钛硅沸石的制备及其选择氧化性能

Preparation and selective oxidation properties of titanium silicalite

采用水热晶化法和气固相同晶取代法成功地合成了Ｔｉ－ＺＳＭ－５和Ｔｉ－ＺＳＭ－１１型分子筛；应用苯酚羟基化、苯乙烯氧化和丙烯环氧化反应为探针，详细考察了不同方法合成的钛硅沸石的催化性能．结果表明：非贵模板剂合成的钛硅沸石应用于苯酚羟基化反应，苯酚转化率为２０％～３０％（苯酚／双氧水为１，摩尔比）；增加苯酚与双氧水的比值，苯酚转化率迅速下降．另外，用ＴｉＣｌ４取代法合成的钛硅沸石，钛原子进入骨架的状态与水热法是不完全相同的．气固相同晶取代法合成的钛硅沸石应用于苯乙烯氧化反应，苯乙烯转化率可达４０％，芳醛总选择性在９０％以上（苯乙烯和双氧水的摩尔比为２．２）；该钛硅沸石应用于丙烯环氧化反应，可以高选择性地生成环氧丙烷．非贵模板剂合成的钛硅沸石的理化性能与ＴＳ－１相似，但其理化性能和催化性能之间无对应关系．

Ti ZSM 5 and Ti ZSM 11 type molecular sieves have been successfully synthesized with hydrothermal synthesis and gas solid isomorphous replacement. The catalytic properties of titanium silicalite synthesized with different methods were studied in detail using phenol hydroxylation, styrene oxidation and propylene epoxidation as test reaction. The results show that, using the titanium silicalite synthesized with cheap templating agent to catalyze the hydroxylation of phenol, the conversion of phenol is 20% 30% (the molar ratio of phenol to H 2O 2 is 1). Moreover, the conversion of phenol decreases drastically with the increase in the molar ratio of phenol to H 2O 2. In the titanium silicalite synthesized with TiCl 4 substitution method, the environment of titanium atom incorporating into the framework is different from that synthesized with hydrothermal method. Using this catalyst in the oxidation of styrene, the conversion of styrene is up to 40%, and the selectivity of aromatic aldehyde is up to 90% (the molar ratio of styrene to H 2O 2 is 2.2). Using this catalyst in the epoxidation of propylene, it can high selectively produce propylene oxide. The physical chemical properties of titanium silicalite synthesized with cheap templating agent are similar to that of TS 1. However, the physical chemical properties are not proportional to the catalytic properties.