Ab initio enhanced sampling kinetic study on MTO ethene methylation reaction

The methylation reaction of ethene with methanol over the Bronsted acidic ZSM-5 catalyst is one of the prototype reactions within zeolite catalysis for which experimental kinetic data is available. It is one of the premier reactions within the methanol-to-olefins process and has been the subject of extensive theoretical testing to predict the reaction rates. Herein, we apply, for the first time, first principle molecular dynamics methods to determine the intrinsic reaction kinetics taking into account the full configurational entropy. As chemical reactions are rare events, enhanced sampling methods are necessary to obtain sufficient sampling of the configurational space at the activated region. A plethora of methods is available which depend on specific choices like the selection of collective variables along which the dynamics is enhanced. Herein, a thorough first principle molecular dynamics study is presented to determine the reaction kinetics via various enhanced MD techniques on an exemplary reaction within zeolite catalysis for which reference theoretical and experimental data are available. (C) 2020 Elsevier Inc. All rights reserved.