Exchange reaction of methane with deuterium over solid base catalysts

Abstract The exchange reaction of CH 4 with D 2 was carried out over 13 kinds of metal oxide catalysts. Among them, a series of alkaline earth metal oxides (MgO, CaO, SrO, and BaO) and La 2 O 3 exhibited activity at 300 °C. The variations of the activities of these catalysts as a function of the pretreatment temperature of the catalysts were measured. The pretreatment temperatures to give maximum activity were 700 °C for MgO and CaO prepared from Ca(OH) 2 , 800 °C for CaO prepared from CaCO 3 and for BaO, 1000 °C for SrO, and 650 °C for La 2 O 3 . The reaction rate of CH 4 + D 2 was higher than that of C 2 H 6 + D 2 and equal to that of CH 4 + CD 4 over alkaline earth metal oxides. In the exchange reaction of iso-C 4 H 10 with D 2 , a methyl H exchanged faster than a methyne H. It is suggested that the reaction of CH 4 + D 2 , as well as C 2 H 6 + D 2 and iso-C 4 H 10 + D 2 , is initiated by the abstraction of an H + by basic sites on the catalysts.