CATALYTIC LOW-TEMPERATURE OXYDEHYDROGENATION OF METHANE TO HIGHER HYDROCARBONS WITH VERY HIGH SELECTIVITY AT 8-12-PERCENT CONVERSION

Oxydehydrogenative coupling of methane to higher hydrocarbons has been obtained with close to 100% selectivity at 600-degrees-C and atmospheric pressure in the presence of steam over a CaNiK oxide catalyst. The reaction resulting in higher hydrocarbons is catalytic. Some carbon dioxide is produced thermally. The reaction is slightly exothermic. An Arrhenius plot shows that methane oxidation to carbon dioxide predominates at temperatures above 600-degrees-C and oxydehydrogenation of methane is dominant at lower temperatures. Artifacts, such as carbonate formation on the catalyst, have been excluded. The importance of exact catalyst composition and activation and the effect of the composition of the feed are demonstrated. A mechanism of catalyst deactivation is proposed.