通过原位负载法合成了一种新的具有可逆负载特性的磷钨杂多酸盐/SiO2催化剂,并应用于氯丙烯环氧化反应.在反应温度65℃的条件下,系统研究了原位负载过程中反应时间、调节剂Na2HPO4用量、烯烃/H2O2摩尔比和硅烷化硅胶粒度大小等因素对环氧化反应的影响,并考察了催化剂的循环使用效果.实验结果表明,在适宜的反应条件下,初始反应环氧氯丙烷的产率达86.5%,催化剂循环使用3次,催化活性基本保持不变.
The epoxidation of allyl chloride to epichlorohydrin was investigated using a new reversibly supported catalyst, heteropolyphosphatotungstates/silanized silica gel, which was generated in situ in the epoxidation reaction. The effects of reaction time, Na2HPO4 amount, ratio of allyl chloride to H2O2, and particle size of silanized silica gel were examined at a reaction temperature of 65℃. The results showed that the epichlorohydrin yield of the initial epoxidation reaction reached 86.5 % under the optimized reaction conditions. The catalyst could be reused three times without significant loss of catalytic activity.