Mechanism of the formation of carbon oxides under conditions of the oxidative chlorination of methane: IV. Kinetics of the reaction of CCl4 with oxygen on copper-containing salt catalysts for methane oxychlorination at reduced partial pressures of Cl2 in the reaction mixture

The kinetics of the oxidative dechlorination of CCl4 on two supported salt catalysts for methane oxychlorination (CuCl2-KCl and CuCl2-KCl-LaCl3) in the presence of methane at 350–450°C was studied using a gradientless method. It was found that, at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ P_{Cl_2 } $$\end{document} > 0.15 kPa, the presence of methane in the reaction mixture had no effect on the kinetics of CCl4 oxidation but decreased the activation energy E to ∼22 kcal/mol. At \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ P_{Cl_2 } $$\end{document} < 0.15 kPa, the kinetic orders with respect to oxygen and chlorine changed and E decreased to ∼17 kcal/mol. The rate of formation of CO2 as a by-product of the reaction of methane oxychlorination was described by an exponential equation in combination with rate equations for the oxidation of other chloromethanes and methane. An equation consistent with the observed rate laws of this reaction in the presence of methane was derived from the previously proposed reaction scheme for the mechanism of the oxidative dechlorination of CCl4.