非均相催化一步合成碳酸二苯酯的研究 Ⅳ.活性组分及其负载方法对催化剂性能的影响

Study on Direct Synthesis of Diphenyl Carbonate through Heterogeneous Catalysis Ⅳ. Effects of Active Components and Their Supporting Methods on Catalyst Activity

采用浸渍法、沉淀法、混烧法和溶胶 凝胶法制备了非均相催化一步合成碳酸二苯酯 (DPC)所需的催化剂 ,对活性组分不同负载方法所得催化剂的比表面积和形貌进行了观测 ,并通过DPC合成实验评价了催化剂的催化性能 .结果表明 ,沉淀法所得催化剂的形貌及催化性能都比较好 .为了进一步寻找制备催化剂的适宜条件 ,就沉淀法所用的沉淀剂、活性物质及助剂对催化剂性能的影响进行了探讨 .结果表明 ,以NaOH为沉淀剂 ,以Na2 PdCl4 为活性物质 ,以Sn为助活性组分 ,其效果较好 ,DPC的选择性和收率分别可达 93%和 7 2 % .此外 。

The supported palladium catalysts with complex oxide La xPb yMn zO as the support for direct synthesis of diphenyl carbonate (DPC) were prepared by impregnation, precipitation, co-calcination and sol-gel methods respectively. The morphology and specific surface area of the catalysts were determined by SEM and specific surface area instrument. The results showed that the catalyst prepared by precipitation had uniform particles and pore diameters and good distribution of the active component Pd, and its surface area could amount to 1?337 m 2/g, but the agglomeration happened in other catalysts. The test for synthesis of DPC showed that the catalyst prepared by precipitation was better than the others. Furthermore, the effects of active substances, co-active substances and precipitating agents in the process of precipitation on the catalyst activity were also studied. The results revealed that the catalyst prepared with Na 2PdCl 4 as active substance, with NaOH as precipitating agent and with Sn as co-active substance has higher catalytic activity, and the selectivity and yield of DPC can reach 93% and 7.2% respectively.