Synthesis of Hierarchically Supported TS-2 Zeolites and Catalytic Application in the Epoxidation of Allyl Chloride

Construction of hierarchical pore structure in supported titanium silicalites was an effective strategy to enhance catalytic performance and avoid the separation process in industrial applications. Herein, the hierarchical TS-2 zeolites were successfully prepared on the TiO₂-modified α-Al₂O₃ pellets by "bottom-up" method, which had good and stable catalytic performance for the allyl chloride epoxidation. TritonX-100 could construct a mesopore structure, restrain nucleation, and affect titanium coordination of the zeolites, which was beneficial for preparing large size, much hexa-coordination titanium content, and hierarchically supported TS-2 zeolites in this work. Besides, the TiO₂-modified layer greatly increased the density and surface reactivity of hydroxyl groups on the α-Al₂O₃ pellet, which were well-situated to prepare homogeneous and anatase-free hierarchical TS-2 zeolite layers. The hierarchically supported TS-2 zeolites were applied to the epoxidation of allyl chloride with hydrogen peroxide, and allyl chloride conversion and epichlorohydrin selectivity were up to 99.13% and 96.53%, respectively.