Experiments using gas mixtures of O2, C2H6 or C2H4 and CH4 or He have been carried out with a Li/MgO catalyst using a well-mixed reaction system which show that the total oxidation products, CO and CO2, are formed predominantly from ethylene, formed in the oxidative coupling of methane. It is therefore concluded that the network of reactions taking place during oxidative coupling of methane over a Li-doped MgO catalyst can be simplified to a serial reaction scheme: CH4→C2H6→C2H4→COx. Additional experiments have shown that the rates of gas-phase oxidation reaction of C2H6 and C2H4 are lowered by the presence of excess CH4 or by alkali metal carbonates.
Roos, J. A., Korf, S. J., Veehof, R. H. J., van Ommen, J. G., & Ross, J. R. H. (1989). Reaction path of the oxidative coupling of methane over a lithium-doped magnesium oxide catalyst : Factors affecting the Rate of Total Oxidation of Ethane and Ethylene. Applied catalysis, 52(1), 147-156. https://doi.org/10.1016/S0166-9834(00)83378-3