超重力法制备La_(0.5)Pb_(0.5)MnO_3及其在碳酸二苯酯合成中的应用

Preparation of La_(0.5)Pb_(0.5)MnO_3 powder by rotating packed bed and its application in synthesis of diphenyl carbonate

采用液液相共沉淀法在旋转填充床中合成钙钛矿型复合氧化物La0.5Pb0.5MnO3的前驱体,再经高温焙烧后制备出碳酸二苯酯合成催化剂的载体材料。考察了旋转填充床转速、反应物流量和添加分散剂PEG对La0.5Pb0.5MnO3物性的影响,通过XRD、BET、SEM、粒度分析手段对载体进行表征。结果表明,旋转填充床转速为1200r.min-1,反应物流量为80L.h-1,加入PEG10000时可制备出纯晶相的钙钛矿载体,相应的载钯(Pd占载体质量的0.5%)催化剂在氧化羰基化合成碳酸二苯酯反应中的活性最好。当反应总压为5MPa、CO/O2分压比为96:6、反应时间3h、反应温度65℃时,碳酸二苯酯收率可达13.30%。

The precursor of perovskite-type La0.5Pb0.5MnO3 oxide was prepared by co-precipitation method in rotating packed bed （RPB）.The effects of rotating speed of RPB,flow rates of reactants and the addition of PEG10000 on properties of La0.5Pb0.5MnO3 powder were investigated in combination with XRD,BET and SEM techniques.The results showed that the suitable conditions for preparation of precursor were as follows：rotating speed of 1200 r·min-1,reactants flow rate of 80 L·h-1 and PEG10000 as disperser.The corresponding La0.5Pb0.5MnO3 powder obtained by calcined was used as supports for Pd-catalytic synthesis of diphenyl carbonate（DPC） and showed good performance.The yield of DPC could achieve 13.30% when reaction temperature was 65℃,p=5 MPa,p（CO）：p（O2）=94：6,and reaction time 3 h.