中孔分子筛Al/SO_4^(2-)/Al-MCM-41的合成、表征及催化性能

Synthesis,Characterization and Catalytic Performance of Mesoporous Molucular Sieves Al/SO_4^(2-)/Al-MCM-41

分别用H2SO4和Al2(SO4)3对中孔分子筛Al-MCM-41进行改性,得到了中孔分子筛SO42-/Al-MCM-41和Al/SO24-/Al-MCM-41。采用X射线多晶衍射(XRD)、红外光谱(FT-IR)、N2吸附-脱附和NH3程序升温脱附(NH3-TPD)等测试技术对样品的结构和表面酸性进行了表征。分别用Al-MCM-41、SO24-/Al-MCM-41和Al/SO24-/Al-MCM-41催化合成丙酸香叶酯,比较了三者的催化性能。结果表明,用Al2(SO4)3改性中孔分子筛Al-MCM-41,能得到仍保持着六方介孔结构的中孔分子筛Al/SO24-/Al-MCM-41,其酸性和催化性能比用H2SO4改性得到的SO24-/Al-MCM-41更强;用Al2(SO4)3改性不仅SO24-附着在了分子筛骨架上,而且Al也接枝在了分子筛骨架上。

SO4^2-/Al-MCM-41 and A1/SO24-/A1-MCM-41 were prepared by modifying A1-MCM-41 with H2SO4 and A12 （ SO4 ） 3, respectively. Their structures and surface acidity were characterized by X-ray diffraction （XRD） , Fourier transform infrared spectroscopy （FT-IR） , N2 adsorption-desorption and NH3 temperature programmed desorption （NH3- TPD）. Al-MCM-41, SO24-/Al-MCM-41 and Al/SO4^2-/Al-MCM-41 were used respectively as catalyst for the synthesis of geranyl propionate （GP）, and their catalytic properties were compared. The results showed that the mesoporous molecular sieves Al/SO4^2-/Al-MCM-41 which still keep hexagonal mesoporous structure can be obtained by modifying Al-MCM-41 with A12 （SO4） 3＇ The acidity and catalytic performance of Al/SO4^2-/Al-MCM-41 is stronger than that of SO4^2-/Al-MCM-41 by modifying Al-MCM-41 with H2SO4. While Al2 （SO4）3 modifying Al-MCM-41, not only SO4^2- adheres to the framework of molecular sieve, and Al is also grafted to the framework.