Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Langmuir. 2011 Mar 15;27(6):2873-9. doi: 10.1021/la1048634. Epub 2011 Feb 4.
Single-site Ti-containing hierarchical macroporous silica with mesoporous frameworks (Ti-MMS) was successfully prepared by a solvent evaporation method using organic surfactant and poly(methyl methacrylate) (PMMA) colloidal crystals as the template. The formation of a well-defined macroporous structure composed of mesoporous silica walls was characterized by SEM and TEM observations. The successful incorporation of tetrahedrally coordinated Ti oxide moieties within their frameworks was also confirmed by spectroscopic techniques such as UV-vis and XAFS measurements. Comparative studies revealed that Ti-MMS exhibited higher catalytic activities for the epoxidation of linear α-olefin compared to Ti-containing mesoporous silica without macropores (Ti-MS). The reaction rate was significantly enhanced on Ti-MMS depending on increases in the alkyl chain length of linear α-olefins. It was also found that Ti-MMS showed good catalytic performance in the selective epoxidation of methyl oleate, which is a kind of unsaturated fatty acid methyl ester (FAME), under acid-free reaction conditions with tert-butylhydroperoxide (TBHP) because of the advantages of the combination of hierarchical macroporous and mesoporous structures.
采用溶剂挥发法，以有机表面活性剂和聚甲基丙烯酸甲酯（PMMA）胶体晶体为模板，成功制备了单分散 Ti 含介孔框架的分级大孔硅（Ti-MMS）。SEM 和 TEM 观察表明，形成了由介孔硅壁组成的具有良好定义的大孔结构。光谱技术如紫外-可见和 XAFS 测量也证实了 Ti 氧化物四面体配位部分成功掺入其骨架中。对比研究表明，Ti-MMS 对直链α-烯烃的环氧化反应表现出比没有大孔的含 Ti 介孔硅（Ti-MS）更高的催化活性。根据直链α-烯烃的烷基链长度的增加，Ti-MMS 的反应速率显著提高。还发现，Ti-MMS 在无酸条件下，以叔丁基过氧化氢（TBHP）作为氧化剂，在甲酯化油酸（一种不饱和脂肪酸甲酯，FAME）的选择性环氧化反应中表现出良好的催化性能，这是由于分级大孔和介孔结构的结合带来的优势。
