Preparation of KAlCl4/γ-Al2O3@ZSM-5 Core-Shell Complex Salt Catalyst and Its Disproportionation Reaction Study

The carrier γ-Al2O3@ZSM-5 was synthesized through the in situ growth of ZSM-5 on the surface of γ-Al2O3 crystals via hydrothermal synthesis. Subsequently, the complex salt KAlCl4 was impregnated onto γ-Al2O3@ZSM-5 at high temperatures to form the KAlCl4/γ-Al2O3@ZSM-5 core-shell complex salt catalyst. This catalyst was utilized for catalyzing the production of dimethyldichlorosilane, achieving optimal catalytic performance with a 70.68% yield of dimethyldichlorosilane under specific conditions: 10 wt % loading ratio of KAlCl4 complex salt, K/Al molar ratio of 1 : 2, 3 h impregnation time of AlCl3, and 0.7 g catalyst dosage. The reactants were mixed at a volumetric ratio of 1 : 2 and reacted at 200°C. Characterization techniques including XRD, XPS, FT-IR, BET, TGA, SEM, TEM, and Py-IR revealed that the KAlCl4/γ-Al2O3@ZSM-5 catalyst possessed a well-defined structure with a specific surface area of 176.2 m2/g and an average pore diameter of 15 nm, indicating it as a mesoporous material with excellent thermal stability. In the disproportionation reaction, the Lewis acid center was identified as the primary catalytic site.