Quantum chemical study of the thermal decomposition of o-quinone methide (6-methylene-2,4-cyclohexadien-1-one)

Abstract

o-Quinone methide (o-QM), or 6-methylene-2,4-cyclohexadiene-1-one, has been identified as an important intermediate in lignin and alkyl benzene combustion, and the thermal decomposition of o-QM is therefore relevant to the combustion of transportation fuels (which contain toluene) and of biomass and low-rank coals (which contain lignin). We present a comprehensive reaction mechanism for the unimolecular conversion of o-QM to the reaction intermediates tropone and fulvene, calculated using theoretical quantum chemical techniques. Enthalpies of formation for all reactants, products, and intermediates are calculated using the CBS-QB3 theoretical method. Transition states are determined with the..