Catalytic epoxidation of cyclohexene over mesoporous-silica immobilized Keggin-type tungstophosphoric acid

A series of aminosilylated mesoporous silica (SBA-15) samples with different contents of (3-aminopropyl) triethoxysilane (APTES), synthesized using a simple one-pot method, were used as hosts for immobilization of Keggin-type 12-phosphotungstic acid (H3PW12O40). The loading of H3PW12O40 increased with increasing content of grafted APTES. The obtained materials were calcined at different temperatures, and the tungsten species were highly dispersed inside the SBA-15 channels. The catalytic activities of these samples were tested in heterogeneous oxidation of cyclohexene using H2O2 as the oxidant. The effects of different loadings and treatment temperatures on the activities of the catalysts were also investigated. The catalysts calcined at 400 °C showed high catalytic activities and reusabilities.

摘要 采用共合成法制备了一系列不同硅氨基含量的介孔氧化硅 SBA-15, 在其孔道中引入 Keggin 型钨磷酸, 且其含量随硅氨基含量的增加而增加. 考察了不同处理温度下杂多酸的热稳定性, 发现焙烧后钨物种能在 SBA-15 孔道内高度分散. 以 H2O2 为氧化剂, 研究了该催化剂在环己烯环氧化反应中的催化活性, 考察了杂多酸负载量和焙烧温度对催化活性的影响. 结果表明, 400 °C 处理后的钨磷酸催化剂具有高的反应活性和重复使用性能.

Graphical abstractA simple method was used to prepare mesoporous-silica- immobilized Keggin-type tungstophosphoric acid. The resulting catalysts showed high catalytic activities and reusabilities in heterogeneous oxidation of cyclohexene using H2O2 as the oxidant.Figure optionsDownload full-size imageDownload as PowerPoint slide