Decomposition of methylbenzyl radicals in the pyrolysis and oxidation of xylenes

Abstract

Alkyl benzyl radicals are important initial products in thermal and combustion reactions of substituted aromatic fuels. The decomposition reactions of the three isomeric methylbenzyl radicals, formed as primary products in xylene combustion, are studied theoretically and are shown to be significantly more complex than previously reported. Thermochemical properties are calculated using the G3X and G3SX model chemistries, with isodesmic and atomization work reactions. G3X atomization calculations reproduce heats of formation for the 14 reference species in the work reactions to a mean unsigned error of 0.23 kcal mol-1, and maximum error of 0.70 kcal mol-1, slightly outperforming the G3SX metho..