Oxidative coupling of methane over samarium oxides using N2O as the oxidant

Abstract

Kinetic studies of the partial oxidation of CH₄ over Sm₂O₃ using N₂O and O₂ as oxidants have been carried out at 823–950 K and the kinetic features in the reactions with N₂O and O₂ have been compared. At a low temperature (823 K) and a pressure of the oxidants of 3–13 kPa, the oxidation by N₂O produced C₂H₆ with high selectivity, but only deep oxidation took place when O₂ was used as the oxidant. However, C₂H₆ was observable when the pressure of O₂ was lowered below 1kPa. The reactivity of O₂ was two orders of magnitude greater than that of N₂O. O₂ is a better oxidant than N₂O for the production of C₂ compounds. A reaction mechanism for the oxidation of CH₄with N₂O is proposed. Kinetic studies of the reaction have shown that N₂O decomposition is rate-determining. Kinetic studies of the oxidation with O₂ have confirmed the reaction mechanism proposed previously.