Pyrolysis mechanism of carbon matrix precursor cyclohexane(V)-formation process of benzene from C4 species

Abstract Formation mechanism of important intermediate benzene of the pyrolysis process of carbon matrix precursor cyclohexane was studied theoretically. Thermodynamic parameters of five possible reaction paths (20 reaction steps) were computed by UB3LYP/6-31+G* method at different temperature ranges (298.15–1773.15 K) and different pressures (103.325, 2.67 kPa). The results show that (1) no matter what the initial species and reaction conditions are, the reaction paths that form benzene becomes the main reaction paths at certain temperature ranges, which means the reaction paths all contribute to the formation of benzene; (2) no matter what reaction pressures are, forming benzene from ·C 4 H 5 /·C 2 H 3 is the major reaction path, and then the reaction paths from ·C 4 H 3 /C 2 H 2 or ·C 4 H 5 /C 2 H 2 ; (3) lower reaction pressure has an inhibition effect on the reaction of stable mechanism, and more benefit in the formation of benzene.