Magnetic polymer microspheres based on phosphotungstic acid quaternary ammonium salt as an efficient heterogeneous catalyst for epoxidation of cyclohexene

The magnetic polymer microsphere catalysts based on phosphotungstic acid quaternary ammonium salt were designed and prepared in order to improve the performance and reusability of the catalysts during the epoxidation of cyclohexene. The structure, particle size and surface property of the new catalysts were characterized by FTIR, laser particle size analysis and SEM, respectively. And the reactivity of the catalysts was detected in cyclohexene epoxidation. Among the obtained catalysts, PS-double-D-PW4 catalyst exhibited the best catalytic performance and high stability for cyclohexene epoxidation. The results showed that the optimum yield of epoxycyclohexane was 83% with a selectivity above 95% after 7 h. And the catalyst still showed a conversion above 78% after six runs.