新型高疏水性富含甲基Ti-HMS介孔分子筛的制备、表征和催化性能

Preparation,characterization,and catalytic performance of a novel methyl-rich Ti-HMS mesoporous molecular sieve with high hydrophobicity

通过共缩合和气相甲基接枝两步法制备了新型的高疏水性富含甲基的Ti-HMS介孔分子筛.采用X光衍射、N2吸附、红外光谱、硅核磁、热重、元素分析(原子发射光谱)、紫外可见光谱等手段和亲水性实验对样品进行表征,并用环己烯环氧化反应进行催化性能测试.结果表明,经过两步接枝甲基后,Ti-HMS仍保持典型的介孔结构特征,拥有较多的甲基含量和较高的疏水性,催化环己烯环氧化活性和选择性均比共缩合法(一步接枝法)Ti-HMS有所提高.

A novel methyl-rich Ti-containing hexagonal mesoporous silica （Ti-HMS） molecular sieve with high hydrophobicity has been prepared by a two-step method involving co-condensation followed by vapor-phase methyl grafting. The sample was characterized by XRD,N2 adsorption,FTIR,UV-visible and 29Si NMR spectroscopies,TG,ICP-AES,and hydrophilicity measurements,and its catalytic performance was evaluated using the epoxidation of cyclohexene as a probe reaction. The Ti-HMS material retains a typical mesoporous structure and compared with a co-condensed Ti-HMS prepared in a one-step method possesses more methyl groups and higher hydrophobicity,and also exhibits better catalytic activity and selectivity.