关键词: Ti-ZSM-5, TS-1, N₂吸附, NH₃-TPD, 苯酚过氧化氢羟化

Abstract: 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 MFIstructure 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 N₂ 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.

Key words: Ti-ZSM-5, TS-1, N₂ adsorption, NH₃-TPD, Hydroxylation of phenol with H₂O₂