钛硅分子筛催化丙烯环氧化反应条件的研究

Effect of Reaction Condition on Propylene Epoxidation Catalyzed by Titanium Silicalite

以用四丙基溴化铵（ＴＰＡＢｒ）为模板剂合成的钛硅分子筛ＴＳ－１为催化剂，Ｈ２Ｏ２为氧化剂，系统地研究了丙烯环氧化反应的规律．考察了反应温度、丙烯压力、催化剂用量、反应时间等反应参数的影响，找到了较佳的丙烯环氧化反应条件．研究发现：温度对反应结果有显著影响，随反应温度升高，Ｈ２Ｏ２转化率提高，但环氧丙烷（ＰＯ）选择性降低；丙烯压力对反应结果无明显影响；催化剂不经再生处理，多次重复使用，产物分布保持不变，Ｈ２Ｏ２转化率略有下降；少量水的存在对丙烯环氧化反应影响不大，但若以水代替甲醇为溶剂，反应速率降低，且产物中出现大量丙二醇；以叔丁基过氧化氢代替Ｈ２Ｏ２为氧化剂时，ＴＳ－１不具有催化活性．

Propylene epoxidation catalyzed by TS 1 synthesized with TPABr (Tetrapropyl ammonium bromide) as template has been investigated systematically. Effect of reaction parameters such as temperature, propylene pressure, time, catalyst amount etc. were discussed and the optimum reaction condition was found. The pressure of propylene has no effect on propylene epoxidation, but the temperature has a significant effect. As the temperature rises, the H 2O 2 conversion increase and PO selectivity decreases proporcionally. H 2O 2 conversion decreases slowly if the same catalyst is used many times without regeneration, but product distribution changes little. Water at low concentration does not influence the reaction, but if water is used instead of methanol as solvent, the reaction rate decreases remarkablly and a large amount of glycol forms. TS 1 shows no activity if TBHP (Tert butyl hydroperoxide) is used as the oxidant instead of H 2O 2.