合成条件对磷钨杂多酸季铵盐催化剂性能的影响

 采用廉价的季铵盐［C16H33(CH3)3(70%)+C18H37(CH3)3(30%)］N+Cl-(简记为Q+Cl-)代替［C5H5NC16H33］+Cl-作为相转移剂,制备了一种新型的反应控制相转移催化剂,详细考察了制备过程中各因素对催化剂性能的影响,确定了适宜的催化剂制备条件,同时对催化剂的 31P NMR上的各峰进行了归属. 研究结果表明,在1-辛烯环氧化反应中,催化剂各组分在双氧水作用下能够相互转化形成合适比例的多组分复合催化剂,催化活性较高,但任一组分单独作用时催化活性则较低.

Influence of Preparation Conditions on Catalytic Activity of Heteropolyphosphatotungstate Catalyst

Reaction-controlled phase-transfer catalysts have advantages of both homogeneous and heterogeneous catalysts. For decreasing the catalyst preparation cost and making the synthesis method practical, a new reaction-controlled phase-transfer catalyst was synthesized under the improved preparation conditions using C_ 16H_ 33(CH_3)_3(70%) C_ 18H_ 37(CH_3)_3(30%)]N Cl-(labeled as Q Cl-) instead of C_5H_5NC_ 16H_ 33] Cl- as the phase-transfer agent. The influence of preparation conditions on the catalyst activity was investigated, and the catalyst was analyzed by 31P NMR spectroscopy. Combining the 31P NMR results with the catalyst activity for the 1-octene epoxidation, it was found that the components of the catalyst can interconvert in the presence of hydrogen peroxide, which results in the formation of a complex catalyst with high activity for the 1-octene epoxidation. But the catalyst with one component shows poor catalytic activity in the 1-octene epoxidation.