介孔固体超强酸催化剂的制备与结构表征

Preparation and Structure Characterization of Mesoporous Solid Superacid Catalysts

以累托土为基质 ,采用硅锆双组分交联剂和SO2 -4改性的方法 ,研制交联粘土介孔固体超强酸 (SO2 -4/SiZrR) ,借助XRD ,BET法 ,FT IR ,Hammett指示剂法 ,NH3 TPD ,Py IR和DTA等现代分析测试方法 ,表征其结构 .实验结果表明 :5 0 0℃焙烧后 ,SO2 -4/SiZrR的Hammett酸度函数Ho<-11 93 ,最可几孔径分布在 2 3nm左右 ,具有超强酸性和介孔结构 ;其超强酸中心属于L酸中心 ,是主要的催化活性中心 ;硅锆双组分交联柱能使交联粘土的热稳定性提高 。

By utilizing rectorite as matrix, the mesoporous solid superacid in form of pillared clays (SO 2- 4/SiZrR), pillared by Si Zr bipillaring agent and modified subsequently by SO 2- 4, was prepared. Its structure was characterized by means of XRD, BET, FT IR, Hammett indicator, NH 3 TPD, Py IR, DTA etc . The results show that after being calcined at 500 ℃, SO 2- 4/SiZrR exhibited superacidity and mesoporous structure with the Hammett acidity function H o<-11 93 and the most probable pore size at ca . 2 3 nm. The superacid sites were attributed to Lewis acid sites and proved to be dominant active center. The Si Zr bipillars can enhance the thermal stability of the resulting catalysts substantially. By utilizing rectorite as matrix, the thermal stability of pillared clay is, in particular, higher than that of pillared clay which utilizes montmorillonite as matrix.