A detailed kinetic study on oxidation of benzyl alcohol

Abstract

The atmospheric oxidation of benzyl alcohol (A1CH2OH) has been investigated in a jet-stirred reactor (JSR) at equivalence ratios of 0.4 and 2.0 within 700–1100 K. Mole fraction profiles of 19 species were analyzed by online GC and GC/MS techniques. Rate constants of the unimolecular decomposition of A1CH2OH to benzyl and OH, bimolecular reaction with O2, H-abstractions by OH, H and HO2 as well as ipso-addition reactions with CH3 and OH radicals were calculated. H-abstraction reactions of benzaldehyde (A1CHO) were also calculated. Based on the experimental observations and theoretical calculations, a detailed kinetic model involving 304 species and 1903 reactions was developed with reasonable prediction against the measured data. In general, the peak concentrations of hydrocarbons and aromatic species in the rich condition is relatively higher than those in the lean condition, while the oxygenated species exhibit the contrary tendencies. The temperatures of peak values of intermediates at lean condition are relatively lower than those at rich condition. Benzene is mainly produced via the ipso-addition of A1CH2OH. The rate-of-production analysis indicates that the consumption of A1CH2OH is dominated by H-abstraction reactions giving rise to A1CHOH, followed by the reaction sequence of A1CHOH→ A1CHO→ A1CO→ A1-→ A1OO→ A1O→ A1OH. The sensitivity analysis demonstrates that the decomposition of H2O2 to two OH radicals exhibits a strong promoting effect for the lean condition, while the H-abstraction of benzyl alcohol by OH radical producing A1CHOH and H2O exhibits a strong promoting effect for the rich condition. Reaction of A1OH and O2 producing A1O and HO2 presents a strong inhibiting effect at both conditions. Moreover, the benzene formation is at the same level in the oxidation of both A1CH2OH and anisole, suggesting that A1CH2OH could be potentially used as alternative fuels for engine applications.