Investigation of methanol mobility in zeolite H-ZSM-5 pores as a function of acid site density

Zeolites are porous aluminosilicate minerals widely used as adsorbents or catalysts in a myriad of commercial petrochemical and environmental processes including production of transportation fuels (such as gasoline) and exhaust after-treatment of an end-pipe of a mobile (car or truck) or stationary source (industrial chimney). The process involves the diffusion of molecules through the zeolite pores to and from the active sites, which are often Brønsted acidic sites. The diffusion characteristics of the reactants and products determine the reaction kinetics of a reaction. The present study aims to understand the diffusion properties of methanol as a function of Brønsted acidic site density of zeolite H-ZSM-5, which is the part of methanol to gasoline (MTG) process. This information enables us to better understand and tune the MTG activity, product selectivity and catalyst stability.

沸石（zeolites）是一类多孔铝硅酸盐矿物，被广泛用作吸附剂与催化剂，应用于众多商用石油化工及环境治理过程中，涵盖运输燃料（如汽油）的生产，以及移动源（汽车、卡车）或固定源（工业烟囱）末端排气管道的后处理工序。此类过程涉及分子在沸石孔道内往返活性位点的扩散行为，此类活性位点多为布仑斯惕酸性位点（Brønsted acidic sites）。反应物与产物的扩散特性直接决定反应的动力学行为。本研究旨在探究甲醇的扩散特性随沸石H-ZSM-5的布仑斯惕酸性位点密度的变化规律，而沸石H-ZSM-5是甲醇制汽油（methanol to gasoline，简称MTG）工艺所使用的核心催化材料。该研究结果可帮助我们更好地理解并调控MTG工艺的催化活性、产物选择性与催化剂稳定性。