Effect of ZSM-5 zeolite structure on the reaction performance of benzene alkylation: a computational study

This paper uses ZSM−5 zeolite to catalyze the alkylation of benzene and ethylene as a system to establish and verify a three−dimensional anisotropic diffusion−reaction mathematical model. This model takes into account the influence of zeolite morphology，pore structure and diffusion anisotropy. The simulation results show that changing zeolite particle shape would not significantly affect the apparent activity when the zeolite particle volume and sizes in a−, b−, and c−axis keep unchanged, indicating modifying zeolite particle shape is unnecessary in this case. When the particle volume remains constant, only shortening the size in b−axis could importantly reduce diffusion resistance and then enhance apparent catalytic activity, indicating that decreasing the size in b−axis is most favorable for diffusion and reaction in the preparation of ZSM−5 zeolites. When the particle size is 4 μm and the large pore diameter is 300 nm, the optimal large pore porosity that balances diffusion resistance and active material content is 0.16, corresponding to a maximum apparent reaction rate of 80.5 mol∕(m3·s). Besides, due to the influence of diffusion anisotropy, introducing the macropores being parallel to c−axis is most favorable. These results provide some theoretical guidance for the optimal design of ZSM−5 zeolite catalysts for benzene alkylation with ethylene and other zeolite catalysts. © 2024 Materials China. All rights reserved.