The role of initiation in oxidative coupling of methane Original Research Article

A generalized kinetic model, which satisfactory describes the main kinetic features of the gas-phase oxidative coupling of methane over a wide range of pressures and temperatures, was used to investigate the influence of an additional generation of methyl radicals on the process. It was shown that the additional generation of methyl radicals sufficiently enhances the yield of C2 hydrocarbons up to the values obtained with the use of catalysts, but even with a very high rate of additional generation of radicals by means of an effective reaction CH4+O2→CH3+HO2, subsequent gas-phase reactions do not permit to overcome a certain kinetic limit in C2 yield. This is very similar to the results obtained in the catalytic oxidative coupling of methane and it is in good agreement with the assumption that at atmospheric and elevated pressures the main role of most catalysts in this process is an additional generation of methyl radicals.