Complex Reaction Environments and Competing Reaction Mechanisms in Zeolite Catalysis: Insights from Advanced Molecular Dynamics

• Published in: Chemistry : a European journal Vol. 21; no. 26; pp. 9385 - 9396
• Main Authors: De Wispelaere, Kristof, Ensing, Bernd, Ghysels, An, Meijer, Evert Jan, Van Speybroeck, Veronique
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 22.06.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: ab initio calculations; Catalysis; Chemistry; Flexibility; Free energy; heterogeneous catalysis; Methyl alcohol; Molecular dynamics; olefins; Pathways; Surface chemistry; Zeolites; ab initio calculations; zeolites; heterogeneous catalysis; molecular dynamics; olefins
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201500473

The methanol‐to‐olefin process is a showcase example of complex zeolite‐catalyzed chemistry. At real operating conditions, many factors affect the reactivity, such as framework flexibility, adsorption of various guest molecules, and competitive reaction pathways. In this study, the strength of first principle molecular dynamics techniques to capture this complexity is shown by means of two case studies. Firstly, the adsorption behavior of methanol and water in H‐SAPO‐34 at 350 °C is investigated. Hereby an important degree of framework flexibility and proton mobility was observed. Secondly, the methylation of benzene by methanol through a competitive direct and stepwise pathway in the AFI topology was studied. Both case studies clearly show that a first‐principle molecular dynamics approach enables unprecedented insights into zeolite‐catalyzed reactions at the nanometer scale to be obtained. Unravelling zeolite catalysis: The potential and free energy surface of zeolite‐catalyzed reactions at real operating conditions can be complex. As such, techniques that allow sampling of larger portions of the potential and free energy landscape are required to obtain accurate information. By means of two case studies, the potential of advanced molecular dynamics simulations is demonstrated to study the complex and highly dynamical behavior within zeolite catalysis (see figure).