Diffusion of Trimethylbenzenes and Xylenes in Zeolites with 12- and 10-Ring Channels as Catalyst for Toluene-Trimethylbenzene Transalkylation

Abstract

A molecular dynamics study of the diffusion of trimethylbenzene (TMB) and xylene molecules involved in toluene and TMB transalkylation reaction has been performed over 6 different pure-silica zeolites, containing 10- and 12-ring channels: BOG, MSE, IWR, SFS, SOF, and UWY. The shape selective properties of these six frameworks have been tested using two different loadings: one loading characteristic of the early stage and another of the late stage of the reaction. The collected data explains the diffusion behavior of these molecules in the zeolite frameworks and allows researchers to obtain trends and also rationalize their performance as candidates for the selective production of p-xylene during transalkylation of toluene and TMB. UWY appears a promising zeolite that allows the reaction of the TMBs in the 12-ring channels, is able to host the transition states, and favors the preferential diffusion of p-xylene in the 10-ring channels.

Simulation-based evaluation of zeolite adsorbents for the removal of emerging contaminants

“…In the view of the widespread use of computational chemistry methods in zeolite science, 43,44 this appears somewhat surprising. In the field of molecular mechanics calculations, force-field based Monte Carlo (MC) and molecular dynamics (MD) simulations have been employed to study the adsorption and/or diffusion of organic molecules in all-silica zeolites for several species of considerable complexity, including substituted aromatics, [45][46][47][48][49][50][51] organic structure-directing agents (OSDAs), [52][53][54][55][56][57][58] and glucose. 59 In contrast to this, applications of force field methods to study the interaction of pharmaceuticals with zeolites are scarce, with the MD investigation of salbutamol and theophylline diffusion in zeolite beta by Fatouros et al being a rare example.…”

High‐Pressure Operando UV‐Vis Micro‐Spectroscopy of Coke Formation in Zeolite‐based Catalyst Extrudates during the Transalkylation of Aromatics

“…During the transalkylation process, toluene and 1,2,4‐TMB can undergo several different reactions under the influence of a solid acid catalyst. These reactions include transalkylation, dealkylation, disproportionation and isomerization reactions, forming a mixture of products, including benzene, m ‐xylene, p ‐xylene, o ‐xylene, 1,2,3‐TMB and 1,3,5‐TMB [28–30] . Which of these different reaction pathways take place, is largely dependent on the acidity of the zeolite that is employed.…”

Simulation-Based Evaluation of Zeolite Adsorbents for the Removal of Emerging Contaminants

“…In the view of the widespread use of computational chemistry methods in zeolite science, [43,44] this appears somewhat surprising. In the field of molecular mechanics calculations, force-field based Monte Carlo (MC) and molecular dynamics (MD) simulations have been employed to study the adsorption and/or diffusion of organic molecules in all-silica zeolites for several species of considerable complexity, including substituted aromatics, [45][46][47][48][49][50] organic structure-directing agents (OSDAs), [51][52][53][54][55][56][57] and glucose. [58] In contrast to this, applications of force field methods to study the interaction of pharmaceuticals with zeolites are scarce, with the MD investigation of salbutamol and theophylline diffusion in zeolite beta by Fatouros et al being a rare example.…”