Mesoporous ZSM-5 Zeolites in Acid Catalysis: Top-Down vs. Bottom-Up Approach

Abstract

<p>A top-down desilication of Al-rich ZSM-5 zeolites and a bottom-up mesopores creating method were evaluated in this study. Three liquid–solid and one gas–solid heterogeneously-catalysed reactions were chosen to establish relationships between zeolites textural properties and their catalytic behavior in acid-catalysed model reactions that are influenced by shape selectivity: Diels-Alder cyclization between isoprene and methylacrylate, Methanol-to-Olefins (MTO) reaction, chlorination of iodobenzene with trichloroisocyanuric acid (TCCA), and Friedel-Crafts acylation of anisole by carboxylic acids with differing sizes. It is found amongst others that no optimal mesoporosity for all the different reactions can be easily obtained, but depending on the chosen application, a specific treatment has to be set to achieve high activity/selectivity and stability.</p>