The role of carbon-carbon phenyl migration in the pyrolysis mechanism of beta-O-4 lignin model compounds: phenethyl phenyl ether and alpha-hydroxy phenethyl phenyl ether

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Journal of Physical Chemistry A

DOI:https://doi.org/10.1021/jp3104694· OSTI ID:1060842

Beste, Ariana ^[1]; Buchanan, III, A C ^[1]

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1. ORNL

We investigate phenyl shift and subsequent beta-scission reactions for PhCHXCHOPh [X = H, OH], which are part of the pyrolysis mechanism of phenethyl phenyl ether (PPE) and alpha-hydroxy PPE. PPE and its derivatives are model compounds for the most common linkage in lignin, the beta-O-4 linkage. We use density functional theory to locate transition states and equilibrium structures, and kinetic Monte Carlo in combination with transition state theory for kinetic simulations. Oxygen-carbon and carbon-carbon phenyl shift reactions proceed through cyclic intermediates with similar barriers. But, while subsequent beta-scission of the oxygen-carbon shift products proceeds with virtually no barrier, the activation energy for beta-scission of the carbon-carbon shift products exceeds 15 kcal/mol. We found that about 15 % of beta-radical conversion can be attributed to carbon-carbon shift for PPE and alpha-hydroxy PPE at 618 K. Whereas the oxygen-carbon shift reaction has been established as an integral part of the pyrolysis mechanism of PPE and its derivatives, participation of the carbon-carbon shift reaction has not been shown previously.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1060842
• Journal Information: Journal of Physical Chemistry A, Vol. 116, Issue 50; ISSN 1089--5639
• Country of Publication: United States
• Language: English