The use of carbon catalysts and of nitrous oxide in promoting the conversion of methane

Abstract This paper reports on the coupling of methane to C 2 and higher hydrocarbons over a carbon catalyst in the absence and presence of nitrous oxide and a lithium-promoted carbon catalyst in the absence and presence of nitrous oxide. The kinetics of the methane conversion were studied in a flow system over the temperature range 700–1100°C. At 850°C the conversion of methane was increased by a factor of about 800 in the presence of the carbon catalyst. The selectivity to C 2 hydrocarbons was, however, low and the main products were hydrogen and carbon. The Li/carbon catalyst was similarly effective and led to a better selectivity for C 2 hydrocarbons. Nitrous oxide had a strong promoting effect on the homogeneous coupling of methane but a less noticeable effect in the presence of the catalysts. Nitrous oxide improved the selectivity to C 2 hydrocarbons. Under the conditions of the present experiments the carbon-lithium oxide catalyst is able to facilitate the oxidative coupling of methane to give 36% conversion with selectivity to C 2 hydrocarbons over 70%.