Synthesis and Modification of Micro‐Mesoporous ZSM‐5/S‐1 Composite Zeolite and Its Catalytic Alkylation of Ethylbenzene with Ethanol

Current research and industrial production in conventional alkylation synthesis of p ‐diethylbenzene (PDEB) focus on simplifying processes, reducing costs, and improving single‐pass yield. Accordingly, developing catalysts combining high stability with exceptional selectivity has become a critical research priority. The micro‐mesoporous ZSM‐5/S‐1 (Z/S) composite zeolite was synthesized via a hydrothermal method, followed by systematic modification to develop tailored catalysts for the alkylation of ethylbenzene with ethanol to produce PDEB. To improve PDEB selectivity and yield, modifications with P, Si, La, and La‐Mg were applied to the H‐form Z/S composite zeolite, and their impacts on its properties and catalytic performance were studied. The results showed that under the optimized reaction conditions, the Z/S composite zeolite modified with 6% P 2 O 5 (Z/S‐6P) exhibited the best catalytic activity, affording a PDEB selectivity of 96.7% and a yield of 18.9%. The enhanced catalytic performance of Z/S‐6P catalyst in the ethylbenzene–ethanol alkylation could be related to synergistic effect of diffusion control, shape selectivity, and the well‐balanced distribution of Brønsted/Lewis acid regulation. This modified Z/S composite zeolite, characterized by a facile preparation procedure, high activity, and good stability, may have potential for application in the ethylbenzene–ethanol alkylation process.