Oxidative Conversion of Methane and C 2 Hydrocarbons on Oxides: Homogeneous versus Heterogeneous Processes

Abstract

A study of the reactions of methane, ethane and ethylene with oxygen in a quartz reactor, either empty of containing a lithium-magnesium oxide catalyst, was carried out to assess the relative importance of heterogeneous versus homogeneous processes in the oxidative convertion of these hydrocarbons. At low temperatures the oxidative dimerization of methane does not occur; only the catalytic total oxidation of hydrocarbons to carbon dioxide, which is probably a primary product , proceeds at a measurable rate. At high temperatures the dimerization proceeds catalytically into ethane, which is dehydrogenated to ethelyne. Ethylene is oxidized in the gas phase to carbon monoxide at 600 °C. The view according to which the surface is a source of radicals, the other steps occurring exclusively in the gas phase, is criticized.