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

This paper reports on the coupling of methane to C2 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 C2 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 C2 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 C2 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 C2 hydrocarbons over 70%.