PARTIAL ELECTROCHEMICAL OXIDATION OF METHANE UNDER MILD CONDITIONS

We have made a preliminary study of the partial oxidation of methane at 25-degrees-C in aqueous media. The reactions were performed by using gold, glassy carbon, Cu and Hg cathodes in an alkaline electrolyte containing dissolved O2. The main oxidation products under these new reaction conditions are formaldehyde and methanol. The rates of formaldehyde formation increased with cathodic current density. The CH2O formation rate at a Cu electrode at 50 mA cm-2 was 1.5 x 10(-3) mol cm-2 h-1 during the first 18 min of the reaction. The CH2O concentration oscillated with time, and CO and CO2 were usually minor reaction products. The oxygen species, long-lived O2-, is suggested to play a role in CH4 activation.