组装在MCM-41和HMS上的Ti活性中心的催化作用

采用模板组装途径合成MCM－41和HMS两类中孔材料，探讨了在含模板剂和烧去模板剂的这两类载体上键合两类酒石酸钛络合物的组装方法。XRD和FT－IR结果表明：在焙烧过程中，MCM－41长程有序的中孔结构会发生退化而转化成与HMS相似的结构，并导致1219和580cm^-1红外带的消失，而诱发载体产生强度的Si-OH畸变。中孔HMS与钛化合物的键合作用会诱发载体产生弱的Si-OH畸变振动。在催化苯乙烯环氧化反应中，模板剂和酒石酸二乙酯（DET）配体对钛活性中心的调变作用可促进提高环氧选择性。

Catalytic Properties of Titanium Centers Assembled on MCM-41 and HMS

Mesoporous silicas MCM 41 and HMS were synthesized by the cooperative assembly of silica and surfactants. Two methods are raised to assemble titanium tartrate complexes over the untreated and calcined mesoporous carriers. The results of XRD and FT IR indicate that MCM 41's mesostructure with long range order will deteriorate, and be transformed into the mesostructure similar to HMS. This deterioration of the mesostructure arises the disappearance of 1?219 and 580?cm -1 , and then also causes a stronger aberrance of MCM 41's Si-OH groups. The binding of HMS with Ti complexes will induce the Si-OH groups of HMS to produce a weaker aberrance. In the epoxidation of styrene, the assembled Ti catalysts with the calcined mesoporous carriers exhibit the highest oxidative activity, and the assembled Ti catalysts with untreated mesoporous carriers possess the best epoxide selectivity. The modification of the templating agents and diethyl tartrate (DET) ligand on the Ti active centers will cause the decreases in the actalytic activity and the increases in the selectivity.