Oxidation, ignition and combustion of toluene: Experimental and detailed chemical kinetic modeling

The oxidation of toluene was studied in a jet-stirred reactor at 1 atm. New experimental results were obtained over the high temperature range 1000–1375 K, and variable equivalence ratio (0.5 ⩽ φ ⩽ 1.5). Concentration profiles of reactants, stable intermediates and final products were measured by probe sampling followed by on-line and off-line GC analyses. These experiments were modeled using a detailed kinetic reaction mechanism (120 species and 920 reactions, most of them reversible). This kinetic scheme was also used to simulate the ignition of toluene–oxygen–argon mixtures and the burning velocities of toluene–air mixtures. The presently proposed mechanism has already been validated by simulating the oxidation of benzene at 0.46 to 10 atm under stirred-reactor conditions, the ignition of benzene–oxygen–argon mixtures and the combustion of benzene in flames. Sensitivity analyses and reaction path analyses, based on species rates of reaction, were used to interpret the results. The routes involved in toluene oxidation have been delineated: toluene oxidation proceeds via the formation of benzyl, by H-atom abstraction, and the formation of benzene, by H-atom displacement yielding methyl and benzene; benzyl oxidation yields benzaldehyde, that further reacts yielding phenyl whereas benzyl thermal decomposition yields acetylene and cyclopentadienyl; further reactions of cyclopentadienyl yield vinylacetylene.