Discussion on the oxidative and the pyrolysis routes of the CH3 radicals in the partial oxidation of methane over La2O3

The mechanism of the partial oxidation of methane over lanthanum oxide La2O3 catalyst was investigated using a perfectly jet-stirred reactor. The proposed mechanism satisfactorily reproduces experimental findings over a large range of experimental parameters. The catalyst favors the production of methyl radicals. These radicals can follow the pyrolysis pathway leading to the C2 compounds or they can follow the oxidative pathway leading to the formation of formaldehyde, carbon monoxide and carbon dioxide. Both routes involve gas phase reactions and surface reactions. The mechanism shows that both routes are interconnected and that their relative importance depends on the operating conditions, that is temperature, residence time and catalyst amount. The mechanism is detailed step by step on the basis of flux and sensitivity analyses.