表面活性剂Tween对TS-1合成及催化性能影响的研究

Titanium silicalite (TS-1) was synthesized using small amount of TPAOH as template in the presence of Tween. The samples were characterized by XRD, FTIR, BET, UV-Vis, and SEM techniques. The XRD results showed that all the samples were fully crystallized and had characteristic MFI topological structure. FTIR spectroscopy for all the samples showed strong characteristic band at 960 cm－1, which indicated that titanium has incorporated into the silicalite framework. No band at 330 nm in the UV-Vis spectroscopy was observed, indicating no extra framework TiO2 (antase) existed in the samples prepared with Tween. The result of SEM showed that the crystal size of the TS-1 zeolite was more uniform. In the micelle solution with appropriate amount of Tween, the synergic effect between the surfactant and template molecules could enhance the interaction between template and silica and/or titanium species, also induced orientation reaction between them, which avoided the formation of anatase (TiO2). Such behavior also helped in reducing the concentration of excess template molecules required as space filler. Thus, the addition of Tween 20, Tween 40, Tween 60 and Tween 80 could not only greatly cut down the amount of TPAOH, but also improve the catalytic performance of TS-1 zeolite, and Tween 40 was found to be the most effective one among the four kinds of nonionic surfactants. It was conformed that when the molar ratio of Tween 40/TPAOH was 0.02, the conversion of hydrogen peroxide（x-H2O2） was 98.1% ,and the selectivity and yield of propene oxide（PO）could reach 96.1% and 94.3%, respectively.