不同来源的钛硅沸石的孔结构,酸性和催化性能

用气固相类质同晶取代和水热方法合成了Ｔｉ－ＺＳＭ－５和ＴＳ－１沸石，对它们的组成、孔结构、酸性和催化活性进行了比较。以季铵盐为模板剂水热合成的无铝ＴＳ－１沸石骨架Ｔｉ含量高，表面无强酸位，且随骨架Ｔｉ含量增加，沸石晶内由缺陷造成的二次孔数量增多。类质同晶取代的Ｔｉ－ＺＳＭ－５沸石骨架Ｔｉ含量有限，样品内尚保留部分骨架Ａｌ，沸石表面强弱酸位同时存在。增加沸石骨架Ｔｉ含量和晶内二次孔对提高苯酚过氧化氢

Pore Structure,Surface Acidity and Catalytic Activity of Ti-Silicalite Prepared by Different Methods

Ti-ZSM-5 and TS-1 zeolites were prepared by vapor-solid isomorphous substitution and hydrothermal synthesis methods respectively. The chemical composition, pore structure,surface acidity and catalytic activity of the two types of Ti-containing zeolites with MFI structure were tested and compared. TS-1 zeolites obtained from hydrothermal synthesis with tetraalkyl ammonium halides as templates have a higher Ti content in the zeolite framework and lack of strong acid sites on the surface.As the amount of Ti incorporated into the zeolite framework is increased,the size of the hysteresis loops on the N_2 adsorption and desorption isotherms is also increased,implying that more secondary mesopores are formed in the zeolite from the lattice defects. The Ti content of the isomorphous substituted Ti-ZSM-5 zeolites is limited,and a part of Al still remains in the zeolite framework.Both weak and strong acid sites exist on the surface of Ti-ZSM-5 zeolites. An increase in the Ti content and the secondary pores in the zeolite lattice is in favor of its catalytic activity for the oxidation of phenol with hydrogen peroxide, but the presence of surface strong acid sites reduces its catalytic activity and selectivity for the same reaction.