H-Abstraction from Methane in H-ZSM5 Zeolite

The interaction of methane with an extra-framework oxygen atom in acidic Zeolite (H-ZSM5) porous substrate has been investigated by means of Density Functional Theory plus Dispersion energy calculations and reaction path has been obtained exploiting Climbing Image Nudged Elastic Band method (c-NEB). Zeolite was modelled by its crystallographic structure subject to periodic boundary condition. Relaxation of the zeolite cage is fundamental for a correct energetics. The reaction path for the H - abstraction reaction of methane, in presence of an open shell oxygen atom within the zeolite along (010) straight channel leads to the formation of a slightly distorted H2O water molecule and CH3 radical. These in bulk calculations support the interesting idea that open shell systems, involving an extra cage Oxygen atom, favour the H-abstraction from small hydrocarbons.