采用直接合成法将磷钨杂多酸( HPWs)固载到金属-有机骨架材料MIL-101的介孔笼中,制得新型HP-Ws@MIL-101多相催化剂。利用XRD、N2吸附、扫描电镜( SEM)、XPS、UV-Vis DRS、Raman和FT-IR等手段对该催化剂进行了表征,并研究了其在环戊烯选择氧化制备戊二醛反应中的催化性能。结果表明,磷钨杂多酸高度分散在金属-有机骨架MIL-101的介孔笼中,将磷钨杂多酸固载到MIL-101上后,能够很好地保持磷钨杂多酸的Keggin结构和载体MIL-101的晶体骨架结构。 HPWs@MIL-101催化剂的催化性能远高于传统浸渍法制备的催化剂的催化性能,当磷钨杂多酸的负载量为12.5%( w)时,HPWs@MIL-101表现出最优的催化性能,环戊烯转化率高达100%,戊二醛的得率达到78.7%。重复实验表明该催化剂具有较高的稳定性,使用三次后,GA的得率仍然达到74.1%。
The novel heterogeneous HPWs@MIL-101 catalyst was prepared by the direct synthesis method using chromium (Ⅲ) terephthalate metal organic framework MIL-101 as the support and phosphotungstic acids( HPWs) as the active component. The as-prepared material was systemically characterized by means of XRD, N2 adsorption, SEM, XPS, UV-Vis DRS, Raman, and FT-IR techniques and its catalytic performance was investigated for the selective oxidation of cyclopentene( CPE) to glutaraldehyde( GA) . It was found HPWs were highly dispersed in the mesoporous cages of MIL-101 and the Keggin structure of HPWs and the crystal structure of MIL-101 were both perfectly kept after HPWs incorporation. The CPE conversion and GA selectivty reached 100%and 78. 7%over the 12. 5%( w) HPWs@MIL-101 catalyst,respectively,which were much higher than those over the catalyst prepared by the conditional impregnation method. The reused experiments demonstrated the HPWs@MIL-101 catalyst was very stable and GA selectivity was still 74. 1%after the third reaction cycle.