新型W-HMS催化剂的直接合成、表征及催化性能

采用直接合成方法将W~(6+)固载到六方介孔全硅HMS分子筛上,制成新型W-HMS非均相催化剂。利用UV-Vis漫反射和吡啶(Py)-FTIR方法对W-HMS催化剂进行了表征,研究了该催化剂在环戊烯选择氧化制备戊二醛反应中的催化性能,并探讨了该多相催化反应的机理。实验结果表明,钨物种含量对W-HMS催化剂的结构和催化性能有显著的影响,当n(Si)∶n(W)=30时,该催化剂表现出优良的催化性能,环戊烯的转化率和戊二醛的选择性分别达到100.0%和76.3%。UV-Vis漫反射表征结果显示,该催化剂中钨物种以高度分散状态存在于催化剂骨架中,并且钨物种主要以孤立的WO_4]~(2-)四面体、单聚或低聚的形态存在;Py-FTIR表征结果显示,高度分散的钨物种提供了更多的酸中心,可推测为该反应的活性中心,并且较强的B酸中心有利于环戊烯的催化氧化。

Direct Synthesis, Characterization and Catalytic Performance of Novel W-HMS Catalyst

Novel heterogeneous W-HMS catalysts were prepared through direct synthesis,in which W~(6+) s were immobilized on HMS molecular sieves,and were characterized by means of UV-Vis diffuse reflectance spectrometry and pyridine(Py)-FTIR techniques.Performances of the W-HMS catalysts in selective oxidation of cyclopentene(CPE) to glutaraldehyde(GA) were investigated.The results indicated that effects of the tungsten content on structures and performances of the catalysts were obvious.The W-HMS(30) catalyst with n(...