Study Of TS-1 With Micro-and Mesoporous Structure

Titanium silicalite (TS-1) is an efficient and stable catalyst for the epoxidation of propene with hydrogen peroxide. The epoxidation of propene catalyzed by TS-1 possesses many merits, such as mild reaction conditions, fast reaction rate, high product selectivity and without pollutants. However, TS-1 prepared with the traditional method can only catalyze the epoxidation of alkenes of small molecules due to its microporous structure and therefore limits its application. In this work, attempt have been made to synthesize TS-1 with both microporous and mesoporous structure which can catalyze the epoxidation of alkenes of large molecules.TS-1 was first synthesized by a hydrothermal method with tetrabutyl-titanate as organic Ti source, tetraethyl orthosilicate as Si source and tetrapropyl ammonium hydroxide (TPAOH) as template. Then, dual templates, TPAOH andβ-CD, and special template (carbon nano-materials) were used for the synthesis of TS-1 with both micropores and mesopores. The as-made TS-1 was also treated with NaOH solutions to generate mesopores. The samples were characterized by BET, FT-IR, XRD, UV-Vis diffuse reflectance, etc. The results showed that the TS-1 samples synthesized using TPAOH andβ-CD dual templates possessed mainly micropores and some mesopores with pore size of 3.9nm. However, the TS-1 samples synthesized using carbon nanotubes or nanorods as special templates had less mesopores with pore size of 3.9nm and 6.5nm. NaOH solution treatments generated more mesopores in the TS-1 sample with pore size of 3.9nm, but a portion of the titanium in the skeleton was removed as indicated by the appearance of anatase at 340nm in the UV-Vis diffuse reflectance spectra.