Fast hydrothermal synthesis of hierarchical Sn-Beta zeolite with high Sn content in fluoride media

Abstract

Abstract The incorporation of tetravalent Sn species into the framework of BEA zeolite possesses Lewis acidic property and thus exhibits prominent catalytic performances in several reactions. Unfortunately, the Sn-Beta zeolite obtained by hydrothermal synthesis method suffered from several drawbacks including long crystallization time, limited framework Sn content and large crystal size. To solve the problems, a hierarchical Sn-Beta zeolite was synthesized by an innovative hydrothermal method. A hollow mesoporous Sn–Si oxide produced by a simple aerosol process was used as the precursor. The crystallization was preformed in an extremely dense system for only 2–4 days. More Sn species from the precursor can be incorporated into the Beta zeolite as the framework Sn species, which benefits from the unique structure of the precursor. Moreover, the diffusion property is improved due to the formation of the mesopores. The obtained hierarchical Sn-Beta zeolite catalyst exhibits enhanced catalytic performance in the Baeyer–Villiger oxidation of bulky ketone.