The oxidative dimerization of CH4 to C2H4 and C2H6 over MgO and CaO is strongly influenced by certain group IA ions which are employed as promoters. Lithium is an effective promoter for MgO, but sodium and potassium are not; all three group IA ions are effective promoters for CaO. Centers of the type [M'O-] (M' is a substitutional group IA ion) are present in each active and selective catalyst, which supports the hypothesis that these centers are active for the formation of CH3' radicals and, therefore, in the overall oxidative dimerization reaction.
關聯:
Journal of the American Chemical Society, 109(16): 4808-4810