Oxidative Coupling of Methane on Sodium Aluminate- and Magnesium Oxide- supported Samarium Oxide

The oxidative coupling of methane was studied over basic and neutral oxides as well as supported Sm2O3 under various reaction conditions. Among the basic and neutral oxides investigated, NaAlO2 was found to be one of the most active and selective catalyst for C-2 hydrocarbon (ethane and ethylene) production at reaction temperatures higher than 750 degrees C; methane conversion is 13.4% and C-2 selectivity is 63% at 800 degrees C. These values compare favourably with those obtained from pure Sm2O3 under the same reaction conditions. On the Sm2O3 /MgO catalysts, a maximum percentage loading was observed for optimum total C-2 selectivity (25% Sm2O3 on MgO) the activity of which is comparable with that of pure Sm2O3 (calcined at 800 degrees C). Sm2O3/NaAlO2 catalysts also show loading dependence and, between 25-30% loading, the catalyst showed better activity and selectivity (> 750 degrees C) than pure Sm2O3. Product yields on both Sm2O3/MgO and Sm2O3/NaAlO2 catalysts were found to be stable at 815 degrees C for over 16 hours.