氧化羰基化合成碳酸二苯酯中纳米锰氧化物气凝胶载体的制备及表征

Preparation and characterization of nano Mn oxide aerogel carriers used for synthesis of diphenyl carbonate through oxidative carbonylation

分别采用柠檬酸络合常压干燥法、环氧丙烷促凝冷冻干燥法制备了3种纳米锰氧化物气凝胶材料,利用X射线衍射仪、比表面积及孔隙分布测定仪、扫描电镜及透射电镜等测试手段对其进行表征,并测试各样品负载活性物后在氧化羰基化合成碳酸二苯酯中的催化效果。结果表明,采用环氧丙烷促凝冷冻干燥法且加入TAA制备的锰氧化物气凝胶材料呈现纳米花菜状的多晶结构,具有良好的量子效应;将该凝胶负载质量分数为1%的Pd后用于催化苯酚氧化羰基化合成碳酸二苯酯,当反应总压为5 MPa(其中氧气体积分数约为7%)、反应温度为70℃、反应时间为4 h时,碳酸二苯酯的单程收率可达23.34%,选择性为99.16%,催化效果良好。

Three nano Mn oxide aerogels were prepared by the methods of citric acid complex via ambient drying,propylene oxide promoting freeze-drying,respectively.And the samples prepared were investigated by XRD,BET,SEM and HRTEM.The Mn3O4 nanostructure aerogels were used as catalyst carriers for the synthesis of diphenyl carbonate(DPC)by oxidative carbonylation of phenol.The results show that the nano Mn oxide aerogel prepared by the propylene oxides promoting freeze-drying method has a nano cauliflower shape and good quantum effect.After loading of mass fraction 1% Pd,the aerogel was applied in the synthesis of diphenyl carbonate through oxidative carbonylation of phenol and the single pass yield of the catalyst obtained is 23.34% with the selectivity up to 99.16%when the total reaction pressure is 5MPa(the volume fraction of oxygen is about 7%),reaction time is 6hand the reaction temperature is 70 ℃.