High pressure pyrolysis of toluene. 2. Modeling benzyl decomposition and formation of soot precursors

The pyrolysis of toluene, the simplest methyl-substituted aromatic molecule, has been studied behind reflected shock waves using a single pulse shock tube. Part 1 in this two-part series focused on the high-pressure experimental results and the high-pressure limiting rate coefficients for the primary steps in toluene decomposition. The present work focuses on the modeling of benzyl decomposition and the growth of key soot precursors (C2H2, C4H2, C8H6, and indene) from toluene pyrolysis with 81 among the 262 reactions in the detailed toluene model representing the chemistry that describes the formation and decomposition of these species. Feasible pathways for benzyl decomposition as well as phenylacetylene and indene formation have been tested. The simulations also show very good agreement with the single pulse shock tube profiles for the growth of key soot precursors such as C2H2, C4H2, C8H6, and indene.