负载型MoO3/SiO2催化剂催化酯交换合成草酸二苯酯的反应性能

 以钼酸铵、二氧化硅为原料，采用浸渍法制备了负载型的MoO₃/SiO₂催化剂，通过草酸二乙酯与苯酚酯交换反应合成草酸二苯酯。分别考察了不同载体，不同反应温度，不同反应时间，不同原料配比，不同负载量等条件对反应性能的影响，采用XRD、XPS表征技术研究了催化剂表面活性组分的分散状态对草酸二乙酯和苯酚酯交换反应的影响。其中，MoO3负载量6%的MoO3/SiO2催化剂催化性能最好，DEO转化率54.9%，DPO收率13.7%，EPO收率41.2%，目的产物DPO和EPO选择性的总选择性为100%。

CATALYTIC ACTIVITY OF SUPPORTED MoO3/SiO2 CATALYSTS IN ESTER EXCHANGE FOR SYNTHESIS OF DIPHENYL OXALATE

A series of supported MoO3/SiO2 catalysts with different MoO3 loadings were prepared by the impregnation method,and their activities in the transesterification of diethyl oxalate(DEO) with phenol to produce diphenyl oxalate(DPO) were tested.The catalysts were characterized by X-ray diffraction(XRD),and the relationship between the catalytic acticity of MoO3/SiO2 and the structure of MoO3 dispersed on the surface of SiO2 was studied in detail.The results indicated that amorphous MoO3 with high dispersion was favorable for the production of DPO.However,the formation of a great amount of the crystal MoO3 resulted in the decrease of catalytic activity.The effects of reaction temperature,reaction time,molar ratio of reagent,MoO3 loadings and so on were investigated.The catalyst of MoO3/SiO2 with 6%(mass fraction) MoO3 performed best,giving 54.9% conversion of DEO,13.7% yield of DPO,41.2% yield of ethyl phenyl oxalate(EPO) and 100% selectivity to target products of DPO and EPO.