Kinetics of the gas-phase thermal chlorination of methane

Based on information concerning the rate constants of elementary steps corrected with consideration for experimental data obtained under laboratory, pilot-plant, and industrial conditions, the kinetics of the gas-phase process of thermal chlorination of methane was considered. The form of the rate equation of the process depends on the mode of chain termination. Of four possible variants, cross termination with the participation of a chlorine atom and a hydrocarbon radical and quadratic-law termination on hydrocarbon radicals are significant under industrial conditions. The fractions of the participation of either of these variants at various degrees of chlorine conversion were determined. Rate equations were found to describe the chlorination of methane, methyl chloride, methylene chloride, and chloroform with cross and quadratic-law chain terminations. The overall kinetic order of these equations with respect to reactants was 1.5. Combined equations that imply the simultaneous occurrence of cross and quadratic-law chain terminations were proposed.