(600c) How Charge Screening Affects Zeolite-Catalyzed C-C Coupling Reactions

Wang, B., The University of Oklahoma
Zeolites are remarkable materials with adjustable confinement and Brønsted acid strength that catalyze reactions of vital importance. An issue that has attracted the attention of researchers for a long time is the role that the zeolite characteristics, such as intrinsic acid strength, structural confinement, as well as van der Waals and Coulomb interactions between the molecules and the zeolite framework, may have on the catalytic phenomena. In this study, we focus on the important influence of the charge screening effect in zeolite catalysis using acylation of biomass-derived furanic compounds as an example. Insight into the transition state obtained from first-principles density functional theory and hybrid functional calculations demonstrates the importance of the ability of aromatics in the proximity to stabilize the acylium ion by charge delocalization, which lowers the activation barrier in the C-C coupling step. This charge screening effect may be generally true for other zeolite-catalyzed C-C coupling reactions that involves a charged species in the reaction pathway.