W-HMS催化剂的制备及评价

Preparation and Evaluation of W-HMS Catalyst

采用原位合成法将W6+引入六方介孔全硅分子筛(HM S)骨架中,制备了应用于环戊烯催化氧化合成戊二醛反应的W-HM S催化剂。实验结果表明:钨酸是制备W-HM S催化剂很好的钨源,以钨酸为原料制备的催化剂具有很高的催化活性和选择性,使溶剂叔丁醇用量大为减少。采用小角度X射线衍射(XRD)、电子能谱扫描(EDS)以及电位滴定法对所制备的催化剂结构进行表征,显示催化性能与W含量密切相关。在nS i∶nW≥30时,催化剂能保持完好的HM S分子筛结构,W原子以嵌入HM S骨架的形式高度分散于载体内表面,构成催化活性中心。在优化的反应条件下,环戊烯氧化反应转化率达到100%,生成戊二醛的收率达到79.3%,而且催化剂具有连续套用7次的良好稳定性。

The heterogeneous W-HMS catalyst was in-situ prepared by immobilization of tungstic acid on hexagonal mesoporous silica （HMS）. It was used to synthesize glutaraldehyde from cyclopentene, The reaction results show that the catalytic activity and selectivity of W-HMS prepared with tungstic acid is better than that prepared with sodium tungstate. reduced. Based on the characterizations by means And the consumption of t-BuOH also is successfully of small-angle XRD, EDS and potentiometric titration analysis, the catalyst remains a typical structure of HMS and tungsten species can stably exist in the silicabased matrix of HMS when nSi ： nw≥30. Complete conversion for cyclopentene and high yield of 79.3% for glutaraldehyde are obtained over the W-HMS prepared with tungstic acid at optimum condition. Finally, the durability of our catalyst is verified by carrying out a catalyst-recycling test over seven cycles.