Gas-Solid Synthesis, Characterization And Catalytic Properties Of Sn-Beta Zeolite

In recent years, Sn-Beta zeolites as good Lewis acid catalysts opened up great applications especially for catalysis process. Therefore, developing new methods of preparing Sn-Beta zeolites and studying their catalytic properties are of great important significance.In this paper, Sn-Beta was prepared by gas-solid reaction using B-Beta as precursor. The B-Beta and resultant Sn-Beta zeolites were characterized by XRD, SEM, FT-IR, UV-Vis, MAS NMR, and the catalytic performance of Sn-Beta zeolite was investigated in the isomerization reaction of glucose into fructose. This paper mainly consists of three parts.B-Beta zeolites were synthesized in the mixed system of inorganic base and fluoride using TEAOH as the template agent, white carbon black as the silicon source and our own B-Beta zeolites as the seeds. The crystallization was carried out at423K for2-5days under static conditions. By the characterization of XRD, SEM, FT-IR,11B MAS NMR, the resultant B-Beta had high purity, uniformitarian morphology, sub-micron-sized particles. The B atoms were implanted into the zeilite framework. In addition, the results showed that the obtained B-Beta in the mixed system of inorganic base and fluoride had smaller crystal size than that of product synthesized from the single inorganic base or fluoride system; we could receive higher product yield and need shorter crystallization time by this method.We successfully prepared high Sn content Beta zeolites by gas-solid reaction. The preparation process consisted of two steps. Firstly, we treated the parent B-Beta zeolite using a certain concentration of hydrochloric acid. Secondly, the treated B-Beta zeolite contacted with the SnCl4vapor in the N2atmosphere at a particular temperature. By the characterization of XRD, FT-IR, UV-Vis, the results suggested that the Sn species was incorporated into the zeolite framework occupied predominately the tetrahedral coordination sites and the Sn-Beta zeolite exhibited good Lewis site.Through investigation of reaction conditions, we studied the catalytic properties of Sn--Beta in the the isomerization of glucose into fructose in water. The Sn-Beta by post-synthesis method showed high catalytic activity at T=120℃, t=2h.