Dynamical observation of the catalytic activation of methanol in zeolites

The adsorption of methanol in the zeolites chabazite, ferrierite and silicalite has been studied using first principles molecular dynamics simulations. The study includes an investigation of the effect of both loading and temperature. At low coverage, methanol forms a hydrogen bonded complex in chabazite and silicalite but proton transfer appears to be stable in ferrierite when the methanol is in the eight-ring side channel. As the loading increases the methoxonium cation becomes the stable species and a surprisingly large weakening of the C–O bond occurs due to dynamical effects which may explain the enhanced susceptibility of the methanol to nucleophilic attack.