表面活性剂Tween对TS-1合成及催化性能影响的研究

以添加吐温的少量四丙基氢氧化铵（TPAOH）为模板剂，水热下合成了钛硅分子筛（TS-1）。采用FTIR、XRD、SEM、BET、UV-Vis等手段对分子筛进行表征。XRD结果表明,所得样品完全晶化，具有典型的MFI拓扑学结构;FTIR结果表明,样品在960 cm－1处出现了强吸收峰，表明钛已进入骨架;UV-Vis谱图表明，所合成样品在330 nm附近没有电子跃迁信号，表明其中没有锐钛矿型TiO2;SEM结果表明所合成样品的晶粒大小均匀。在添加适量吐温所得的胶团溶液中，模板剂分子与吐温之间的协同作用有助于TPAOH与硅、钛源定向反应，避免非骨架TiO2的生成，减少了TPAOH的用量，丙烯环氧化反应结果表明,吐温20、吐温40、吐温60及吐温80等非离子表面活性剂的添加都有助于降低模板剂（TPAOH）的用量和提高TS-1的催化活性，其中吐温40的影响尤为显著，吐温40/TPAOH摩尔比为0.02时，过氧化氢转化率达98.1%,环氧丙烷选择性和收率分别可达96.1％和94.3％。

Effect of tween on synthesis and catalytic performance of TS-1

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 TiO_2 (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 (TiO_2). 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_( H_2O_2)) was 98.1% ,and the selectivity and yield of propene oxide(PO)could reach 96.1% and 94.3%, respectively.