NaPMoO/Ti-MCM-41催化环己烯环氧化反应

采用浸渍法制备了混合氧化物NaPMoO/Ti-MCM-41(n)(n为载体钛硅比)催化剂,考察其在以H2O2为氧化剂的环己烯环氧化反应中的催化性能,并用XRD、UV-Vis、IR、N2吸附-脱附、XPS及H2-TPR等测试技术对催化剂进行表征.结果表明:NPMO/Ti-MCM-41(0.2)的环己烯转化率、环氧环己烷选择性及H2O2利用率达到最高,分别为27.50%、75.31%和78.31%.这归因于负载型NPMO中的MoO3还原能力得到提高;载体Ti-MCM-41中Ti物种进一步促进MoO3的还原能力,从而有利于其与双氧水形成过氧化物活性中间体,使催化性能和双氧水的利用率得到提高.其中负载后的载体Ti-MCM-41孔结构遭到破坏,形成无定形TiOx物种.

Epoxidation Reaction of Cyclohexene over NaPMoO/ Ti-MCM-41

Mixed oxides NaPMoO/Ti-MCM-41(n)(n=molar ratio of Ti/Si) catalysts were prepared by impregnation method for the epoxidation reaction of cyclohexene using H2O2 as oxygen source. The obtained catalysts were characterized by XRD, UV, IR, N2 adsorption-desorption, XPS and H2-TPR. The results showed that the conversion of cyclohexene, selectivity to cyclohexene oxide and utilization of H2O2 on NPMO/Ti-MCM-41(0.2) reached the highest values ( 27.50%, 75.31% and 78.31% respectively). These changes can be attributed to that the reduced ability of MoO3 contained in NPMO was improved after the NPMO was loaded, Ti species in the Ti-MCM-41 supports can promote the reduced ability of MoO3 further more. Structures of Ti-MCM-41 were destructed after loaded, and turned into amorphous TiOx species.