Theoretical investigation of the methane activation reaction on protonated zeolite from generalized valence-bond plus configuration interaction calculations

Abstract

Generalized valence-bond plus configuration interaction calculations are performed to study the activation of methane by a protonated model zeolite. The resulting transition state exhibits carbenium-like ion character, with a positively charged methyl group and an almost neutral hydrogen molecule to be formed. The nature of the transition state is similar to that obtained with density functional theory (DFT), in spite of significant differences in the geometry of the optimized model clusters. The activation barrier for the dehydrogenation process was found to be 74.8 kcal mol-1, which compares well with the DFT value of 82.0 kcal mol-1.