Dr. Hunter's Class. Section 2 Notes - Page ... Chemistry 1506: Allied Health
Chemistry 2. Section 2: Alkenes .... Dr. Hunter's Class. Section 2 Notes - Page 11/
29.
Chemistry 1506
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Section 2 Notes - Page 1/29
Chemistry 1506: Allied Health Chemistry 2
Section 2: Alkenes, Alkynes, and Aromatic Compounds Hydrocarbons with Multiple Bonds
Outline
SECTION
2.1 INTRODUCTION AND NOMENCLATURE OF ALKENES.................................................2
SECTION
2.2 π-BONDS .......................................................................................................................................4
SECTION
2.3 PHYSICAL PROPERTIES .........................................................................................................5
SECTION
2.4 CHEMICAL PROPERTIES: ADDITION REACTIONS .......................................................6
SECTION
2.5 ADDITION POLYMERS ............................................................................................................8
SECTION
2.6 ALKYNES ...................................................................................................................................13
SECTION
2.7 AROMATIC HYDROCARBONS.............................................................................................17
SECTION
2.8 AMINO ACIDS HAVING SIMPLE AROMATIC SIDE CHAINS .......................................22
SECTION
2.9 AROMATIC REACTIONS .......................................................................................................23
SECTION
2.10 FUSED RING AROMATICS ..................................................................................................25
SECTION
2.11 HETEROCYCLICS (NOT COVERED IN DETAIL)...........................................................26
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Section
Dr. Hunter’s Class
Section 2 Notes - Page 2/29
2.1 Introduction and Nomenclature of Alkenes
Ethene = (Ethylene), CH2=CH2
IUPAC Rules Start numbering from the end that gives the double bond the lowest number. Indicate position of double bond(s) by numbers. Use the ene ending Indicated number of double bonds by prefixes (ene, diene, triene, tetraene, etc.) Examples
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 3/29
Geometric Isomers No free rotation (π-bonds) Experimental observations
cis isomers vs. trans isomers
Examples
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Section
Dr. Hunter’s Class
Section 2 Notes - Page 4/29
2.2 π-Bonds Bonding: sp2 hybridization for 3 σ-bonds to the three atoms bonded to each carbon pz orbital for π-bond Typical C=C bond distance (i.e., 1.34 Å) and thus shorter than the C-C distance (i.e., 1.54 Å) slightly shorter C-H distance than alkanes
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
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Dr. Hunter’s Class
Section 2 Notes - Page 5/29
2.3 Physical Properties Almost identical to Alkanes of same MW Van der Waals forces Slightly higher Mp and Bp Smell (turpentine like) Density Solubility
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Section
Dr. Hunter’s Class
Section 2 Notes - Page 6/29
2.4 Chemical Properties: Addition Reactions Addition reaction (generic) π-bonds weaker than σ-bonds
Hydrogenation: Addition of H2 or D2 (Pt catalyst)
Addition of Cl2 or Br2 (X2)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 7/29
Addition of HX ((HF) HCl, HBr (HI)) Halide Influences Markovnikov Addition
Addition of Water (Hydration) H+ Catalyst Markovnikov
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
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Dr. Hunter’s Class
Section 2 Notes - Page 8/29
2.5 Addition Polymers Definition of Addition Polymers No loss of mass Rapid chain growth π-bond opening “Generic” Synthesis Reaction typical monomers are CH2=CH-R
Role of Catalysts Speed reaction but aren’t themselves consumed Highly reactive species
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 9/29
Reversibility of Reactions Polymerization under low temperatures/high pressures i.e., monomer (liquids or gasses) -> polymer (solids)
Depolymerizations (unraveling) at high temperatures i.e., polymer -> monomer
Molecular Weights and Molecular Weight Distributions High average Molecular Weights Distributions rather than discrete weights
Linear Chains vs. Branched Chains
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 10/29
Examples Polyethylene, PE, Synthesis CH2=CH2, R = H
Poly(vinyl chloride), PVC, Synthesis CH2=CH-Cl, R = Cl
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 11/29
Polypropylene, PP, Synthesis CH2=CH-CH3, R = CH3
Polystyrene, PS, Synthesis CH2=CH-C6H5, R = C6H5
Poly(methyl methacrylate), PMMA, Synthesis CH2=C(CH3)(CO2CH3)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 12/29
Teflon Synthesis CF2=CF2
Rubber (Polyisoprene) Synthesis CH2=CH-CH=CH2
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
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Dr. Hunter’s Class
Section 2 Notes - Page 13/29
2.6 Alkynes Carbon-Carbon Triple Bonds sp hybridized Very Short C≡C Bond distance (i.e., 1.20 Å ), much shorter than the C=C distance (i.e., 1.34 Å) and the C-C distance (i.e., 1.54 Å) Bonding: 1 σ-bond and 2 π-bonds (px and py) slightly shorter C-H distance than alkanes or even alkanes Ethyne = Acetylene, H-C≡C-H
Physical Properties Almost identical to Alkanes/Alkenes of same MW Van der Waals forces Slightly higher Mp and Bp Density Solubility
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 14/29
Nomenclature yne ending yne > ene in priority of naming Examples
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 15/29
Alkyne Reactions Generic Reaction Very like Alkenes Normally Double Addition
Hydrogenation: Addition of H2 or D2 (Pt catalyst)
Addition of X2 (Cl2 or Br2)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 16/29
Addition of HX (most commonly HCl and HBr) Markovnikov Addition
Addition of H2O (H+ catalyst) Markovnikov Addition Secondary elimination of water from diol gives carbonyl group (aldehyde or ketone)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Section
Dr. Hunter’s Class
Section 2 Notes - Page 17/29
2.7 Aromatic Hydrocarbons Sources Coal Tar Coke production Direct separation Start of industrial chemistry Petroleum multiple processing steps Uses Octane enhancers in gasoline Plastics Pigments/Dyes Pharmaceuticals Aromatic:
Properties,
Reactivity,
Alkane/Alkenes/Alkynes)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
C/H
Ratios
(cf.
Chemistry 1506
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Section 2 Notes - Page 18/29
Substitution Reactions not Addition Reactions (i.e., not like alkenes)
Bonding / Resonance Stabilization
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 19/29
Nomenclature IUPAC Names Halobenzenes (X = F, Cl, Br, I)
Nitrobenzene (Z = NO2)
Alkylbenzenes (phenylalkanes)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 20/29
Common Names (IUPAC) Phenol (Z = OH)
Aniline (Z = NH2)
Toluene (Z = CH3, methylbenzene)
Benzoic Acid (Z = CO2H)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 21/29
Multiply Substituted Arenes Numbering Ring Positions
Ortho, Meta, Para, Ipso
As Side Chains (phenyl groups)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Section
Dr. Hunter’s Class
Section 2 Notes - Page 22/29
2.8 Amino Acids having Simple Aromatic Side Chains
Generic AA = H2N-CHR-CO2H
Phenyl Alanine (non-polar) R = CH2C6H5 PKU
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
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Dr. Hunter’s Class
Section 2 Notes - Page 23/29
2.9 Aromatic Reactions Substitution Reactions Require catalyst "Generic" Z+ Electrophiles
Nitration (Z = NO2, HNO3/H2SO4, TNT)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
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Section 2 Notes - Page 24/29
Sulfonation (Z = SO3H, H2SO4/SO3)
Halogenation (X = Cl or Br, Cl2/Fe or Br2/Fe)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
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Dr. Hunter’s Class
Section 2 Notes - Page 25/29
2.10 Fused Ring Aromatics Polycyclic Aromatic Hydrocarbons, PAHs Toxicity Naphthalene (C10H8)
Anthracene (C14H10)
Phenanthrene (C14H10)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Section
Dr. Hunter’s Class
Section 2 Notes - Page 26/29
2.11 Heterocyclics (Not covered in detail) Replace C-H by Heteroatom Groups such as: N, O, S, etc.
Important in Biomolecules
Pyridine (C5H5N)
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Section 2 Notes - Page 27/29
Index of Topics and Vocabulary 1.20 c ................................. 4, 13 1.34 c ................................. 4, 13 Acetylene ................................ 13 Addition .................................. 15 Addition of HX ......................... 7 Addition of Water ..................... 7 Addition Polymers .................... 8 Addition reaction....................... 6 Addition Reactions.................. 18 aldehyde .................................. 16 alkanes....................................... 4 alkenes..................................... 18 Alkenes.................................... 15 Alkylbenzenes ......................... 19 Alkyne Reactions .................... 15 Alkynes ................................... 13 Amino Acids having Simple Aromatic Side Chains .......... 22 Aniline..................................... 20 Anthracene .............................. 25 Arenes ..................................... 21 Aromatic.................................. 17 Aromatic Hydrocarbons .......... 17 Aromatic Reactions................. 23 Benzoic Acid........................... 20 Biomolecules........................... 26 Bonding......................... 4, 13, 18 Bp ........................................ 5, 13 Br2 ....................................... 6, 15 Br2/Fe ...................................... 24 Branched Chains ....................... 9 C≡C Bond distance ................. 13 C/H Ratios............................... 17
C=C bond distance ....................4 C=C distance ...........................13 C10H8 .......................................25 C14H10 ......................................25 C5H5N......................................26 Carbon-Carbon Triple Bonds ..13 carbonyl group.........................16 catalyst.....................................23 Catalysts ....................................8 C-C distance ........................4, 13 CF2=CF2 ..................................12 C-H distance ........................4, 13 CH2=C(CH3)(CO2CH3) ...........11 CH2=CH2 .............................2, 10 CH2=CH-C6H5 .........................11 CH2=CH-CH=CH2 ..................12 CH2=CH-CH3 ..........................11 CH2=CH-Cl .............................10 CH2=CH-R ................................8 chain growth ..............................8 Chemical Properties: Addition Reactions ................................6 cis isomers .................................3 Cl2 ........................................6, 15 Cl2/Fe.......................................24 Coal Tar...................................17 Coke.........................................17 Common Names ......................20 D2 .........................................6, 15 Density.................................5, 13 Depolymerizations.....................9 diene ..........................................2 diol...........................................16
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Double Addition...................... 15 Dyes ........................................ 17 Electrophiles............................ 23 ene ....................................... 2, 14 ene ending ................................. 2 Ethene........................................ 2 Ethylene .................................... 2 Ethyne ..................................... 13 free rotation ............................... 3 Fused Ring Aromatics............. 25 gasoline ................................... 17 Geometric Isomers .................... 3 H+ catalyst ............................... 16 H+ Catalyst ................................ 7 H2 ........................................ 6, 15 H2O.......................................... 16 H2SO4/SO3............................... 24 Halide Influences ...................... 7 Halobenzenes .......................... 19 Halogenation ........................... 24 HBr...................................... 7, 16 H-C≡C-H................................. 13 HCl ...................................... 7, 16 Heteroatom Groups ................. 26 Heterocyclics........................... 26 HF.............................................. 7 HI .............................................. 7 HNO3/H2SO4 ........................... 23 HX....................................... 7, 16 Hydration .................................. 7 Hydrogenation..................... 6, 15 industrial chemistry................. 17 Ipso.......................................... 21 IUPAC Names......................... 19
Section 2 Notes - Page 28/29
IUPAC Rules.............................2 ketone ......................................16 Linear Chains ............................9 Markovnikov .............................7 Markovnikov Addition ........7, 16 Meta.........................................21 methylbenzene.........................20 Molecular Weight Distributions 9 Molecular Weights ....................9 monomer....................................9 monomers ..................................8 Mp .......................................5, 13 Naphthalene.............................25 Nitration...................................23 Nitrobenzene ...........................19 Nomenclature ....................14, 19 Octane......................................17 Ortho........................................21 PAH .........................................25 Para..........................................21 PE ............................................10 Petroleum.................................17 Pharmaceuticals.......................17 Phenanthrene ...........................25 Phenol......................................20 Phenyl Alanine ........................22 phenyl groups ..........................21 phenylalkanes ..........................19 Physical Properties ..............5, 13 Pigments ..................................17 PKU .........................................22 Plastics.....................................17 PMMA.....................................11 Poly(methyl methacrylate) ......11
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University
Chemistry 1506
Dr. Hunter’s Class
Poly(vinyl chloride) ................ 10 Polycyclic Aromatic Hydrocarbons ....................... 25 Polyethylene............................ 10 Polyisoprene............................ 12 Polymerization .......................... 9 Polymers.................................... 8 Polypropylene ....................... See Polystyrene.............................. 11 PP .......................................... See Properties ................................ 17 PS ............................................ 11 Pt catalyst ............................ 6, 15 PVC......................................... 10 px ............................................. 13 py ............................................. 13 Pyridine ................................... 26 pz ............................................... 4 Resonance Stabilization .......... 18 Reversibility of Reactions ......... 9 Ring Positions ......................... 21 Rubber..................................... 12 Secondary elimination of water .............................................. 16
Section 2 Notes - Page 29/29
Smell..........................................5 Solubility .............................5, 13 sp hybridized ...........................13 sp2 hybridization........................4 Substitution Reactions .......18, 23 Sulfonation ..............................24 Teflon ......................................12 tetraene ......................................2 TNT .........................................23 Toluene....................................20 trans isomers..............................3 triene..........................................2 Van der Waals forces...........5, 13 X2 .........................................6, 15 yne ending ...............................14 Z+ .............................................23 π-bond .......................................4 π-bond opening..........................8 π-bonds................................3, 13 π-Bonds .....................................4 π-bonds weaker than σ-bonds ...6 σ-bond .....................................13 σ-bonds......................................4
2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University