Experimental and kinetic investigation of 1,2,4-trimethylbenzene oxidation at low temperature

Abstract The oxidation of 1,2,4-trimethylbenzene (TMB124) for equivalence ratio of 2.0 was studied in a Jet-stirred reactor over the temperature range of 700–1100 K at atmospheric pressure. Mole fraction profiles of 22 species, including reactants, intermediates, and products were identified by on-line GC analysis. Based on the measurements and theoretical calculations, a detailed chemical kinetic model involving 544 species and 3248 reactions was established. Rate constants of TMB124 decomposition, reaction with HO 2 , ipso-additions and metatheses with abstraction of methyl H-atom were updated. New pathways of H-abstraction from the 1- and 2-methyl groups were considered. The final model leads to an overall satisfactory agreement between the experimental observations and predictions for the major species and intermediates. Rate-of-production analysis indicates that the TMB124 consumption is dominated by metatheses giving three dimethyl benzyl radicals. From the sensitivity analysis, it is obvious that the reactions of HO 2 radical and the three dimethyl benzyl radicals have promoting effect, while the H-abstraction reactions of TMB124 exhibit strong inhibiting effect. These results will enrich the understanding of low temperature chemistry of TMB124 and facilitate to further model development and validation.