limitations. Optical screening using fluorescence is described as a coarser technique, useful for arrays with wide compositional variations, but with some limitations in sensitivity. Electrochemical and scanning electrochemical microscopy techniques allow greater accuracy and flexibility, with possibilities to vary the electrolyte, solution and reactants, as well as the catalyst formulations studied. The examples used within the chapter cover the electrochemical reactions of oxygen reduction and evolution, methanol oxidation and hydrogen oxidation in the presence of carbon monoxide (CO) impurities. The techniques described can be used to give information on reaction pathways and the effects of catalyst particle size on catalytic activity, as well as the variation in activity with catalyst formulation. IR thermography screening is also described, as a method to determine the gas phase activity of transition and base metal oxide-doped platinum on carbon catalysts for removal of impurities such as CO under fuel cell operating conditions. The review would be useful for those requiring an introduction to the variety of rapid screening techniques available for fuel cell catalysts. References are made to a range of relevant literature papers covering different types of catalyst array, data analysis techniques, and findings regarding improved catalyst formulations for methanol oxidation and oxygen reduction and evolution. A familiarity with the fuel cell reactions within proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) is assumed. Figures within the chapter are well chosen to illustrate the principles behind the different types of screening techniques and methods of plotting activity data for complex ternary, quaternary and even quinternary catalyst compositions. All examples discussed relate to pgm-containing catalysts, in particular platinum and ruthenium, reflecting the current requirement for these metals within PEMFC and DMFC catalysts. However,


combinatorial techniques are described as offering a clear opportunity to rapidly screen a wide range of catalyst formulations containing pgm and non-pgm elements, with a view to reducing catalyst costs without compromising activity. Generally the catalyst materials described have been prepared by techniques such as thin film sputtering and dispensing of metal solutions to produce microdots, followed by a reduction or heat treatment step. These methods use small amounts of materials and allow a wide compositional range to be studied rapidly. Little comment is made on attempts to reproduce the most active catalyst formulations at a larger scale, and to verify the predictions made by rapid screening in operational fuel cell systems. As rapid screening techniques have only recently been applied in the area of fuel cell catalysis, the preparation and validation of active formulations from combinatorial studies at larger scales will still be in progress at this time.

Concluding Remarks The chapters reviewed in Platinum Metals Review here and in a previous issue (1) cover some of the range of industrial applications of relevance to the pgms which have been studied using combinatorial and high-throughput techniques. These include data storage materials and technology (1), gas-sensitive field-effect devices, catalyst development for hydrogen generation and for the carbonylation of phenol, and fuel cell electrocatalyst technology. A further review of the entire book: “Combinatorial and High-Throughput Discovery and Optimization of Catalysts and Materials” can be read in Reference (5).

References 1 2 3 4 5

D. M. Newman and M. L. Wears, Platinum Metals Rev., 2007, 51, (2), 93 R. Klingvall, I. Lundström, M. Löfdahl and M. Eriksson, IEEE Sens. J., 2005, 5, (5), 995 K. V. Shalyaev, G. L. Soloveichik, D. W. Whisenhunt Jr. and B. F. Johnson, General Electric, U.S. Patent 6,440,892; 2002 K. V. Shalyaev, B. F. Johnson, D. W. Whisenhunt Jr. and G. L. Soloveichik, General Electric, U.S. Patent 6,440,893; 2002 O. Trapp, Angew. Chem. Int. Ed., 2007, 46, (12), 1943

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ABSTRACTS

of current literature on the platinum metals and their alloys PROPERTIES

CHEMICAL COMPOUNDS

Platinum-Catalyzed High Temperature Oxidation of Metals

Self-Assembly of a Nanoscopic Platinum(II) Double Square Cage

Q. DONG, G. HULTQUIST, G. I. SPROULE and M. J. GRAHAM,

S. GHOSH, S. R. BATTEN, D. R. TURNER and P. S. MUKHERJEE,

Corros. Sci., 2007, 49, (8), 3348–3360

Organometallics, 2007, 26, (13), 3252–3255

Al, Cr, Ni and Zr were sputter-coated with porous Pt films (1). SIMS analysis on partly Pt-coated metal samples at different oxide depths in areas with Pt and in areas away from Pt indicated an enhanced inward oxide growth in the Pt area and at mm-ranged distance from the Pt area. Weight gain measurements on Pt-coated Ni samples showed a reduced or increased oxidation rate depending on the amount of (1).

A rigid tripodal ligand (1) with an ester cap (1 = 1,1,1-tris(4-pyridyl)COOR, where R = PhCH(C2H5)) was designed and prepared. A 2:3 self-assembly of (1) with cis-(PEt3)2Pt(OTf)2 as a 90º ditopic acceptor unit yielded an unusual 3D cage (2). Multinuclear NMR spectroscopy and single-crystal structure analysis were used to characterise (2).

SERS at Structured Palladium and Platinum Surfaces M. E. ABDELSALAM, S. MAHAJAN, P. N. BARTLETT, J. J. BAUMBERG and A. E. RUSSELL, J. Am. Chem. Soc., 2007, 129,

(23), 7399–7406

Templated electrodeposition through colloidal templates was used to produce thin (< 1 μm) films (1) of Pt- and Pd-containing close packed hexagonal arrays of uniform sphere segment voids. The SERS spectra for benzenethiol adsorbed on the surfaces of (1) with different thicknesses and void diameters are reported. For 633 nm radiation, enhancement factors of 550 and 1800 can be obtained for Pt and Pd, respectively. Martensitic Transformation in TiPd Shape Memory Alloys Studied by PAC Method with 181Ta Probes A. KULINSKA and P. WODNIECKI, Intermetallics, 2007, 15, (9),

1190–1196

The perturbed angular correlation method was applied to study the martensitic phase transition of the title alloy doped with 181Hf/181Ta probe atoms. Strong dependences of the martensite start temperature (MS) and the shape of the hysteresis loop (TH) on the small admixture of the Hf impurities in TiPd compound were found. The observed decrease of the MS value differs from the behaviour of TiNi, where adding Hf as the third element leads to a rise of MS. Deformation Tracks Distribution in Iridium Single Crystals Under Tension P. PANFILOV,

J. Mater. Sci., 2007, 42, (19), 8230–8235

The deformation tracks distribution in a single crystal of f.c.c.-Ir (1), which exhibits cleavage after considerable elongation, is considered. Octahedral slip is the sole deformation mechanism in (1) at room temperature. In contrast to other f.c.c.-metals, the resource of plasticity of (1) is exhausted at the initial/early stages of plastic deformation, when the octahedral slip bands are homogeneously distributed on the working surface and necking is absent in the vicinity of the dangerous crack.


Nickel(II), Palladium(II) and Platinum(II) Complexes of N-Allyl-N'-pyrimidin-2-ylthiourea S. S. KANDIL, S. M. A. KATIB and N. H. M. YARKANDI, Transition

Met. Chem., 2007, 32, (6), 791–798

The title complexes with N-allyl-N'-pyrimidin-2-ylthiourea (1) were synthesised in 1:1 and 1:2 [metal:ligand] stoichiometric ratios. The 1H- and 13C- NMR chemical shifts revealed coordination of one pyrimidine-N and S atoms to Pt(II) and Pd(II). The IR spectra indicated (1) acts as a bidendate ligand towards Pt(II) and Pd(II), and coordinates via thione-S and a pyrimidine-N. Synthesis and X-ray Structures of Water-Soluble Tris(hydroxymethyl)phosphine Complexes of Rhodium(I) F. LORENZINI, B. O. PATRICK and B. R. JAMES,

Dalton Trans.,

2007, (30), 3224-3226

H2O-soluble Rh(I) complexes: RhCl(1,5-cod)(THP) (1), [Rh(1,5-cod)(THP)2]Cl (2), RhCl(THP)4 (3), and trans-RhCl(CO)(THP)2 (4) (THP = P(CH2OH)3) have been synthesised and characterised. (1), (2) and (3) are reported to be the first potentially useful entries into Rh(I)-THP chemistry, while (1) and (4) are the first structurally characterised Rh(I)-THP complexes.

PHOTOCONVERSION Highly Phosphorescent Perfect Green Emitting Iridium(III) Complex for Application in OLEDs H. J. BOLINK, E. CORONADO, S. GARCIA SANTAMARIA, M. SESSOLO, N. EVANS, C. KLEIN, E. BARANOFF, K. KALYANASUNDARAM, M. GRAETZEL and MD. K. NAZEERUDDIN, Chem. Commun.,

2007, (31), 3276–3278

Bis-(2-phenylpyridine)(2-carboxy-4-dimethylaminopyridine)iridium(III) (N984) was synthesised by reacting [Ir(ppy)2(Cl)]2 with methyl-dimethylaminopicolinate and Na2CO3 in 2-ethoxyethanol. A solution processable OLED device incorporating the yellow N984 complex displays electroluminescence spectra with a narrow bandwidth of 70 nm at half of its intensity, with colour coordinates that are very close to the PAL standard for a green emitter.

208

Periodic Mesoporous Silica having Covalently Attached Tris(bipyridine)ruthenium Complex: Synthesis, Photovoltaic and Electrochemiluminescent Properties

Preparation and Characterisation of PalladiumLoaded Polypropylene Porous Hollow Fibre Membranes for Hydrogenation of Dissolved Oxygen in Water

J. FONT, P. DE MARCH, F. BUSQUÉ, E. CASAS, M. BENITEZ, L. TERUEL and H. GARCÍA, J. Mater. Chem., 2007, 17, (22),

R. VAN DER VAART, V. I. LEBEDEVA, I. V. PETROVA, L. M. PLYASOVA, N. A. RUDINA, D. I. KOCHUBEY, G. F. TERESHCHENKO, V. V. VOLKOV and J. VAN ERKEL, J. Membrane Sci., 2007, 299,

2336–2343

A tris(bpy)Ru derivative with two terminal triethoxysilyl groups attached to one of the bpy ligands was used with TEOS for the preparation of a tris(bpy)Ru-containing mesoporous silica (1), using CTABr as a structure-directing agent. The tris(bpy)Ru at the walls in (1) gives its orange coloration. (1) exhibits photovoltaic (VOC = 140 mV, ISC = 2.6 μA) and electrochemiluminescence activity (λmax = 610 nm).

SURFACE COATINGS Plasma-Enhanced Atomic Layer Deposition of Palladium on a Polymer Substrate G. A. TEN EYCK, S. PIMANPANG, J. S. JUNEJA, H. BAKHRU, T.M. LU and G.-C. WANG, Chem. Vap. Deposition, 2007, 13, (6–7),

307–311

Pd has been deposited on air-exposed, annealed poly(p-xylylene) (PPX) at 80ºC using a remote, inductively coupled, H2/N2 plasma with Pd(hfac)2 as the precursor. By optimising the mixture of H2 and N2, the PPX surface is modified to introduce active sites allowing the chemisorption of the Pd(hfac)2. In addition, enough free H atoms are available at the surface for ligand removal and Pd reduction, while at the same time, enough H atoms are consumed in the plasma to ensure there is no degradation of the PPX.

APPARATUS AND TECHNIQUE Classification of Multiple Defect Concentrations in White Wine by Platinum Microelectrode Voltammetry L. FRANCIOSO, R. BJORKLUND, T. KRANTZ-RÜLCKER and P. SICILIANO, Sens. Actuators B: Chem., 2007, 125, (2), 462–467

(1–2), 38–44

Pd could be deposited on a hydrophobic porous Accurel polypropylene membrane hollow fibre, while keeping its hydrophobic nature. Pd loadings as low as 0.36% (w/w) were sufficient to catalyse the hydrogenation of dissolved O2 while maintaining diffusion limited kinetics. A fast O2 removal system was obtained that has the potential of maintaining removal rate, even at very low concentrations of O2.

HETEROGENEOUS CATALYSIS Effect of Palladium on Sulfur Resistance in Pt–Pd Bimetallic Catalysts H. JIANG, H. YANG, R. HAWKINS and Z. RING,

Catal. Today,

2007, 125, (3–4), 282–290

The interactions of H2 and H2S with Pt-Pd bimetallic catalysts (1) were studied using DFT. When alloying the Pt catalyst with a small amount of Pd at a particular surface atomic ratio range, the adsorptions of both H2 and H2S were enhanced, but the adsorption energy of H2 increased more than that of H2S. The desorption energy of H2 from Pt or Pd, as well as of (1) supported on a zeolite, were calculated by TPD; these values were compared against the DFT results to explain why (1) has better S resistance than Pt. The Effect of Ionic Liquid in Supported Ionic Liquid Catalysts (SILCA) in the Hydrogenation of α,β-Unsaturated Aldehydes P. VIRTANEN, H. KARHU, K. KORDAS and J.-P. MIKKOLA, Chem.

Eng. Sci., 2007, 62, (14), 3660–3671

Concentrations of defect pairs added to a white wine were classified by voltammetric measurements on interdigitated Pt microelectrodes using principal component analysis of the current responses. Ascorbic acid/acetaldehyde, ascorbic acid/SO2 and acetaldehyde/SO2 combinations of 0, 1, 2 and 3 mM concentrations were investigated.

Pd nanoparticles/ionic liquid layer/active C cloth SILCAs (1) were successfully employed in two different hydrogenation processes. Leaching of both Pd and ionic liquids was found to be negligible, and not the reason for slow deactivation of (1). The ionic liquid layer residing on the support of (1) can either enhance the reaction rate or affect the selectivity profile of the reaction.

Amperometric Glucose Biosensor Based on Electrodeposition of Platinum Nanoparticles onto Covalently Immobilized Carbon Nanotube Electrode

Palladium Ethylthioglycolate Modified Silica–A New Heterogeneous Catalyst for Suzuki and Heck Cross-Coupling Reactions

Talanta, 2007, 71, (5),

2040–2047

M. AL-HASHIMI, A. C. SULLIVAN and J. R. H. WILSON, J. Mol. Catal. A: Chem., 2007, 273, (1–2), 298–302

A fabricated GOx/Aunano/Ptnano/CNT electrode (1) was covered with a thin layer of Nafion to avoid the loss of GOx (glucose oxidase) and to improve the anti-interferent ability. (1) exhibited rapid response for glucose in the absence of a mediator. The biosensor based on (1) had good reproducibility and stability for the determination of glucose.

A silica-supported S-containing ethylthioglycolate material that readily binds Pd from solutions of Pd(OAc)2 was synthesised. This affords an active and recyclable solid phase catalyst (1). Close to quantitative conversions were observed with (1) for Suzuki reactions in less than 2 h. The Heck reactions were complete within 24 h.

X. CHU, D. DUAN, G. SHEN and R. YU,


209

Effect of Liquid Property on Adsorption and Catalytic Reduction of Nitrate over HydrotalciteSupported Pd-Cu Catalyst Y. WANG, J. QU and H. LIU, J. Mol. Catal. A: Chem., 2007, 272,

(1–2), 31–37

Nitrate ions were adsorbed by Pd-Cu/hydrotalcite (1) at 10, 25 and 35ºC. Higher reaction temperature accelerated nitrate adsorption and reduction, and simultaneously decreased the accumulation of NO2– and NH4+. pH and coexisted ions in the H2O also showed influence on nitrate removal. The activity of (1) was maintained after repeated use. Combining Diffuse Reflectance Infrared Spectroscopy (DRIFTS), Dispersive EXAFS, and Mass Spectrometry with High Time Resolution: Potential, Limitations, and Application to the Study of NO Interaction with Supported Rh Catalysts M. A. NEWTON, A. J. DENT, S. G. FIDDY, B. JYOTI and J. EVANS,

Catal. Today, 2007, 126, (1–2), 64–72

The title experiment was used to study the oxidation (by NO) and reduction (by H2) of Rh/γ-Al2O3. The specific role that the linear NO+ species has in both oxidation and reduction of Rh, and the role it may play reactively at elevated temperatures were determined. New information was gained about the physical character of the linear NO+ species and the nature of the Rh phase/sites with which it is associated.

X. JIANG, J. SCLAFANI, K. PRASAD, O. REPIC BLACKLOCK, Org. Process Res. Dev., 2007, 11, (4),

and T. J. 769–772

Pd was loaded onto Smopex-111 by stirring a prefiltered toluene solution of Pd(OAc)2 and Smopex-111 heated to 70ºC. After filtration and washing, the complex was dried to give Pd-Smopex-111 (1) with a Pd loading of 4.4–4.7 wt.%. (1) was a highly active catalyst for Heck and Suzuki cross-coupling reactions. Both electron-donating and electron-withdrawing groups on the aryl bromide were tolerated. (1) is recyclable with no noticeable change in activity. Isolation of (1) involves simple filtration. A Convenient Catalyst System for Microwave Accelerated Cross-Coupling of a Range of Aryl Boronic Acids with Aryl Chlorides M. L. CLARKE, M. B. FRANCE, J. A. FUENTES, E. J. MILTON and G. J ROFF, Beilstein J. Org. Chem., 2007, 3, 18

A readily prepared, air-stable Pd precatalyst derived from the amine-phosphine ligand, dcpmp, promoted Suzuki cross-coupling between activated aryl chlorides and a range of boronic acids under microwave heating conditions. High yields of the product biaryls were obtained in 15 min or less. Heavily fluorinated boronic acids do not participate in these Suzuki couplings due to protodeboronation. Catalytic Hydrogenation of Nitrile Rubber Using Palladium and Ruthenium Complexes

HOMOGENEOUS CATALYSIS Phosphine Oxides as Stabilizing Ligands for the Palladium-Catalyzed Cross-Coupling of Potassium Aryldimethylsilanolates S. E. DENMARK, R. C. SMITH and S. A. TYMONKO,

Pd–Smopex-111: A New Catalyst for Heck and Suzuki Cross-Coupling Reactions

Tetrahedron,

2007, 63, (26), 5730–5738

The Pd-catalysed cross-coupling reaction of potassium (4-methoxyphenyl)dimethylsilanolate with aryl bromides has been achieved using Ph3P(O) as a stabilising ligand. Allylpalladium(II) chloride dimer was employed as a precatalyst. Unsymmetrical biaryls were prepared from a variety of aryl bromides in good yield with short reaction times.

G. A. S. SCHULZ, E. COMIN and R. F. DE SOUZA, J. Appl. Polym.

Sci., 2007, 106, (1), 659–663

The hydrogenation of acrylonitrile-butadiene copolymer (NBR) using Pd(OAc)2 or RuCl2(PPh3)3 catalysts has been investigated in order to produce a totally saturated nitrile rubber. The hydrogenation of NBR is effective with both catalysts and under the appropriate conditions total conversion to HNBR is achievable. Pd(OAc)2 requires harsher reaction conditions and has the drawback of gel formation under high conversion. The degree of hydrogenation was determined by IR and NMR spectroscopy.

R. ANDRÉS, E. DE JESÚS and J. C. FLORES, New J. Chem., 2007,

Hydroformylation of Higher Olefin in HalogenFree Ionic Liquids Catalyzed by Water-Soluble Rhodium–Phosphine Complexes

31, (7), 1161–1191

Q. LIN, W. JIANG, H. FU, H. CHEN and X. LI,

The advances in Pd-catalysed reactions using dendrimer-based catalysts are reviewed. This includes the role of Pd dendrimers as: (a) soluble macromolecules for the support of catalysts, that are separable by nanofiltration techniques; (b) ligand-modifiers that can tune the solubility of the catalyst; (c) spacers for catalyst immobilisation on silica or polymers; and (d) precursors for the synthesis of mono- and bimetallic nanoparticles of controlled size and narrow size distribution. Examples of catalysis with related metal systems, such as star-shaped molecules or hyperbranched polymers, are also included. (169 Refs.)

Gen., 2007, 328, (1), 83–87

Catalysts Based on Palladium Dendrimers


Appl. Catal. A:

The biphasic hydroformylation of higher olefins was carried out in 1-n-alkyl-3-methylimidazolium ptoluenesulfonate using Rh-TPPTS complexes as the catalyst. High activity and chemoselectivity for aldehyde with retention of the catalyst in the ionic liquid phase was exhibited. The ionic liquid containing catalyst can be easily separated and reused. The reaction rate is dependent on the cation and anion of the ionic liquids used. Furthermore, the reaction rate was accelerated when the chain length of the alkyl in the ionic liquids was comparable with that of the olefin.

210

FUEL CELLS

MEDICAL USES

Combinatorial Electrochemical Cell Array for High Throughput Screening of Micro-Fuel-Cells and Metal/Air Batteries

Two Different Types of Age-Hardening Behaviors in Commercial Dental Gold Alloys

R. JIANG,

Rev. Sci. Instrum., 2007, 78, (7), 072209

K. HISATSUNE, T. SHIRAISHI, Y. TAKUMA, Y. TANAKA and R. H. LUCIANO, J. Mater. Sci.: Mater. Med., 2007, 18, (4), 577–581

An electrochemical cell array (1) was designed that contains a common air electrode and 16 microanodes for high-throughput screening of both fuel cells (based on PEM) and metal/air batteries. Electrode materials were coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. (1) was used to study DMFCs, including high-throughput screening of electrode catalysts involving Pt and Ru, and determination of optimum operating conditions.

Age-hardening behaviour during continuous heating in the title alloys was studied by means of electrical resistivity measurements, hardness tests and XRD. Two distinguishable behaviours were found. The difference was attributed to the amount of Pt, and the atomic ratio of Au and Cu in each alloy. The phase transformations during continuous heating progressed in two stages. Increase of the Pt addition in the alloys retards the rate of the reaction and decreases the amount of the first stage.

Catalysts for Direct Ethanol Fuel Cells

Hardening and Overaging Mechanism of a Commercial Au–Ag–Cu–Pd Dental Alloy

E. ANTOLINI,

J. Power Sources, 2007, 170, (1), 1–12

The electrocatalysts which have been tested as anode and cathode materials for DEFCs are reviewed, with attention focused on the catalyst composition, degree of alloying, presence of oxides and activity for the EtOH oxidation reaction. Conversely to the MeOH oxidation reaction, the best binary catalyst for EtOH oxidation in acid environment is not Pt-Ru but Pt-Sn. Ternary Pt-Ru- and Pt-Sn-based electrocatalysts are also described. Pt-Pd (9:1) showed higher EtOH tolerance than Pt when used as cathode material. (90 Refs.) Carbon Nanotubes Supported Pt-Ru-Ni as Methanol Electro-Oxidation Catalyst for Direct Methanol Fuel Cells F. YE, S. CHEN, X. DONG and W. LIN, J. Nat. Gas Chem., 2007,

16, (2), 162–166

Pt-Ru/CNTs and Pt-Ru-Ni/CNTs catalysts were prepared by reduction of metal precursors with NaBH4 at room temperature. The particle size of the Pt-Ru-Ni/CNTs catalyst is ~ 4.8 nm. The catalytic activity and stability for MeOH electrooxidation were measured by electrochemical impedance spectroscopy, linear sweep voltammetries, and chronoamperometry. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of the Pt-Ru/CNTs catalyst. Pt and Ni Carbon Nitride Electrocatalysts for the Oxygen Reduction Reaction V. DI NOTO, E. NEGRO, R. GLIUBIZZI, S. GROSS, C. MACCATO and G. PACE, J. Electrochem. Soc., 2007, 154, (8), B745–B756

A precursor (1) was prepared from a Pt chloride and a Ni cyanometallate complex in the presence of sucrose, which acts as an organic binder. The thermal decomposition of (1), which was studied at 400–700°C, and the procedure for activating the products, were critical. The electrochemical efficiency in the O reduction reaction of the title electrocatalysts proved to be much higher than that of standard materials having a similar Pt content.


H.-I. KIM, G.-H. JEON, S.-J. YI, Y. H. KWON and H.-J. SEOL, J. Alloys

Compd., 2007, 441, (1–2), 124–130

The ageing behaviour and age-hardening of the title alloy (1) with small amounts of Pt, Zn and Ir (48.0 wt.% Au-32.5 wt.% Ag-8.0 wt.% Cu-7.4 wt.% Pd-2.0 wt.% Pt-2.0 wt.% Zn-0.1 wt.% Ir) was investigated. (1) showed apparent age-hardenability at the ageing temperature of 400ºC. By ageing, the hardness of the solution-treated specimen began to increase and reached a maximum value, and then the hardness decreased continuously by further ageing. Guanine Binding to Dirhodium Tetracarboxylate Anticancer Complexes: Quantum Chemical Calculations Unravel an Elusive Mechanism D. V. DEUBEL and H. T. CHIFOTIDES, Chem. Commun., 2007, (33), 3438–3440

The mechanism of guanine binding to dirhodium tetracarboxylates, representing an emerging class of metal–metal-bonded antitumour complexes, has been established. Numerous experiments led to the characterisation of the reactants and products, but the reaction mechanism had not been established. Highlevel quantum chemical calculations suggest a multiple-step mechanism via an axial Gua-N7 adduct and an ax–eq carboxylate chelate as unexpected key intermediates. Synthesis, Characterization and Antimalarial Activity of New Iridium–Chloroquine Complexes M. NAVARRO, S. PEKERAR and H. A. PÉREZ,

Polyhedron, 2007,

26, (12), 2420–2424

Chloroquine base (CQ) reacted with [Ir(COD)Cl]2 and IrCl3·3H2O to give Ir(CQ)Cl(COD) (1) and Ir2Cl6(CQ)·3H2O (2), respectively. Reaction of [Ir(COD)Cl]2 with CQ in the presence of NH4PF6 gave [Ir(CQ)(Solv)2]PF6 (3). Complexes (1)–(3) were evaluated in vitro against Plasmodium beghei. Comparison of the IC50 values obtained with complexes (1)–(3) with that for chloroquine diphosphate indicated a higher activity for (2), while (1) and (3) showed a similar and lower activity, respectively.

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NEW PATENTS ELECTRODEPOSITION AND SURFACE COATINGS Palladium Activator for Plating on Plastic HANGZHOU ORIENTAL MET. FINISHING TECHNOL. CO LTD

Chinese Appl. 1,936,097

Plastic can be activated for plating using an activator containing (in g l–1): 0.05–10 Cu(I) salt; 0.05–2 Pd(II) compound; 2.5–200 Sn; plus 35% HCl 50–800 ml l–1. The steps followed are: deoiling, cleaning, roughening, cleaning, activating at 10–70ºC for 0.5–10 min, cleaning, treating with a basic solution containing Cu ions, then plating. The process is claimed to be simple, stable and environmentally friendly. The activator is claimed to have high activity.

APPARATUS AND TECHNIQUE Ignition Device with Iridium-Based Firing Tip FEDERAL MOGUL IGNITION UK LTD

European Appl. 1,782,513

An ignition device such as a spark plug for an internal combustion engine includes centre and ground electrodes, at least one of which includes a firing tip formed from an Ir alloy. The alloy contains (in wt.%): 1–3 Rh, 0.1–0.5 W, 0.01–0.05 Zr, preferably ~ 2 Rh, ~ 0.3 W, ~ 0.02 Zr, with the balance Ir. The ground electrode firing tip may alternatively be made from Pt or a Pt alloy. Microchannel Apparatus with Platinum Aluminide VELOCRYS INC

World Appl. 2007/047,373

A microchannel reactor or separator contains at least one microchannel defined by a wall coated with PtAl, with optionally a layer of Al2O3 and one of catalytic or sorbent material. The PtAl layer may be a post-assembly coating, and the reactor or separator made by laminating together sheets. Pt may be coated by electroless plating. A reaction may be carried out by passing a reactant into the microchannel to form at least one product; if the reactant is a hydrocarbon then the reactor can be used to effect hydrocarbon steam reforming. Essentially no coke is formed in the microchannel. Adsorption of VOCs Including Ethylene JOHNSON MATTHEY PLC

World Appl. 2007/052,074

Pd-doped ZSM-5 (1) is used to adsorb volatile organic compounds such as C2H4, HCHO or CH3CO2H from perishable organic matter which may include foods such as fruit or vegetables, horticultural produce such as cut flowers or plants, or refuse. (1) may be incorporated into a storage container, package or label and may be used with a VOC indicator. The used (1) can be regenerated for further use by heating to 250ºC for 30 min in air to release the adsorbed VOCs. Ratio of Si:Al in the ZSM-5 is ≤ 100:1, preferably 22:1–28:1; and Pd content is 0.1–10.0 wt.%, preferably 0.5–5.0 wt.%.


Osmium-Based Oxygen Sensor W. B. CARLSON et

al.

U.S. Appl. 2007/0,105,235

A luminescent Os complex [Os(II)(N–N)2L-L]2+ 2A– or A2– (1), where N–N is a 1,10-phenanthroline ligand; L-L is cis-1,2-bis(diphenylarseno)ethylene or cis-1,2-bis(diphenylphosphino)ethylene; and A is a counter ion; plus an O2 permeable host material, is used in a pressure sensitive paint. The pressure of an O2-containing fluid flowing over an aerodynamic surface, such as an aircraft part, can be measured by illuminating the coated surface to cause luminescence of (1), then measuring the luminescent intensity. Ruthenium-Containing Biosensor NATL. YUNLIN UNIV. SCI.

U.S. Appl. 2007/0,095,664

A biosensor includes an extended gate field-effect transistor structure which has a metal oxide semiconductor field-effect transistor and at least one sensing unit, with a Ru-containing layer as a sensor, connected by a metal wire. The Ru-containing film is chosen from Ru oxide or RuN and is coated onto the extended gate region substrate by radio frequency sputtering. The sensor system can be used for measuring pH of solutions or in a vitamin C biosensor. Platinum-Gold Gas Sensor Electrodes DELPHI TECHNOL. INC

U.S. Patent 7,241,477

A method for forming a PtAu alloy electrode for use in a gas sensor includes combining Pt and Au precursors to form an electrode ink, forming the ink into an electrode precursor, firing and treating in an environment of ≤ 500 ppm O2 to produce an electrode with an exposed surface Au concentration ≥ 6 times the bulk Au concentration. The electrode ink contains (in wt.%): 43–62 Pt, 0.05–1 Au and 38–48 fugitive material, plus optionally 2–8 oxides.

HETEROGENEOUS CATALYSIS Iridium Catalyst for Methane-Containing Waste Gas OSAKA GAS CO LTD European Appl. 1,790,412 A catalyst for removing hydrocarbons from combustion exhaust gas containing CH4 and excess O2 contains Ir plus Pt, Pd, Rh and/or Ru, supported on ZrO2, and has specific surface area 2–60 m2 g–1. Ir is present in 0.5–20 wt.%, preferably 1–5 wt.%, relative to ZrO2. Where Pt is used, it is present in 2–100 wt.%, preferably 5–50 wt.%, relative to Ir. Alternatively or in addition to Pt, elements Pd, Rh and/or Ru may be present in 0.5–10 wt.%, preferably 1–5 wt.%, relative to Ir. Zoned Oxidation Catalyst for Exhaust System JOHNSON MATTHEY PLC

World Appl. 2007/077,462

An exhaust system for a lean-burn internal combustion engine includes a catalyst for oxidising CO and hydrocarbons. A flow-through substrate monolith supports three washcoat zones each containing at least one metal selected from Pt, Pd, Rh and Ir, preferably Pt. Metal loadings in each washcoat zone are (in g ft–3): 10–240 in the first, 5–30 in the second and 10–120 in the third; 25–390 total metal loading.

212

Dry Impregnation of Platinum on Carbon Substrate U.S. Appl. 2007/0,105,007

UNIV. ILLINOIS

A method of preparation for particles of a metal selected from Pt, Pd, Rh, Ru, Ir, Os, Sn or Cu, preferably Pt, supported on a C substrate such as C black is claimed. An aqueous solution of metal complex in a volume of H2O not exceeding the pore volume of the C substrate is contacted with the substrate, allowed to absorb, then heated under reducing conditions to form particles. The pH of the solution is adjusted if necessary to < 2 and the Pt-loaded substrate is heated to 200–300ºC. Particles have diameter 15–25 Å and Pt is highly dispersed, at least 120 m2 Pt g–1 Pt, with Pt loadings ≥ 20%. Carbon Monoxide Catalyst A. CHIGAPOV et

al. (FORD GLOBAL TECHNOL. LLC) U.S. Appl. 2007/0,129,247

A low-temperature selective CO oxidation catalyst contains 1–20 wt.% Pt and 1–30 wt.% Co, and has > 90% conversion efficiency at ≤ 140ºC. Alternatively the catalyst may contain 1–10 wt.% Pt and 1–4 wt.% Co and have conversion efficiency > 50% at 22–33ºC. The weight ratio of Pt:Co is between 1:2–4:1. Applications may include removal of CO from H2-rich gas for fuel cells, from exhaust gas during cold-start of diesel or petrol engines, or for air purification systems for spaces such as tunnels, underground railways, multi-storey carparks or submarines. Iridium Catalyst for Hydrazine Decomposition KOREA AEROSPACE RES. INST.

U.S. Appl. 2007/0,167,322

An Ir catalyst is claimed which has high crush strength and can be used for hydrazine decomposition for spacecraft and satellite propulsion. Bauxite is contacted with 0.1–10 M acid solution for 10–14 h; the mixture is filtered; the filtered bauxite is thermally treated by contacting with air at 500–700ºC for 2–6 h, then loaded with Ir from a solution containing IrCl3, Ir[(NH3)5Cl]Cl2, H2IrCl6 or Ir(NH3)6Cl3. The loading step may be repeated 10–20 times to give an Ir loading of 30–35 wt.% relative to bauxite. In a final step, the catalyst is reduced. Exhaust Gas Purifying Catalyst U.S. Patent 7,235,511

MAZDA MOTOR CORP

A catalyst includes a carrier and a catalyst layer which includes a noble metal on active Al2O3, Rh carried on an O storage agent, Rh carried on Al2O3 coated with ZrO2 and a binder material. The O storage agent may be a CeO2-ZrO2-Nd2O3 composite.

HOMOGENEOUS CATALYSIS Synthesis of Aryloctanoyl Amide Compounds British Appl. 2,431,652

NOVARTIS AG

An alternative synthesis of (2S, 4S, 5S, 7S)-2,7-dialkyl4-hydroxy-5-amino-8-aryloctanoyl amide derivatives or pharmaceutically acceptable salts thereof, in particular aliskiren, uses a Pd-catalysed coupling reaction. Novel compounds used as intermediates in the synthesis of the target compounds are also claimed. Ruthenium Metathesis Catalysts MATERIA INC

World Appl. 2007/075,427

Ruthenium alkylidene complexes having an Nheterocyclic carbene ligand with a 5-membered heterocyclic ring containing at least one phenylsubstituted N atom bonded directly to a carbenic C atom are claimed. The complexes can be used as catalysts for olefin metathesis reactions, in particular for preparation of tetra-substituted cyclic olefins by ring closing metathesis. Hydrogenation Process DAVY PROCESS TECHNOL. LTD

U.S. Appl. 2007/0,142,679

A continuous homogeneous process for hydrogenation of dicarboxylic acids and/or anhydrides uses a catalyst containing Ru, Rh, Os, Pd or Fe, preferably Ru, with an organic phosphine, preferably a tridentate phosphine. Products may include butanediol, THF and/or γ-butyrolactone from fumaric acid or maleic or succinic acid or anhydride. The process is carried out in the presence of ≥ 1 wt.% H2O, at 500–2000 psig and 200–300ºC, so that ~ 1–10 mol H2(g) are used to strip 1 mol product from the reactor. The catalyst can be regenerated in the presence of H2O and H2(g).

FUEL CELLS Ruthenium-Selenium Alloy Cathode Catalyst SAMSUNG SDI CO LTD


A cathode catalyst for a fuel cell includes a Ru-Se alloy with average particle size ≤ 6 nm, preferably 3–5 nm, preferably as an amorphous catalyst. The composition contains 3–20 wt.% Se vs. Ru, and Ru makes up 10–90 wt.% of the total catalyst composition. The catalyst is prepared by drying a solution containing RuCl3 hydrate, Ru acetylacetonate, Ru carbonyl or a mixture, heat treating the product, then adding a solution containing selenous acid and heat treating a second time. Platinum-Gold Alloy Catalyst

Shift Reaction Catalyst NISSAN MOTOR CO LTD

JOHNSON MATTHEY PLC

Japanese Appl. 2007-007,531

A water gas shift reaction catalyst includes Pt, Ce and Cu and is prepared by mixing a Pt catalyst powder containing Ce, with a Cu catalyst powder. The composition may further include Ti, Zr, V, Nb or Ta. The components are present in (mg ml–1 by catalyst unit volume): 0.1–20 Pt, 50–500 Ce and 0.1–80 Cu. Cu is 0.1–10 mass% vs. Pt. The support is an inorganic oxide of Si, Al, Ti, Ce or Zr.



A catalyst for a fuel cell is formed from an alloy of composition PtAuX, where X is a transition metal such as Cr, Ti or Cu, with (in %): 40–97 Pt, 1–40 Au and 2–20 X. The alloy may be dispersed on a conductive C material to form a catalyst, an electrode may be formed from the catalyst deposited on an electrically conductive substrate, or a catalysed membrane formed from the catalyst deposited on a polymer electrolyte membrane.

213

Catalyst Layer for PEMFC

Enhanced Nucleation of Ru Films U.S. Appl. 2007/0,099,066

CANON KK

An electrode catalyst layer for a PEMFC has an entangled (‘cobweb-like’) structure formed by reducing a thin film layer containing Pt or a Pt alloy and O plus N and/or B. The entangled structure has thickness 3–100 nm and porosity 30–95%, and may be carried on a support such as C, Pt/C, Pt alloy/C, Pt black, Pt particles, Pt alloy particles or Au particles. Manufacture of Platinum Nanoparticles Using Plasma AJOU UNIV. IND. COOP. FOUND.

Korean Appl. 2007-0,010,715

Pt nanoparticles for an electrode catalyst in a fuel cell are synthesised using plasma technology. A Pt compound is dissolved in water with an acid and a base in a plasma reactor. H2(g) and an inert gas are mixed and injected into the reactor. Direct or alternating current or microwave energy are applied via two electrodes, placed at the solution side and the gas side respectively, causing plasma discharge at the interface between the Pt-containing solution and the mixed gas to induce reduction to Pt nanoparticles.

CORROSION PROTECTION Corrosion-Resistant Plating Structure GNC CO LTD

Korean Appl. 2007-0,021,601

A plastic material such as a resin or an engineering plastic is plated with a chemical plating layer of Ni or Cu to provide conductivity, a layer of Cu, a layer of Ag and layers of Pt, Pd, Rh or Ru to provide corrosion resistance. Formation of pin holes during the plating process is reduced, and galvanic corrosion is suppressed in a salt water environment.

CHEMICAL TECHNOLOGY

U.S. Patent 7,211,509

NOVELLUS SYSTEMS INC

A Ru layer can be deposited on a dielectric substrate by exposing the substrate to an amine-containing compound then to a Ru precursor (such as ruthenocene, Ru(acac)3, Ru(CO)5, etc.), and an optional oxidising or reducing coreactant. The aminecontaining compound facilitates nucleation on the dielectric surface. Magnetic Recording Medium FUJIFILM HOLDINGS CORP

Japanese Appl. 2007-018,625

A magnetic recording medium has a B2 metal alloy seed layer, an underlayer of Ru and a magnetic layer of CoPt coated on the surface of a non-magnetic supporting body. The seed layer has a column structure with diameter 5–20 nm and its surface is oxidised. The B2 metal alloy may consist of M:Al in the ratio 50:50, where M = Ru, Pd, Pt, Rh, Ir, Os, Ni, Fe or Mn. Diphasic Magnetic Nanomaterial HEBEI UNIV. TECHNOL.

Chinese Appl. 1,943,923

A magnetic nanomaterial Sm2Fe17N3-Fe3Pt, with crystal diameter ≤ 30 nm, includes a matrix phase of retentive 2:17 type rare earth Fe nitride with finely dispersed nanoparticles of body-centred non-retentive Fe3Pt. The method of preparation includes the steps of smelting 2–3 times at 50–300 A for 2–3 min; melting by high-frequency inductance coil in a quartz tube; pre-annealing at 350ºC and 5 × 10–3 Pa for 30 min; crystallising at 5 × 10–4 Pa and 700–800ºC for 25 min; and cracking and nitriding at 480ºC and 1 atm for 6 h. The material is claimed to give higher magnetic performance than monophasic retentive magnetic materials.

Leaching Process for the Recovery of Metals ANGLO OPERATIONS LTD

World Appl. 2007/074,360

A metal such as a Pt group metal, Au, Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K or Ca can be leached from an ore in the presence of HCl to form a soluble metal chloride salt. H2SO4 and/or SO2 are added to the leach solution during or after the leaching step, and a solid metal-sulfate or -sulfite salt is recovered. HCl is regenerated and continuously transferred to the vapour phase, and is then captured and returned to the leaching step.

ELECTRICAL AND ELECTRONIC ENGINEERING Plating Printed Circuit Board YMT CO LTD

U.S. Appl. 2007/0,104,929

A PCB is plated as follows. A bare soldering and a wire bonding portion made from Cu or Cu alloy are coated with a Pd or Pd alloy layer, then a Au or Au alloy layer, by electroless deposition. The Pd alloy layer may contain 91–99.9 wt.% Pd and the balance P or B, and has thickness 0.05–2 μm. The Au alloy layer may contain 99–99.99 wt.% Au with Tl, Se or a mixture, and have thickness 0.01–0.25 μm. The method may be used to coat rigid, flexible or rigid-flexible PCBs.


MEDICAL USES Combination Therapy Using Satraplatin GPC BIOTECH AG

World Appl. 2007/054,573

A combination therapy for prevention or treatment of cancer or tumours uses a packaged pharmaceutical including a Pt-based chemotherapeutic agent such as satraplatin, plus an inhibitor of a EGFR family receptor or a chemotherapeutically active pyrimidine analogue. The two components are administered within about 14 days of each other. Implantable Palladium Alloy Medical Device COOK INC

World Appl. 2007/070,544

An implantable medical device includes at least one portion made of a radiopaque Pd alloy, preferably containing ≤ 20 wt.% Re or alternatively (in wt.%): ≤ 10 Ru; ≤ 30 Rh; ≤ 30 Ir; 10–20 Pt; ≤ 30 Mo; ≤ 30 W; ≤ 20 Ta; 10–50 Ag; 10–50 Ag plus 5–10 Cu; ~ 26 Ag plus ~ 2 Ni; ≤ 20 Re plus ≤ 30 W; or 9.5 Pt, 9 Au, 14 Cu plus 32.5 Ag. The radiopacity is at least equivalent to that of Pt-8 wt.% W, ultimate tensile strength is > 200 ksi and elongation to fracture is ≤ 5%. The device may be a wire guide, embolisation coil, marker band, stent, filter, RF ablation coil or an electrode.

214

NAME INDEX TO VOLUME 51 Page

AbdelDayem, H. M. 138 Abdelsalam, M. E. 208 Acres, G. J. K. 34 Aelterman, W. 158 Ager, D. J. 172, 174 Akatsuka, T. 95 Akita, S. 156 Aksoylu, A. 27 Algieri, C. 47 Al-Hashimi, M. 209 Allègre, G. 96 Andrés, R. 210 Antolini, E. 211 Arblaster, J. W. 130 Archer, I. 83 Arendse, M. 36 Arnal, P. 185 Arnold, L. 147 Arnold, P. 176 Aryasomayajula, L. 96 Ashley, M. 116, 164 Astruc, D. 71 Atanasoski, R. T. 158 Auberson, A. 202 Aubert, C. 77 Azam, L. 97

Baiker, A. 95 Bakhru, H. 209 Balcar, H. 71 Ball, S. 204 Balme, G. 76 Banerjee, I. A. 49 Bannat, I. 46 Bañuelos Romero, F. 48 Baranoff, E. 208 Barbieri, G. 47 Barnett, N. W. 96 Bartlett, P. N. 208 Bartley, J. K. 44 Basset, J.-M. 185 Basso, A. 21 Battaini, P. 19, 200 Batten, S. R. 208 Baumberg, J. J. 208 Bazula, P. 185 Bedford, R. B. 187 Behzadi, B. 95 Bell, E. 22 Bellemin-Laponnaz, S. 176 Beller, M. 185 Bello, I. 49

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Benabdellah, M. Bencze, L. Benitez, M. Bergens, S. H. Berk, B. Bernardo, P. Bespalova, N. Bhargava, R. Bjorklund, R. Blacklock, T. J. Bo, Z. Bogdanov, D. Bolink, H. J. Bonakdarpour, A. Bond, G. C. Bondarev, O. G. Boonyanuwat, A. Borissova, A. Borodzinski, A. Botha, J. Botte, G. Bourikas, K. Bouteiller, B. Bouyssi, D. Boz, E. Brecq, G. Breit, B. Brintzinger, H.-H. Bruneau, C. Buc, D. Buratto, S. K. Busana, M. G. Busqué, F. Bussian, D. A. Bykov, V.

Cagnola, E. A. Calderazzo, F. Cambier, F. Cameron, D. S. Campo, J. A. Cano, M. Cao, F. Caps, V. Carmona, D. Carroll, L. J. Casas, E. Castarlenas, R. Catellani, M. Chan, K. S. Chandler, K. Chang, H. M. Chang, W. H.


95 69, 74 209 49 22 47 70, 73 147 209 210 46 156 208 158 48, 63 48 185 95 48 145 28 43 147 76 74 147 173 188 73, 77 49 158 49 209 158 74

48 187 44 27 46 46 46 43 187 156 209 73 187 95 204 96 49

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Chao, T. W. 96 Chaudhari, M. K. 148 Chauvin, Y. 36, 69 Chen, H. 210 Chen, P. 97 Chen, S. 211 Chen, T.-M. 47 Chen, W. 97 Chen, X. 95 Cheng, C.-L. 98 Cheng, W. 148 Chengfu, X. 46 Cheon, J. 98 Chi, Y. 96 Chifotides, H. T. 211 Chiusoli, G. P. 187 Choi, J. 98 Chou, P.-T. 96 Chu, X. 209 Chuepeng, S. 148 Chung, K.-I. 156 Citelli, D. 32 Cizmeci, M. 97 Clarke, M. L. 210 Clerici, M. G. 187 Colley, S. 84 Comin, E. 210 Comotti, M. 185 Copping, B. 2 Coq, B. 157 Cornish, L. A. 104, 189 Coronado, E. 208 Corro, G. 48 Corti, C. W. 19, 22, 199, 202 Crabtree, R. H. 176 Cukic, T. 42

Dafali, A. Dahn, J. R. Danopoulos, A. Daran, J.-C. de Jésus, E. de March, P. de Meijere, A. de Silva, A. P. de Souza, R. F. de Vries, J. G. Debe, M. K. Deffernez, A. Delagrange, S. Delaude, L. Denbratt, I.

95 158 176 97 210 209 76 36 210 16 158 43 157 71 145

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Deng, J. 98 Denmark, S. E. 210 Dent, A. J. 210 Dérien, S. 77 Derogatis, L. 32 Deubel, D. V. 211 Di Noto, V. 211 Díaz-Chao, P. 156 Diéguez, M. 158 Díez-González, S. 177 Ding, Y. 97 Diver, S. 176 Dixneuf, P. 70, 77 Dong, Q. 208 Dong, X. 49, 211 Douthwaite, R. 177 Dragutan, I. 69 Dragutan, V. 69, 177 Drioli, E. 47 Drozdzak, R. 71 Duan, D. 209 Duhayon, C. 97 Dunstan, D. E. 96 Durand, R. 157 Dus, R. 95 Dwyer, C. L. 188

Edlund, D. J. Edwards, P. El Kadiri, S. Ellis, S. Elsevier, C. J. Emge, T. J. Endoh, E. Erdler, G. Eriksson, M. Ernst, K.-H. Esteruelas, M. Evans, J. Evans, N. Evenson, C. R.

137 84 95 204 16 46 29 29 204 95 177 210 208 136

Faccenda, V. Fähler, S. Fakir, R. Feast, J. Feaviour, M. R. Federsel, H.-J. Feindel, K. W. Feldhoff, A. Feng, K. Feng, Q.

22 95 32 150 42 173 49 46 47 156

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Fensterbank, L. 77 Ferrer, I. J. 156 Ferri, D. 95 Fiddy, S. G. 210 Fierro, J. L. G. 48 Fink, G. 188 Finkelshtein, E. 73, 74 Finsterwalder, F. 28 Fischer-Bühner, J. 202 Fisher, T. S. 98 Flores, J. C. 210 Fogg, D. 70, 73 Font, J. 209 Force, C. 158 Fornasiero, P. 32 Fraile, J. M. 187 France, M. B. 210 Francioso, L. 209 Francis, P. S. 96 Franklin, A. D. 98 French, S. A. 54 Froom, S. 84 Frye, T. 20 Fu, G. 172 Fu, H. 210 Fuentes, J. A. 210 Fujii, H. 157 Fukuda, T. 46

Gade, L. Galenda, A. Gandon, V. Gang, C. Garcia Santamaria, S. García, H. Gautron, S. Gayatri Gebert, A. Ghiotti, G. Ghosh, R. Ghosh, S. Gielens, F. C. Giordano, R. Givord, D. Glisenti, A. Gliubizzi, R. Goddard, R. Goldman, A. S. Golunski, S. E. Gopalan, R. Gorman, B. A. Goto, S. Gottesfeld, S. Graetzel, M.

176 32 77 46 208 209 97 97 158 157 46 208 96 97 95 32 211 48 46 162 158 96 149 27 208

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Graham, M. J. 208 Graham, S. 157 Gray, P. 31 Grela, K. 71 Grice, S. 22, 201 Griffin, G. L. 96 Griffith, W. P. 150 Grigg, R. 76 Gringolts, M. 73, 74 Grohovskaya, L. G. 178 Gross, S. 211 Grubbs, R. H. 36, 69 Grzeszczak, P. 95 Guha, A. 158 Guil, J. M. 158 Guillet, B. 96

Hager, E. 128 Hall, G. S. 46 Hamilton, H. 136 Hammouti, B. 95 Hara, H. 49 Harada, C. 47 Harold, M. P. 157 Hasegawa, T. 95 Hauert, R. 95 Hawkins, R. 209 Hayase, S. 47 Haynes, A. 187 Heibel, A. 147 Helmersson, U. 49 Heras, J. V. 46 Herrmann, H.-O. 146 Hildbrandt, D. 32 Hill, A. 127, 199 Hirao, T. 157 Hisatsune, K. 211 Holderich, W. 84 Holmgreen, E. M. 157 Hong, H.-W. 47 Hong, S. 98 Hor, T. S. A. 128 Hormadaly, J. 49 Hou, Z. 97 Howard, P. 187 Hsieh, A. H. 96 Huang, J. 46 Huang, Y. S. 96, 98 Hudson, S. 29 Hultquist, G. 208 Hwang, S. 49

Ichinose, I. Ikariya, T.


46 172

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Ilkenhans, T. Imamoglu, Y. Imamoto, T. Incera Garrido, G. Ishibai, Y. Itagaki, M.

185 69 172 185 156 174

James, B. R. 208 James, S. L. 156 Janes, D. B. 98 Jennings, M. C. 156 Jentys, A. 185 Jeon, G.-H. 211 Jeon, M. K. 204 Ji, S. 32 Jian, S.-H. 98 Jiang, D. 97 Jiang, H. 209 Jiang, R. 211 Jiang, W. 210 Jiang, X. 210 Jin, C. 156, 157 Jin, J. 46 Johnson, B. F. G. 127 Johnson, D. 83 Jossifov, C. 73 Jun, M.-S. 98 Jun, Y. 98 Juneja, J. S. 209 Jung, C. H. 93 Jung, W. 95 Jyoti, B. 210

Kachi-Terajima, C. 95 Kado, T. 47 Kadyrov, R. 174 Kagan, H. 172 Kakeshita, T. 46 Kalck, P. 97 Kalyanasundaram, K. 208 Kandil, S. S. 208 Kaneko, M. 47 Kanzelberger, M. 46 Kappenberger, P. 95 Karhu, H. 209 Katakura, N. 47 Katib, S. M. A. 208 Kayahan, M. 97 Keep, A. K. 16, 204 Keurentjes, J. T. F. 96 Khosravi, E. 69, 73 Kim, C.-S. 32 Kim, H. S. 156

Page

Kim, H.-I. 211 Kim, J. 48 Kim, W.-S. 156 Kim, Y. 156 Kiserow, D. J. 48 Klein, C. 208 Klingvall, R. 204 Klotz, F. 200 Kochubey, D. I. 209 Kohbara, M. 95 Kolb, G. 28 Kono, M. 47 Kordas, K. 209 Kozak, M. 149 Krantz-Rülcker, T. 209 Kraushaar-Czarnetzki, B. 185 Kubokawa, M. 98 Kulinska, A. 208 Kündig, A. A. 158 Kurashima, K. 46 Kureti, S. 185 Kuroda, S. 96 Kwak, J. 49 Kwon, Y. H. 211

Lamaty, F. 177 Lamprecht, D. 148 Lang, C. 23, 78 Lang, K. 148 L’Argentière, P. C. 48 Larsson, M. 145 Lassauque, N. 97 Laurenczy, G. 97 Lazuen Garay, A. 156 Le Berre, C. 97 Lebargy, S. 96 Lebedeva, V. I. 209 Ledoux, N. 71 Lee, C. 30 Lee, G. 49 Lee, J. K. 156 Lee, K. 49, 98 Lee, W.-Y. 32 Lee, Y. H. 49 Lei, M. 46 Lercher, J. A. 185 Li, H. 148 Li, J. 97 Li, J.-H. 48 Li, L. 98 Li, W.-C. 97 Li, X. 210 Li, Y. 48 Lian, C. 98

216

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Liao, J. 98 Liew, K. Y. 97 Lim, N.-Y. 32 Lim, S. 98 Lim, T.-W. 32 Lin, I. 176 Lin, Q. 210 Lin, W. 211 Lindsey, K. 22, 199 Linkov, V. 32 Liprandi, D. A. 48 Liu, C. 49 Liu, C. J. 96 Liu, H. 210 Liu, J. H. 204 Liu, Q. 48 Lo, S. H. Y. 157 Loginov, Yu. N. 178 Lohwongwatana, B. 201 Lorenzini, F. 208 Lorret, O. 157 Lu, A.-H. 97 Lu, T. 49 Lu, T.-M. 209 Lu, W. 158 Luciano, R. H. 211 Lundström, I. 204 Lunsford, J. H. 48 Luo, H. 97 Luo, Y.-H. 46 Lysenko, Z. 98

Maccato, C. 211 Maerz, J. 200 Maggiore, A. 32 Mahajan, S. 208 Mahmood, A. 204 Maier, W. F. 93, 204 Maitlis, P. M. 187 Mäki-Arvela, P. 44 Malacria, M. 77 Mallick, K. 3 Manchanda, D. 202 Mann, M. 199 Mao, L. 157 Mao, Z. 98 Mar, R. E. 158 Marks, T. J. 36 Marques, H. M. 36 Marty, A. 95 Maruyama, K. 97 Maschmann, M. R. 98 Mata, Y. 158 Matyjaszewski, K. 74 Maughon, B. R. 98

Page

McCloskey, J. 21 McKeer, I. 202 Méchin, L. 96 Menegazzo, N. 156 Mertens, N. 158 Metiu, H. 158 Mikkola, J.-P. 209 Miller, D. 23 Mills, A. 52 Milton, E. J. 210 Minteer, S. 34 Mirkin, M. V. 47 Mishima, Y. 97 Mitchell, C. 83 Mitsuka, M. 46 Miyagishi, S. 156 Miyamae, N. 98 Mizaikoff, B. 156 Mochida, I. 98 Mokhtar-Zadeh, T. 98 Monteiro, N. 76 Montini, T. 32 Morandi, S. 157 Moreno, A. 32 Morris, G. 187 Moser, M. 22 Moss, J. R. 127, 128 Motonaka, J. 97 Mshumi, C. 78 Mukherjee, P. S. 208 Müllen, K. 85 Müller, T. J. J. 76, 77 Mundschau, M. V. 136 Murakami, H. 96 Muraza, O. 44 Murotani, H. 97 Murrer, B. 150 Musa, O. 74 Musavi, A. 97

Nair, B. K. R. 157 Nandy, T. K. 46 Narayan, R. J. 156, 157 Natile, M. M. 32 Navarro, M. 211 Nazeeruddin, Md. K. 208 Negishi, E. 76 Negro, E. 211 Nekrasov, I. A. 156 Nemoto, J. 47 Newman, D. M. 93 Newton, M. A. 210 Ni, C. 158 Nicoletti, S. 96


Page

Niemeyer, J. 32 Nishikawa, T. 156 Nishiyama, H. 173 Noda, Y. 95 Nolan, S. P. 70, 177 Nooten-Boom, A. 21 Nordlander, E. 128 Nowakowski, R. 95

O’Brien, P. O’Dea, J. R. Ogomi, Y. Oguma, M. Ohba, T. Okamoto, Y. Ormerod, D. Oro, L. A. Otsuki, J. Ozkan, U. S.

47 158 47 149 46 95 158 187 95 157

Pace, G. 211 Paciello, R. 173 Paglieri, S. N. 136 Pàmies, O. 158 Panfilov, P. 208 Papadimitrakopoulos, F. 46 Park, G.-G. 32 Park, I.-S. 156 Park, J. 174 Park, J. T. 49 Park, J.-S. 32 Park-Ross, P. 23 Pascual, A. 156 Patcas, F. C. 185 Patil, N. T. 76 Patrick, B. O. 208 Patrick, G. 32 Paul, M. 185 Pearson, S. 176 Pekerar, S. 211 Peng, M.-L. 47 Peng, X. 46 Pérez, H. A. 211 Pérez-Balado, C. 158 Pérez-Castells, J. 77 Peris, E. 177 Petrova, I. V. 209 Philipps, S. 32 Pichon, A. 156 Pietraszuk, C. 73 Pimanpang, S. 209 Pinilla, E. 46 Plyasova, L. M. 209

Page

Poinsignon, C. 95 Poletto, F. 32 Pollock, T. M. 46, 156 Potyrailo, R. A. 93, 204 Prada Silvy, R. 42 Prasad, K. 210 Prinetto, F. 157 Prins, S. N. 104 Prudenziati, M. 49 Pruschke, T. 156 Puddephatt, R. J. 156 Pugh, D. 176

Qi, A. Qu, J. Quiroga, M. E.

158 210 48

Raykhtsaum, G. 202 Reeve, R. 30 Regalbuto, J. R. 43 Regan, M. R. 49 Ren, L. 46 Repic, O. 210 Ricci, M. 187 Richardson, J. T. 43 Ring, Z. 209 Robbes, D. 96 Roberts, G. W. 48 Robinson, D. J. 36, 127 Robinson, I. M. 36 Robinson, T. V. 49 Roff, G. J. 210 Rojas, G. 74 Román, E. 158 Roth, S. 158 Rouleau, J. M. 158 Rudina, N. A. 209 Rüscher, C. H. 46 Russell, A. E. 30, 208

Sadler, P. J. Sahgal, S. Saitou, M. Sakaguchi, S. Sakurai, H. Sammells, A. F. Sammes, N. Sánchez, C. Sands, T. D. Sano, A. Sanz, J. Sato, J. Sauvage, X.

36 97 47 47 157 136 49 156 98 97 158 156 71

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Schaberg, P. 146 Scherf, U. 85 Schiraldi, D. A. 158 Schmid, U. 46 Schmoeckel, A. K. 158 Schofield, E. R. 42 Schott, F. J. P. 185 Schrock, R. R. 36, 69 Schultz, L. 158 Schulz, G. A. S. 210 Schumacher, J. O. 32 Schuster, H. 22 Schüth, F. 97, 185 Schütze, F.-W. 147 Schuurman, Y. 157 Schuyten, S. 204 Sclafani, J. 210 Scott, A. 98 Screen, T. 87 Scurrell, M. S. 3, 32 Seidel, H. 46 Seol, H.-J. 211 Serp, P. 97 Sessolo, M. 208 Shan, C.-C. 98 Shen, G. 209 Shim, J. H. 49 Shimizu, H. 173 Shiraishi, T. 211 Sibilia, G. 32 Siciliano, P. 209 Silva, C. 154 Singh, S. B. 97 Sivaramakrishna, A. 128 Smirnova, A. 49 Smith, R. C. 210 Soled, S. L. 43 Soloveichik, G. 204 Sommer, W. 177 Song, H. 49 Souche, Y. 95 Spassov, T. 95 Sprinceana, I. 32 Sproule, G. I. 208 Srivastava, M. 97 Stevens, D. A. 158 Steyn, J. 32 Stobbe, D. 46 Strauss, J. 22 Strukul, G. 187 Stuchlikova, L. 49 Studenok, G. I. 178 Suh, D. J. 204 Sullivan, A. C. 209 Sulman, E. 43 Sumodjo, P. T. A. 157

Page

Sun, E. J. 93 Sun, P. 47 Sun, Y. 175 Sung, Y.-E. 156 Sunley, G. 187 Süss, R. 104, 189 Svedberg, E. B. 93 Swan, N. 102 Sykes, R. 150

Takamizawa, S. 95 Takata, F. M. 157 Takei, Y. 47 Takuma, Y. 211 Tanaka, M. 46 Tanaka, Y. 211 Tandon, P. K. 97 Tani, K. 157 Tani, Y. 97 Taylor, A. D. 31 Taylor, D. K. 49 Tekin, A. 97 Ten Eyck, G. A. 209 Tereshchenko, G. F. 209 Teruel, L. 209 Thiébaut, D. 97 Tichit, D. 157 Tiekink, E. R. T. 49 Todorova, S. 95 Tokimoto, T. 95 Tong, H. D. 96 Torralba, M. C. 46 Torres, M. R. 46 Touzani, R. 95 Treacher, K. 84 Tryon, B. 156 Trzeciak, A. M. 128 Tsai, D.-S. 96, 98 Tsuji, M. 98 Tsuji, T. 98 Tsujimoto, M. 97 Tsujimura, T. 145 Tu, B. 47 116, 164 Tudor, R. Tudose, A. 71 Tulchinsky, M. L. 98 Tung, C.-H. 47 Türk, M. 185 Turner, D. R. 208 Turner, J. 149 Twigg, M. V. 43 Tymonko, S. A. 210

Upper, G.


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Vaivars, G. van der Lingen, E. van der Vaart, R. van Eldik, R. van Erkel, J. Varadan, V. K. Vasam, C. Veith, G. M. Verpoort, F. Virtanen, P. Volkov, V. V. von Zezschwitz, P. Vorstman, M. A. G. Vovard, C. Vuso, K.

32 32 209 36 209 96 176 44 71 209 209 76 96 71 23

Wagener, K. B. 69, 74 Wan, C.-C. 157 Wan, N. 98 Wang, C. 98 Wang, F. 98 Wang, G. 76 Wang, G.-C. 209 Wang, H. 97 Wang, L. 96 Wang, S. 96, 158 Wang, T. 97 Wang, Y. 48, 210 Wang, Y.-Y. 157 Wang, Z. 32 Wark, M. 46 Wasylishen, R. E. 49 Waters, J. 47 Watson, A. 104, 189 Wears, M. L. 93 Weck, M. 177 Weisheit, M. 95 Weisner, K. 22 Welker, C. 129 Whisenhunt, D. W. 204 Wiesner, K. 202 Willemsens, A. 158 Williams, B.-J. 20 Williams, J. A. G. 85 Wilson, J. R. H. 209 Winzer, K. 156 Witcomb, M. 3 Wodniecki, P. 208 Wolf, E. E. 204 Woo, S. I. 93, 204 Wright, J. 21 Wu, D. 158 Wu, J. 98 Wu, L.-Z. 47 Wu, P. 48

Page

Wu, Y. N.

96

Xie, J. Xie, X. Xie, Y.-X. Xing, W. Xu, B. Xu, Y. Xue, X.

96 136 48 49 97 48 49

Yabutani, T. 97 Yaghi, O. 36 Yamaguchi, A. 96 Yamaguchi, S. 31 Yamaguchi, Y. 47 Yamamoto, Y. 76 Yan, L. 97 Yang, H. 209 Yang, K. 48 Yano, R. 98 Yano, T. 95 Yarkandi, N. H. M. 208 Yasuzawa, M. 97 Yates, M. 42 Ye, F. 211 Yermakov, A. V. 178 Yi, S.-J. 211 Yoon, S.-H. 98 Yoon, Y.-G. 32 York, A. P. E. 145, 147 Youngs, W. 177 Yu, J. 68 Yu, R. 209 Yung, M. M. 157

Zanotti-Gerosa, A. 173 Zawodzinski, T. A. 158 Zhang, F. 156 Zhang, H. 98 Zhang, J. 98 Zhang, L. 95, 98 Zhang, L.-P. 47 Zhang, R.-Y. 47 Zhang, Y. 48, 98 Zhao, D. 47 Zheng, X. 97 Zhengfei, G. 46 Zhou, H. 157 Zhou, Y. 48 Zhu, G. 76 Zhu, H. 97 Zhu, J. 98 Zhu, Q.-M. 48 Ziegler, C. 32

218

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a = abstract Acetic Acid, synthesis 97, 187 Acetylenes, Sonogashira coupling 87 ADMET, Grubbs catalyst 69 Alcohols, C12 to C15 alcohols, production 164 2-ethylhexanol, production 116, 164 EtOH, reforming 34 fuel 34, 145 MeOH, carbonylation, a 97 sensor 3 1-octanol, production 164 oxidation 49, 97, 98, 204, 211 electro-, a 49, 211 selective, a 97 2-propylheptanol, production 164 Aldehydes, by hydroformylation 116, 164 cyclisation 16 α,β-unsaturated, hydrogenation, a 209 Alkanes, dehydrogenation 63, 136 isomerisation 63 Alkenes, in reactions 16, 63, 69, 76, 97 Alkylation 76, 176 Alkynes, reduction 16 Amines, pure enantiomers, synthesis 83 Amino Acids, pure enantiomers, synthesis 83 Ammonia, + CH4, HCN synthesis, a 157 decomposition, a 47 sensors 204 Annealing, Pt 178 Anthracene, oxidation, a 97 Antimalarial Agents, Ir chloroquines, a 211 Arenes, reduction 16 Aryl Halides, in reactions 83, 87, 127, 172, 210 Arylboronic Acids, in coupling reactions 83, 87, 210 Autocatalysts 34, 87, 154, 162

Catalysis, (cont.) biphasic, a 210 book reviews 16, 76, 176, 187, 204 conferences 36, 42, 69, 83, 127, 145, 172, 185 heterogeneous, a 48, 97, 157–158, 209–210 homogeneous, a 48–49, 97–98, 158, 210 in ionic liquids 127, 209, 210 Catalysts, activity, effects of particle size variation 63 dendrimers, a 210 ‘non-passive’ support 127 phase separation 16 poisons 162 production, using a plasma torch 42 recycling 83, 87, 162, 209, 210 supported ionic liquid (SILCA) 42, 209 supported metal 42 three-way, see Three-Way Catalysts Catalysts, Iridium, electrocatalysts, Pt-IrNT, Pt-IrO2NT, Pt-Ir-IrO2NT, MeOH oxidation, a 98 RuO2-IrO2/Pt, for URFCs, a 98 Pt-Ir, coal electrolysis 27 petroleum reforming 63 Catalysts, Iridium Complexes, CativaTM process 187 hydrogenation: enantioselective, homogeneous, transfer 16 Ir-BisP*, Ir-MiniPhos*, imine reduction 172 IrCl3, + H2O2, oxidation of organic compounds, a 97 MeOH carbonylation, a 97 Catalysts, Osmium Complexes, conference 36 H2Os3(CO)10, derivatives, asymmetric hydrogenation 127 Os3(CO)12, derivatives, asymmetric hydrogenation 127 Os-NHC 69, 176 OsO4, dihydroxylation of 1,2-dioxines, a 49 Catalysts, Palladium, Au-Pd/C, Au, Pd deposition 42 Cu-Zn-Pd, MeOH partial oxidation 204 electrocatalysts, Pd, Pd-Co, Pd-Co-Au, ORR 27 Pd, (+ H2), anode, for PEFC 27 Pd coatings, anodes, for SOFCs 27 Pd-Co/C, ORR activity, a 98 Pt-Pd, cathodes, for DEFCs, a 211 Pd-based sulfated zirconia, lean NOx reduction, a 157 Pd membrane reactors, WGSR 136 Pd nanoparticles, encapsulated, porous polyurea beads 83 preparation 42 Pd nanoparticles/Al hydroxide 172 Pd nanoparticles/ionic liquid layer/active C cloth, a 209 Pd perovskites, in autocatalysts, self-regenerating 87 in organic synthesis: Sonogashira, Suzuki coupling 87 Pd/α-Al2O3, /γ-Al2O3, pellets, preparation, in L-CO2, a 48 Pd/Al2O3, preparation, for hydrogenations 42 reforming of glycerol 185 soybean oil hydrogenation, a 97 Pd/C, imine reduction 83 Pd deposition 42 soybean oil hydrogenation, a 97 Pd/membrane, alkane dehydrogenation 136 Pd/ordered mesoporous C, selective oxidation, a 97 Pd/oxide supports, reforming of EtOH 34 48 Pd/SiO2, direct formation of H2O2, a Pd/support, selective hydrogenation of ethyne, a 48 Pd-Au, selective oxidation, alkenes, H2, reducing sugars 63 Pd-Pt nanoparticles, preparation 42 Pd-Cu/hydrotalcite, reduction of nitrate, a 210 Pd-LM-SiO2, hydrogenation of nitrobenzene 3 Pt-Pd, Pt-Pd/zeolite, S resistance, a 209 three-way 162 Catalysts, Palladium Complexes, allylpalladium(II) 76, 210 carbonylations, atom-efficient 185 conference 36 coupling reactions 185, 187 synthesis, boscalid, sartans 187 + ferrocene units, Suzuki couplings 127 homogeneous hydrogenation 16

Benzaldehydes, oxidation, a 97 Benzene, reduction 16 Biaryls, preparation, a 210 Boiling Points, Ir, Os, Pd, Pt, Rh, Ru 130 Book Reviews, “Alcoholic Fuels” 34 “Combinatorial and High-Throughput Discovery and Optimization of Catalysts and Materials” 93, 204 “Handbook of Homogeneous Hydrogenation” 16 “Metal-catalysis in Industrial Organic Processes” 187 “Metal Catalyzed Cascade Reactions” 76 “Nonporous Inorganic Membranes” 136 “Organic Light-Emitting Devices” 85 “Recent Developments in the Organometallic Chemistry of N-Heterocyclic Carbenes” 176 “The Separation and Refining Technologies of Precious Metals” 68 Buchwald-Hartwig Couplings 172 Bulk Metallic Glasses, 850 Pt 199 Butene, hydroformylation 164 Butyraldehydes, by hydroformylation of propylene 116, 164 Cancer, anti-, pgm complexes 36, 211 Carbenes 69, 76, 176 Carbon Oxides, CO, adsorption, Pd-Au, Pt-Au films, a 95 electrooxidation, a 49 116, 164 + H2, hydroformylation of propylene hydrogenation, a 97 oxidation 47, 162, 185 CO2, methanation 42 reduction 16 supercritical, solvent 185 tolerance, of PEFC anodes 27 Carbonylation 83, 97, 185, 204 Cascade Reactions 76, 157 Casting, jewellery alloys 19, 102, 199 Catalysis, asymmetric 48, 54, 98, 127, 158, 172, 176, 187


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Catalysts, Palladium Complexes, (cont.) Pd, migration/insertion into C–H bonds 76 Pd(0), cascade reactions 76 Pd(0) complex/polysiloxane capsule, a 97 204 Pd(acac)2, carbonylation of phenol Pd(II) acetate/phosphines, encapsulated in beads 83 [PdCl(COD)] + base, methoxycarbonylation 127 PdCl2, + H2O2, oxidation of organic compounds, a 97 [PdCl2{P(OPh)3}2] + base, Sonogashira coupling 127 Pd + dcpmp, Suzuki couplings, a 210 Pd dendrimers, a 210 Pd(dppb)2, carbonylation of phenol 204 TM Pd(II) EnCat BINAP30, Suzuki coupling 83 Pd ethylthioglycolate modified silica, a 209 Pd-NHC 69, 176 Pd(OAc)2, hydrogenation of NBR, a 210 Pd(OAc)2 + BINAP, Buchwald-Hartwig coupling 172 Pd(OAc)2/DABCO, Suzuki-Miyaura cross-crouplings, a 48 Pd(PPh3)4, for 2-chloro-5-(pyridin-2-yl) pyrimidine, a 158 Pd-phosphine (+ PVP), ethene carbonylation, in MeOH 83 Pd + Ph3P(O), coupling of K aryldimethylsilanolates, a 210 Pd + phosphite-oxazoline ligands, Heck reactions, a 158 Pd-Rh, PKR substrate generation and processing 76 Pd-Smopex-111, Suzuki reactions, a 210 Pd/SILCA, citral hydrogenation 42 Pd(o-Tol)4, conversion of an aryl bromide, to nitrile 172 reduction, CO2 16 Catalysts, Platinum, base metal oxide-doped Pt/C 204 electrocatalysts, Pt, for fuel cells 27, 34, 211 inks, deposition, ink jet technology 27 Pt black, cathodes, for PEMFCs, a 49 Pt-coated AFM tip, cathode, for PEMFC, a 158 Pt coatings, anodes, for SOFCs 27 Pt containing, for fuel cells 204, 211 Pt/activated C, for PEMFCs, a 158 Pt/C, cathodes, for DMFCs 27 inks, deposition, ink jet technology 27 Pt/C-aerogel, for PEMFCs, a 49 Pt/C cloth, cathodes, for PEFC 27 Pt/C nanocatalysts, for fuel cells, a 49 Pt/C nanofibres, for PEMFCs, a 158 Pt/Nafion ‘inks’, electrodes, for PEFCs 27 Pt-Au, cathodes, O reduction, in fuel cells 63 Pt-Co/C, PtMo/C, electrodes 27 Pt-IrNT, Pt-IrO2NT, Pt-Ir-IrO2NT, MeOH oxidation, a 98 Pt1–xMx, M = Au, Co, Mo, Ru, Sn, Ta, PEMFCs, a 158 Pt-Ni carbon nitride, a 211 Pt-Pd, cathodes, for DEFCs, a 211 PtRu, see Catalysts, Ruthenium Pt-Sn, binary, ternary: anodes, for DEFCs, a 211 Pd-Pt nanoparticles, preparation 42 Pt, coal electrolysis 27 185 conversion of NOx; reduction of NOx, by H2 decompostion, Na borohydride 27 role, catalytic converters 162 S resistance, a 209 Pt black, HCN, synthesis, a 157 Pt nanoparticles, preparation 42 Pt/γ-Al2O3, diesel soot oxidation, a 48 Pt/Al2O3, H2/NOx reaction 185 reforming of glycerol 185 Pt/C, electrochemical oxidation of borohydride 27 HDCl of DCE 138 preparation 42, 138 Pt/Mg(Al)O, synthesis; cascade reaction, a 157 Pt/SnO2 (Pt via scCO2 deposition), CO oxidation 185 Pt-Au, NO reduction, by propene 63 selective oxidation: polyols, reducing sugars 63 Pt-Ir, coal electrolysis 27 petroleum reforming 63 Pt-Pd, S resistance, a 209 Pt-Sn, alkane dehydrogenation 63 Pt-Au colloids/C, preparation 63 Pt-Au/HY zeolite, alkane isomerisation 63 Pt-Au/SiO2, /TiO2, /TiO2–SiO2, /Y zeolite, preparation 63

Catalysts, Platinum, (cont.) Pt2Au4/SiO2, preparation 63 PtCu/, PtCuCaH/, PtCuH2/, PtCuNaH/C, preparation 138 138 PtCuCaH/, PtCuH2/, PtCuNaH/C, HDCl of DCE Pt-modified TiO2, photooxidation of NOx, a 156 Pt-Ni/δ-Al2O3, indirect partial oxidation of LPG 27 Pt-Pd/zeolite, S resistance, a 209 Pt-Sn/γ-Al2O3, diesel soot oxidation, a 48 PtSnNa/ZSM-5, propane dehydrogenation, a 48 Ru-Pt clusters 127 RuPt nanoparticles/mesoporous SiO2, preparation 42 three-way 162 transition metal oxide-doped Pt/C 204 Catalysts, Platinum Complexes, conference 36 cyclometallated Pt(II)/SBA-15, olefin photooxidation, a 47 homogeneous hydrogenation 16 Catalysts, Rhodium, octane reforming 27 Rh/γ-Al2O3, oxidation by NO, reduction by H2, a 210 Rh/Al2O3, reforming of glycerol 185 Rh/CeO2, preparation, reduction/oxidation treatment, a 158 Rh/MgO/CeO2-ZrO2, reforming of gasoline, a 158 Rh/oxide supports, reforming of EtOH 34 Rh-Mn-Li-Ti/SiO2, CO hydrogenation, a 97 three-way 145, 162 Catalysts, Rhodium Complexes, asymmetric hydroformylation 187 asymmetric hydrogenation, synthesis: L-DOPA, (–)-menthol, (S)-metolachlor 187 bisphosphite-Rh complex, hydroformylation 164 catalyst reactivation 116 cationic, cyclisation of aldehydes, enones 16 conference 36 [Cp*RHCl2]2 + chiral diamine, H2O soluble, ATH, a 98 enantioselective hydrogenation 16 homogeneous hydrogenation 16 SM hydroformylation of olefins, LP Oxo Process 116, 164 hydrogenation, diene based polymers 16 modular P-chiral ligands, asymmetric hydrogenation, a 48 Monsanto process, acetic acid synthesis 187 NORMAXTM Catalyst, bisphosphite-Rh complex 164 Pd-Rh, PKR substrate generation and processing 76 reduction, arenes, CO2, heteroaromatics 16 Rh(I), alkylation of π-allyl species, cascade reactions 76 Rh(I)-chloride-hexylamine, semihydrogenation, a 48 Rh(acac)(CO)PPh3, as precursor 116 Rh-BisP*, Rh-MiniPhos, reduction reactions 172 RhCl3, + H2O2, oxidation of organic compounds, a 97 [Rh(COD)2]BF4 + modular P-chiral ligands, a 48 TM Rh-MonoPhos , reactions 172 Rh(Norphos), Rh(Phebox), Rh-QuinoxP*, Rh-Rophos, Rh-Solphos, Rh(TMBTP), reduction reactions 172 Rh-TPPTS, biphasic hydroformylation, a 210 rhodacycloalkanes, chain forming reactions 127 ROPAC + CO + triphenylphoshine, hydroformylation 116 SM SM SM 164 SELECTOR 10, SELECTOR 30, in LP Oxo TPP-Rh complex, hydroformylation 116, 164 transfer hydrogenation 16 Wilkinson’s catalyst 116, 150 Catalysts, Ruthenium, electrocatalysts, PtRu 34, 98, 158 binary, ternary: anodes, for DEFCs, a 211 PtRu/C, anodes, for DMFCs, PEFCs 27 Pt-Ru/CNTs, Pt-Ru-Ni/CNTs, for DMFCs, a 211 PtRu/C nanofibres, for DMFCs, a 98 PtRu/Vulcan C, for DMFCs, a 49 Pt-Ru black, anodes, for PEMFCs, a 49 Ru containing, for fuel cells 204, 211 RuO2-IrO2/Pt, for URFCs, a 98 Ru, decompostion, Na borohydride 27 Ru nanocatalysts, reduction of benzene 16 Ru nanoparticles 42, 97 Ru/Al2O3, C oxidation, in SOFCs 27 Ru/ceramic foam, CO2 methanation 42 Ru/SiO2, preparation, TEA as an impregnation aid 42 Ru-Pt clusters 127 RuPt nanoparticles/mesoporous SiO2, preparation 42


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Catalysts, Ruthenium Complexes, asymmetric hydrogenation, of ketones 54 cascade reactions 76 conference 36 enantioselective hydrogenation 16 Grubbs catalyst 69, 76, 98, 127 [H4Ru4(CO)8(P-P*)2], [H4Ru4(CO)10(P-P*)], H4Ru4(CO)12, asymmetric hydrogenation 127 homogeneous hydrogenation 16 Hoveyda’s catalyst 69, 76 hydrogenation, ketones 16 metathesis 69, 76, 176, 187 Nolan’s catalyst 69 Noyori’s catalyst 54 P-Phos, PhanePhos, ParaPhos 54 (PCy3)2Cl2Ru=CHPh, stability, a 98 reduction, arenes, CO2, heteroaromatics 16 Ru alkylidenes, allenylidene, indenylidene 69 Ru(BINAP), reduction of an unsaturated acid 172 Ru-BINAP-DPEN, ketone reduction 172 RuCl2(PPh3)3, hydrogenation of NBR, a 210 Ru clusters, Fischer-Tropsch reaction 127 Ru3(CO)12, derivatives, asymmetric hydrogenation 127 Ru-NHC 69, 76, 176 Ru-TolBINAP, Ru-XylBINAP, ketone reduction 172 transfer hydrogenation 16 [(S)-XylBINAP-RuH2-(S,S)-DPEN], modelling 54 TM Cativa Process, acetic acid synthesis 187 Clusters, Os, Ru, Ru-Pt 127 Coatings, Pt black, a 47 Pt-Ir modified aluminide, on Ni-base superalloy, a 96 Colloids, Pt-Au 63 Combinatorial Chemistry 93, 204, 211 Combustion, toluene 42 Composites, diamondlike C–Pt films, a 157 Pd-polyaniline, Pd-polyaniline derivatives 3 Compound Energy Formalism Model 104 Conferences, 4th Cape Organometallic Symposium, South Africa, 2006 127 9th Int. Symp. on the Scientific Bases for the Preparation of Heterogeneous Catalysts, Belgium, 2006 42 40th Conference ‘Deutscher Katalytiker’, 2007 185 Fuel Cells Science and Technology 2006, Italy 27 2007 Fuels and Emissions Conference, South Africa 145 ICCC37, Cape Town, South Africa, 2006 36 New Frontiers in Metathesis Chemistry, Turkey, 2006 69 Novel Chiral Chemistries Japan 2007 172 Sante Fe Symposium, U.S.A. 19, 199 Successful Scale-Up of Catalytic Processes, U.K., 2006 83 Corrosion, Pt-Ir modified aluminide coatings, a 96 Corrosion Inhibitors, for steel, Ru macrocycle, a 95 Coupling Reactions 185, 187, 210 Cross Metathesis 69, 98 Crucibles, Pt 178 CVD, aerosol-assisted, Pd sulfide thin films, a 47 Pd activation layers, a 96 Cyclisation, aldehydes, enones 16

Electrical Contacts, ohmic, Pd/C SWNTs, a 98 Electrical and Electronic Engineering, a 49, 98 Electrical Resistivity, Ti/Pt thin films, a 46 Electrochemistry, a 47, 95, 156 polyaniline-Pd composite films 3 Pt black coating, a 47 Pt–diamondlike C nanocomposite thin films, a 156 Pt nanoelectrodes, a 47 Pt nanoparticles/C powder, anode, in Li ion batteries, a156 Electrodeposition, CoPd thin films, a 157 Pd nanowires, a 98 Pt black coating, a 47 Electrodeposition & Surface Coatings, a 47, 96, 157, 209 Electrodes, in fuel cells, see Fuel Cells 209 GOx/Aunano/Ptnano/CNT, glucose sensor, a micro-, Pt, in wine classification, a 209 nano-, Pt, electron-transfer reactions, a 47 Pt nanoparticles/C powder, anode, Li ion batteries, a 156 Electroless Plating, Cu, Cu/Pd nanoparticles activator, a 157 Pd, membranes, a 157 Electrolytes, H2PtCl6, + Pb acetate trihydrate, a 47 Emission Control, motor vehicles 34, 87, 145, 154, 185 Enamines, enantiosective hydrogenation 16 Enones, cyclisation 16 Enynes, cycloisomerisation 69 metathesis 69, 76, 176 Ethene, carbonylation 83 hydrogenation, a 48 Ethyne, selective hydrogenation, ethene-rich streams, a 48

Decomposition, NH3, a 47 Deformation, Ir single crystals, a 208 Deformation Resistance, 99.93 wt.% Pt 178 Dehydrogenation, alkanes 48, 63, 136 Dendrimers, Pd, a 210 Density Functional Theory, modelling, Ru catalysts 54 Dental, alloys, hardening, a 211 Deposition, Co/Pt, CoCr/Pt thin films 93 electroless, Cu, Cu/Pd nanoparticles activator, a 157 plasma, Pd, on poly(p-xylylene), a 209 scCO2, Pt, on SnO2 185 1,2-Dichloroethane, hydrodechlorination 138 Diesel, emission control 145, 185 soot, oxidation, a 48 Dihydroxylation, 1,2-dioxines, a 49 Electrical Conductivity, nanofibrous Pt sheets, a


46

Field-Effect Devices, gas-sensitive 204 Films, diamondlike C–Pt composite, a 157 Pd-Au, Pt-Au, CO adsorption, a 95 polyaniline-Pd, electrochemical behaviour 3 Pt, porous, a 208 ‘Final Analysis’ 52, 102, 162 Fischer-Tropsch Reactions, Ru clusters 127 Fuel Cells, a 49, 98, 158, 211 DAFC, fuel 34 DEFC, electrocatalysts, anodes, cathodes, a 211 DMFC, catalysts 27, 34, 49, 98, 204, 211 fuels 27, 34, 204 high-throughput screening, catalysts 27, 204, 211 inks, Pt, deposition, ink jet technology 27 membrane electrode assemblies 27 O reduction 27, 63 PEFC, catalysts 27 PEMFC, catalysts 27, 34, 49, 158, 204 conducting channels, nanoscale current imaging, a 158 distribution of H2O, a 49 surface-modified C, as Pt catalyst support, a 158 SOFC, catalysts 27 URFC, electrocatalyst, a 98 Fuels, alcohols 34, 145 diesel; biodiesel 145 27, 145, 204 H2 natural gas 145 synthetic, BTL, CTL, GTL 145 Gas Recycle Principle, in LP OxoSM Gasoline, autothermal reforming, a Gauzes, N-based fertiliser production Glucose, sensor, a Glycerol, reforming

116, 164 158 34 96, 97, 209 185

Hardening, dental alloys, a 211 Hardness, 99.93% Pt 178 Pt-5% Co 102 Pt-5% Cu 78, 102 Pt-5% Ir, Pt-5% Pd, Pt-5% Ru 102 Heck Reactions 76, 83, 97, 158, 209, 210 1-Heptyne, semihydrogenation, a 48 Heteroaromatics, reduction 16 High-Throughput Screening Techniques 27, 93, 204, 211 History, Sir Geoffery Wilkinson, commemorative plaque 150

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Hydride, reduction, Pt-Cu/C, synthesis 138 Hydrocarbons, oxidation 162 Hydrodechlorination, 1,2-dichloroethane 138 Hydroformylation 187, 210 SM 116, 164 low-pressure Rh-based catalyst, LP Oxo Hydrogen, + CO, hydroformylation of propylene 116, 164 for direct formation of H2O2, a 48 from reforming, glycerol 185 fuel 27, 145, 204 -induced stress relaxation, in thin Pd films, a 95 membranes 96, 136, 157 + NOx, reduction 185 production 27, 204 purification, a 47 selective oxidation 63 sensors 204 sorption, of Mg–(Ir,Rh,Pd)–Si, a 95 Hydrogen Cyanide, synthesis, a 157 Hydrogen Peroxide, formation 48, 63 Hydrogenation, asymmetric 48, 54, 127, 187 asymmetric transfer 98, 172 CO, a 97 diastereo-; enantio-; enantioselective transfer 16 diene based polymers 16 ethene, a 48 homogeneous 16 ketones 16 nitrile rubber, a 210 nitrobenzene 3 O2, in H2O, a 209 partial, citral 42 selective, a 48 soybean oil, a 97 transfer 16 α,β-unsaturated aldehydes, a 209 Hydrotalcite, Pd-Cu/hydrotalcite, reduction of nitrate, a 210

Liquid Crystals, pyrazole-based allyl-Pd complexes, a 46 Liquid Recycle Principle, in LP OxoSM 164 Liquidus Surface, Pt-Cr-Ru 189 SM ‘LP Oxo Process’, hydroformylation of olefins 116, 164 LPG, indirect partial oxidation 27 Luminescence, Ir(III) complexes, a 47, 157, 208 Ru complexes, a 96, 209

Imines, hydrogenation 16, 98 reduction 83 Ink Jet Technology, deposition, Pt catalysts, for MEAs 27 Inks, Pt catalysts, for MEAs 27 Ionic Liquids 127, 209, 210 Iridium, boiling point, melting point 130 Pt-Ir modified aluminide coatings, a 96 refining 68 in sensors 204 single crystals, deformation, a 208 Tammann temperature 162 vapour pressure equation, vapour pressure value 130 Iridium Alloys, Pt-5% Ir, hardness 102 Iridium Complexes, Cp*IrClL2, precursor, for Cp*IrLR2 127 iridacycles, by RCM 127 Ir chloroquines, antimalarial agents, a 211 trans-IrCl(CO)L2, as precursor to tricarbido complexes 127 fac-[Ir(ppy)3], alkyl chains, ordered arrays, graphite, a 95 luminescence, a 47, 157, 208 OLEDs 85, 96, 208 (PCP)Ir(NBE), + N2; (PCP)IrPhH, + N2; (PCP)Ir(N2), a 46 phosphorescence, a 96, 208 photoconversion 36 Iridium Compounds, IrO2, in propionic acid sensor, a 96 Mg–(Ir,Rh,Pd)–Si, H sorption, a 95 Isomerisation, alkanes 63 cyclo-, enynes 69 Isothermal Section, calculated, Pt-Cr-Ru 189 Jewellery, Pd, Pd alloys 19, 199 Pt alloys 19, 23, 78, 102, 199 Johnson Matthey, Autocatalyst Plant, South Korea 154 Pd jewellery alloys 19, 199 “Platinum 2006 Interim Review” 45 “Platinum 2007” 155 Platinum Metals Rev. Journal Archive 2 Ketones, hydrogenations


16, 54, 98, 172

Magnetic Storage, Co/Pt, CoCr/Pt, CoCrPtTa, PtCo, PtFe 93 CoPt3 nanoparticles, FePt nanoparticles, a 98 Magnetism, CoPd thin films, a 157 CoPt nanoparticles, a 49 CoPt3, FePt nanoparticles, a 98 FePd, FePt, a 95 Fe35Pt35P30, Fe50Pt50, Fe53Pt44C3, a 158 [Rh2(bza)4(pyz)]n + NO, a 95 Martensitic Transformation, FePd, a 46 Mechanical Properties, Pt-5% Cu 78 Medical, Pd, Pt, Rh, Ru complexes 36 Medical Uses, a 158, 211 Melting Points, Ir, Os, Pd, Rh, Ru 130 Pt 130, 162 Membranes, Pd 96, 136, 157 Pd/polypropylene fibre, hydrogenation of O2, a 209 Pd-Ag, tubular; Pd-Cu, foil 136 PGM (+ ceramic oxide), PGM coatings, PGM alloy 136 Pt-loaded zeolite, for H2 purification, a 47 Si3N4/SiO2 radiometer, Pt thin film thermometers, a 96 Metathesis 69, 76, 176, 185, 187 Methanation, CO2 42 Methane, + NH3, HCN synthesis, a 157 Methoxycarbonylation, iodobenzene 127 Methyl Methacrylate, production, scale-up 83 Microwaves, -polyol method, preparation of PtRu/CNF, a 98 in Suzuki cross-couplings, a 210 MOCVD, nanostructured IrO2 crystals, a 96 Modelling, reactions, chiral Ru catalysts, using DFT 54 Monosaccharides, oxidation 42 Monsanto Process, acetic acid synthesis 187 Nanocatalysts 49, 127 Nanocomposites, Pt–diamondlike C thin films, a 156 Nanoelectrodes, Pt, a 47 Nanofibrous Sheets, Pt, electrical conductivity, a 46 Nanoparticles, CoPt, a 49 CoPt3, a 98 Cu/Pd, a 157 FePt, a 98 Pd 3, 36, 69, 83, 172, 209 Pt, a 46, 96, 156, 209 Ru 36, 97 96 Nanostructures, IrO2 crystals, by MOCVD, a Nanowires, Pd, a 98 Negishi Couplings, a 158 Nitrate, reduction, a 210 Nitrobenzene, hydrogenation 3 Nitrogen, adsorption, by [Rh2(bza)4(pyz)]n, a 95 Nitrogen Oxides, NO, adsorption, by [Rh2(bza)4(pyz)]n, a 95 interaction with Rh/γ-Al2O3, a 210 reduction, by propene 63 NO2, adsorption, by [Rh2(bza)4(pyz)]n, a 95 NOx, photooxidation, a 156 reduction 157, 162, 185 traps 145 Oil, soybean, hydrogenation, a 97 OLEDs 85, 96, 208 Olefins 47, 48, 69, 127, 164, 185, 187, 210 Osmium, boiling point, melting point 130 refining 68 Tammann temperature 162 vapour pressure equation, vapour pressure value 130 Osmium Complexes, in biology 36 Os pyridylazolates, in OLEDs, a 96 tris-bipyridine Os pyrrole complexes, glucose sensor, a 97

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Oxidation, alcohols 49, 97, 98, 204, 211 anthracene, a 97 benzaldehydes, a 97 CO 162, 185 cyclic, Ru single crystal superalloys, a 156 diesel soot, a 48 electro-, CO, a 49 alcohols, a 49, 211 hydrocarbons 162 indirect partial, LPG 27 metals, Pt-catalysed, a 208 partial, MeOH 204 phenanthrene, a 97 PtRuAl, RuAl, a 46 158 Rh/CeO2, a selective, alcohols, a 97 alkenes, H2, reducing sugars 63 CO, a 47 monosaccharides 42 Oxygen, for direct formation of H2O2, a 48 in H2O, hydrogenation, a 209 reduction, a 98, 211 in fuel cells 27, 63 Oxygenates, C2-, from CO hydrogenation, a 97

Pauson-Khand Reactions, substrates 76 Perovskites, pgm, preparation; autocatalysts; catalysts 87 Petroleum, reforming 63 Phase Diagrams, Al-Pt, Al-Ru 104 Cr-Pt 104, 189 Cr-Ru 189 Fe–Pt–Nd, a 46 Pt-Au 63 Pt-Ru 189 Phenanthrene, oxidation, a 97 Phenols, carbonylation 204 Phosphoramidites, in catalysis 16 85 Phosphorescence, Ir(btp)2(acac), Ir(ppy)3, PtOEP Ir(III) complex, a 208 Ir, Os, Pt, Ru 2-pyridylazolates, a 96 Photoconversion, a 47, 96, 156–157, 208–209 Ir, Pd, Pt, Ru complexes 36 Photooxidation, NOx, a 156 olefins, a 47 Photoproperties, Ir, Os, Pt, Ru 2-pyridylazolates, a 96 Photosensitisers, black dye/, N3/TiO2, for solar cells, a 47 2+ Ru(bpy)3 , decomposition of NH3, a 47 Photovoltaic Materials, PdS thin films, a 156 Photovoltaic Properties, tris(bpy)Ru-silica, a 209 Plasma, deposition, Pd, on poly(p-xylylene), a 209 torch, for catalyst production 42 Plating Baths, chloride, Co2+, Pd2+, a 157 Platinum, annealing 178 black 47, 52 boiling point 130 crucibles 178 diamondlike C–Pt composite films, a 157 electrodes, see Electrodes magnetic storage 93, 98 melting point 130, 162 membranes 47, 136 nanofibrous sheets, conductivity, a 46 nanoparticles, a 46, 96, 156, 209 in oxidation of metals, a 208 phase diagrams 46, 63, 104, 189 porous morphologies; black, platinised, sponge 52 99.93 wt.% Pt, annealing; deformation resistance 178 Pt, Pt-Au films, CO adsorption, a 95 Pt-Al-Cr-Ru, thermodynamic database 104 Pt-Al-Ru, liquidus surface projections 104 Pt-Cr-Ru 104 isothermal section, calculated; liquidus surface 189 Pt-Ir modified aluminide coatings, a 96 recycling 162 refining 68 in sensors 204 Tammann temperature 162 thin films, see Thin Films vapour pressure equation, vapour pressure value 130 Platinum Alloys, Au-Pt, diffusion bonding 19 casting, for jewellery 19, 102, 199 dental, hardening, a 211 Fe35Pt35P30, Fe50Pt50, Fe53Pt44C3, corrosion, a 158 jewellery 19, 23, 78, 102, 199 nanoparticles, a 49, 98 Nd3Pt4 phase, a 46 850 Pt, bulk metallic glass 199 Pt84:Al11:Cr3:Ru2, thermodynamic database 104 Pt-Au, colloids; particles, electronic structure; phases 63 Pt-Co, microsegregation 19 Pt-5% Co, hardness; jewellery 102 Pt-5% Cu, hardness; jewellery 78, 102 Pt-5% Ir, Pt-5% Pd, hardness 102 Pt-Ru, microsegregation 19 Pt-5% Ru, hardness; jewellery 102 950 Pt-Ru, for findings; investment cast ring 199 PtRuAl, oxidation, a 46 solders 199 superalloys, thermodynamic database 104, 189 welding, Pt-5% Cu, -5% Ru, -3% V, for jewellery 23

Palladium, activation layers, by CVD, a 96 boiling point, melting point 130 layer, on poly(p-xylylene), a 209 membranes 96, 136, 157, 209 nanoparticles 3, 36, 69, 83, 157, 172, 209 nanowires, a 98 Pd, Pd-Au films, CO adsorption, a 95 Pd/C SWNTs, ohmic contacts, a 98 Pd-polyaniline composite materials 3 refining 68 Rh (first film)/Pd bilayer, H2, NH3 sensing 204 in sensors 204 Tammann temperature 162 thick films, H2 sensing 204 thin films, H-induced stress relaxation, a 95 structured surfaces, SERS, a 208 vapour pressure equation, vapour pressure value 130 Palladium Alloys, Au-Pd, diffusion bonding 19 Au-Pd white, for findings 199 casting, for jewellery 19 CoPd thin films, electrodeposition, magnetism, a 157 dental, hardening, a 211 FePd, martensitic transformation, a 46 jewellery 19, 199 membranes: Pd-Ag, tubular; Pd-Cu, foil 136 950 Pd, for findings, jewellery 199 Pd-Cu, Pd-Ga, Pd-Ru 19 Pt-5% Pd, hardness 102 solders 199 TiPd, + Hf, shape memory effect, a 208 ‘TruPd’, for jewellery 19 welding, for jewellery 199 Palladium Complexes, medicine 36 nanoscale bowl-shaped hexa-Pd cage, self-assembly, a 156 Pd carbenes, as catalysts, a 210 Pd dithiocarbamates, for CVD, a 47 Pd(hfac)2, CVD precursor, a 96 Pd(II) + N-ally-N'-pyrimidin-2-ylthiourea, a 208 photoconversion 36 pyrazole-based allyl-Pd, liquid crystal behaviour, a 46 supramolecular architecture, a 46 solvent-free synthesis, a 156 Palladium Compounds, FePd thin films, magnetism, a 95 Mg–(Ir,Rh,Pd)–Si, H sorption, a 95 PdCl2, Pd(NO3)2, + polyaniline 3 PdCl2, skin patch tests 19 Pd perovskites, preparation; autocatalysts; catalysts 87 Pd sulfide thin films, by aerosol-assisted CVD, a 47 PdS, by direct sulfuration of Pd layers, a 156 Patents 50–51, 99–101, 159–161, 212–214


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Platinum Complexes, cyclometallated Pt(II)/SBA-15, a 47 medicine 36 OLEDs 85, 96 208 cis-(PEt3)2Pt(OTf)2 + 1,1,1-tris(4-pyridyl)COOR, a photoconversion 36 platinacycles, by RCM 127 [PtCl2(COD)], precursor, for PtL2R2, PtL'R2 127 cis-[PtCl2(PPh3)2], solvent-free synthesis, a 156 2– 2+ [PtCl6] , [Pt(NH3)4] , as catalyst precursor 42 [Pt(CO3)(PPh3)2], solvent-free synthesis, a 156 Pt(II) double square cage, a 208 [PtI2(CO)]2, promoter, in Ir-catalysed carbonylation, a 97 Pt(II) + N-ally-N' -pyrimidin-2-ylthiourea, a 208 [Pt(OH)2Me2(dpa)], self-assembly, a 156 [Pt2(μ-OH)2Me4(dpa)2][B(OH)(C6F5)3]2, a 156 tetra-Pt square, self-assembly, a 156 Platinum Compounds, H2PtCl6, + TiO2, a 156 βNdPt, NdPt2, a 46 PtCl2, + solid phosphines, reaction, a 156 [Pt(NH3)4](HCO3)2 fibres, as templates, a 46 Pt perovskites, preparation 87 Poisoning, catalysts 162 Polymerisation, by metathesis 69 Polymers, diene based, hydrogenation 16 Pd-polyaniline, Pd-polyaniline derivatives 3 polystyrene, selective hydrogenation, aromatic rings, a 48 poly(p-xylylene), Pd layer, a 209 synthesis, by ROMP 69 Propane, dehydrogenation, a 48 Propionic Acid, vapour, sensor, a 96 Propylene, hydroformylation 116, 164 PVD, Pd, Pd-Au, Pt, Pt-Au films, a 95

Ruthenium, (cont.) refining 68 Tammann temperature 162 vapour pressure equation, vapour pressure value 130 Ruthenium Alloys, Pd-Ru, for jewellery 19 104 Pt84:Al11:Cr3:Ru2, thermodynamic database Pt-Ru, microsegregation 19 Pt-5% Ru, hardness; jewellery 102 950 Pt-Ru, for findings; investment cast ring 199 PtRuAl, RuAl, oxidation, a 46 single crystal superalloys, oxidation, a 156 Ruthenium Complexes, in biology 36 as catalyst precursors 42 luminescence, a 96, 209 medicine 36 OLEDs, a 96 photoconversion 36 photosensitiser, a 47 Ru(bpy)32+ system, decomposition of NH3, a 47 RuHCl(CO)L3 precursor, to tricarbido complexes 127 Ru macrocycle, corrosion inhibitor, for steel, a 95 solar cells, a 47 Ruthenium Compounds, Ru perovskites, preparation 87 RuIn3, semiconductor, a 156 RuO2 thick film resistors, a 49 RuO2/4H-SiC Schottky diodes, a 49

Radiometer, using thin film Pt thermometers, a 96 RCM, formation, iridacycles, platinacycles 127 Reactors 83, 98, 136 Reduction, alkenes, alkynes, arenes, benzene, CO2, heteroaromatics 16 C-C double bonds, in synthesis 172 with hydride, Pt-Cu/C 138 imine 83 ketones 172 nitrate, a 210 NO, by propene 63 NOx 157, 162, 185 O 27, 63, 98, 211 Rh/CeO2, a 158 Refining, precious metals 68 Reforming 27, 34, 63, 158, 185 Relativistic Effects, Pd, eka-Pt, Pt 63 Resistors, thick film, RuO2, a 49 Rhodium, boiling point, melting point 130 refining 68 204 Rh (first film)/Pd bilayer, H2, NH3 sensing Tammann temperature 162 vapour pressure equation, vapour pressure value 130 Rhodium Complexes, [Cp*RhCl2]2, to di-alkenyl-Rh 127 Cp*RhLCl2 precursors, to Cp*RhL{(CH2)n} 127 dirhodium tetracarboxylates, anticancer, a 211 medicine 36 [Rh2(bza)4(pyz)]n, gas adsorbency, a 95 Rh(II) tetramesitylporphyrin, Rh(III) porphyrin alkyls, a 95 Rh(I) + tris(hydroxymethyl)phosphine, H2O-soluble, a 208 Wilkinson’s catalyst 116, 150 Rhodium Compounds, Mg–(Ir,Rh,Pd)–Si, H sorption, a 95 Ring-Closing Metathesis, in synthesis 69 ROMP, in synthesis 69 Rubber, nitrile, hydrogenation, a 210 Ruthenium, Al-Cr-Ru, Cr-Ru 104 boiling point, melting point 130 nanoparticles 36, 97 phase diagrams 104, 189 Pt-Al-Cr-Ru, thermodynamic database 104 Pt-Al-Ru, liquidus surface projections 104 Pt-Cr-Ru, isothermal section; liquidus surface 189


Schottky Diodes, RuO2/4H-SiC, a 49 Semiconductors, RuIn3, a 156 Sensors, glucose, a 96, 97, 209 H2 204 MeOH 3 NH3 204 propionic acid vapour, a 96 Shape Memory Effect, TiPd, + Hf impurities, a 208 Single Crystals, Ir, deformation, a 208 Ru superalloys, a 156 RuIn3, a 156 Solar Cells, a 47 Solders, Pd, Pt 199 Sonogashira Couplings 87, 127 Soot, diesel, oxidation, a 48 Sputtering, magnetron, for preparing Pt/C catalysts 42 Sugars, reducing, selective oxidation 63 Sulfur, compounds, catalyst posion 162 Sulfur Oxides, SO2, adsorption, by [Rh2(bza)4(pyz)]n, a 95 Superalloys, Pt-based, thermodynamic database 104, 189 single crystal, Ru, oxidation, a 156 Suzuki Couplings 83, 87, 127, 209, 210 Suzuki-Miyaura Couplings, a 48 Tammann Temperature, Ir, Os, Rh, Ru, Pd, Pt 162 Tetralin, amino-, synthesis 172 Thermodynamic Database, Pt-based superalloys 104, 189 Thermometers, Pt thin films, a 96 204 Thick Films, Pd, H2 sensing RuO2 resistors, a 49 Thin Films, Co/Pt, CoCr/Pt, CoCrPtTa 93 CoPd, magnetism, a 157 FePd, FePt, magnetism, a 95 Pd, H-induced stress relaxation, a 95 structured surfaces, SERS, a 208 Pd sulfide, a 47, 156 Pt, structured surfaces, SERS, a 208 as thermometers, a 96 Pt–diamondlike C nanocomposite, electrochemistry, a 156 Ti/Pt, electrical resistivity, a 46 Three-Way Catalysts 145, 162 Toluene, combustion 42 Vapour Pressure, equations, values, pgms

130

Water, dissolved O2, hydrogenation, a Water Gas Shift Reaction, Pd membrane reactors Welding, fusion, laser, spot, Pt jewellery alloys

209 136 23

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Platinum Metals Review Johnson Matthey Plc, Precious Metals Marketing, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K. E-mail: [email protected] http://www.platinummetalsreview.com/