Pentaerythritol structure-directing agents bias aluminum siting in MFI zeolites to increase para-xylene selectivity during toluene methylation

IF 6.5 1区化学 Q2 CHEMISTRY, PHYSICAL

Journal of Catalysis Pub Date : 2025-10-07 DOI:10.1016/j.jcat.2025.116470

Andrew T. Norfleet, Sopuruchukwu Ezenwa, David Hibbitts, Rajamani Gounder

引用次数: 0

Abstract

MFI zeolites contain ten-membered ring channels (∼0.55 nm diameter) that intersect to form larger voids (∼0.70 nm diameter). The distribution of framework Al sites dictates the void environments that confine active H⁺ sites. MFI synthesized with pentaerythritol (PET) and Na⁺ as structure-directing agents are interrogated using kinetically controlled toluene methylation rates and xylene isomer selectivities. High para-xylene selectivity and low toluene methylation rates indicate that MFI-PET samples contain H⁺ sites predominantly in smaller channels. As-synthesized samples contain more framework Al than Na⁺, indicating that some charge compensation is provided by protonated PET-solvent complexes that bias Al siting towards smaller channels.

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季戊四醇结构导向剂在MFI沸石中偏置铝以增加甲苯甲基化过程中对二甲苯的选择性

MFI沸石含有十元环通道（~ 0.55 nm直径），它们相交形成更大的孔洞（~ 0.70 nm直径）。框架Al位点的分布决定了限制活性H+位点的空隙环境。用动力学控制的甲苯甲基化速率和二甲苯异构体选择性研究了以季戊四醇（PET）和Na+为结构导向剂合成的MFI。高对二甲苯选择性和低甲苯甲基化率表明MFI-PET样品中主要含有较小通道中的H+位点。合成的样品含有比Na+更多的框架Al，表明质子化pet溶剂配合物提供了一些电荷补偿，使Al偏向较小的通道。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Catalysis 工程技术-工程：化工

CiteScore

12.30

自引率

5.50%

发文量

447

审稿时长

31 days

期刊介绍： The Journal of Catalysis publishes scholarly articles on both heterogeneous and homogeneous catalysis, covering a wide range of chemical transformations. These include various types of catalysis, such as those mediated by photons, plasmons, and electrons. The focus of the studies is to understand the relationship between catalytic function and the underlying chemical properties of surfaces and metal complexes. The articles in the journal offer innovative concepts and explore the synthesis and kinetics of inorganic solids and homogeneous complexes. Furthermore, they discuss spectroscopic techniques for characterizing catalysts, investigate the interaction of probes and reacting species with catalysts, and employ theoretical methods. The research presented in the journal should have direct relevance to the field of catalytic processes, addressing either fundamental aspects or applications of catalysis.