Mechanism of pyrolysis of C2Cl6

Abstract

Using published data on the kinetics of pyrolysis of C₂Cl₆ and estimated rate parameters for all the involved radical reactions, a mechanism is proposed which accounts quantitatively for all the observations: equation image The steady‐state rate law valid for after about 0.1% reaction is equation image and the reaction is verified to proceed through the two parallel stages suggested earlier whose net reaction is equation image A reported induction period obtained from pressure measurements used to follow the rate is shown to be compatible with the endothermicity of reaction A, giving rise to a self‐cooling of the gaseous mixture and thus an overall pressure decrease.From the analysis, the bond dissociation energy DH⁰(C₂Cl₅Cl) is found to be 70.3 ± 1 kcal/mol and ΔH_f300⁰(·C₂Cl₅) = 7.7 ± 1 kcal/mol. The resulting πbond energy in C₂Cl₄ is 52.5 ± 1 kcal/mol.