ZnO-SiO_2复合催化剂的制备及其在碳酸二甲酯合成中的作用

Preparation of zinc oxide/silicon dioxide composite catalyst and its action in synthesis of dimethyl carbonate

以沉淀法制备出了复合催化剂ZnO-SiO_2,用XRD、SEM、FT-IR等手段对该催化剂进行了表征。考察了摩尔比、煅烧温度不同的ZnO-SiO_2复合催化剂对尿素醇解合成碳酸二甲酯的催化活性。结果表明,ZnO-SiO_2复合催化剂的活性随摩尔比增大逐渐降低。摩尔比为1时活性达到最高;煅烧温度不同时,催化剂具有不同的活性,在600℃下煅烧制得的催化剂的活性最好;当n(ZnO):n (SiO_2)为1,煅烧温度为600℃时,碳酸二甲酯(DMC)收率达到5.42%。

ZnO-SiO2 composite powder catalysts are prepared by precipitation method in this paper. By means of XRD, SEM and FT-IR, the properties of catalysts are also characterized. The catalytic activities of a series of composite catalysts for alcoholysis of urea have been studied in different molar ratio and different calcining temperature. According to the experimental results, activity of ZnO-SiO2 composite catalysts decrease gradually with increasing in the molar ratio of zinc oxide to silicon dioxide, and catalytic activity of ZnO-SiO2 composite catalysts change with different calcining temperature. It was also observed that the yields of dimethyl carbonate （DMC） attain 5.42% at n（ZnO）：n（SiO2）=l and 600℃ of calcining temperature.