A combined theoretical-experimental investigation on the mechanism of lignin pyrolysis: Role of heating rates and residence times Journal of Analytical and Applied Pyrolysis 128 (2017) 208–216 A. Galano1, J. Aburto2, J. Sadhukhan3, E. Torres-García2,3 1 Departamento de Química. Universidad Autónoma Metropolitana-Iztapalapa. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa. C. P. 09340. México D. F. México. 2
Biomass Conversion Management, Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas Norte # 152, C.P. 07730, México City, México. 3
Centre for Environment & Sustainability, University of Surrey, Guildford, Surrey, United Kingdom.
Supplementary Information
Scheme 1S. Common linkages in lignin.
Scheme 2S. Models used to mimic the β-O-4 linkage.
Scheme 3S. Different homolysis routes for model D proposed (Stage II, lignin thermal
decomposition,
corresponding
to
experimental measurements
between 200 and 350 °C). The Gibbs free energy of each step (ΔG) is provided next to the products, indicating the conversion, and are expressed in kJ/mol.
Table 3S. Gibbs free energies (kJ mol-1) of reaction for the homolysis of the βO-4 linkage in lignin. C-Cα
Cα-Cβ
Cβ-O
O-C
A
364.3
232.0
184.8
348.9
B
333.4
222.1
169.2
333.8
C D
341.8 335.4
219.4 217.1
183.3 178.0
344.8 341.2
E
348.7
183.9
137.6
341.4
Scheme 4S. Dehydration routes from model D (Stage II, lignin thermal decomposition). The Gibbs free energy of each step (ΔG) is provided below the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 5S. Different homolysis routes for intermediate E (Stage II, formation of most likely products by cracking of β-O-4 linkages and release of aromatic fragments). The Gibbs free energy of each step (ΔG) is provided next to the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 6S. Different routes for the thermal decomposition of intermediates E1 and E2. G values in kJ mol-1 (Stage III, lignin secondary pyrolysis). The Gibbs free energy of each step (ΔG) is provided below the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 7S. Different routes for the decomposition of intermediates E3 and E4 (Stage III, lignin secondary pyrolysis). The Gibbs free energy of each step (ΔG) is provided next to the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 8S. Different routes for a first hydration step involving intermediate E5. G values in kJ mol-1 (secondary reactions between the aromatic moieties and water). The Gibbs free energy of each step (ΔG) is provided below the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 9S. Different routes for second hydration (secondary reactions which promote aromaticity loss). G values in kJ mol-1. The Gibbs free energy of each step (ΔG) is provided below the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 10S. Fragmentation routes for intermediate E7. The Gibbs free energy of each step (ΔG) is provided next to, or below the products, indicating the conversion, and are expressed in kJ/mol.
Scheme 11S. Fragmentation routes derived from the reactions with •CHO. The Gibbs free energy of each step (ΔG) is provided next to, or below the arrow, indicating the conversion, and are expressed in kJ/mol. ____________________________ DOI of original article: http://dx.doi.org/10.1016/j.jaap.2017.10.009 E. Torres-Garcia, Biomass Conversion Management, Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas Norte 152, C.P. 07730, México City, México.
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