The Synthesis And Characterization Of Special Zeolite ZSM-5

As one kind of widely used catalyst active component, ZSM-5 zeolite was received a great lot of research. But there is not report about comparison between microparticle and nanoparticle, pure ZSM-5 and co-crystalline, unsupported and supported ZSM-5 zeolite in physicochemical and catalytical characters. Nanocrystalline zeolite ZSM-5 was synthesized by the surface-wetting method with TPA+ as the template; co-crystalline zeolite of ZSM-5/MOR was synthesized with n-butylamine as the template; Composite ZSM-5/SiO2 was synthesized by the surface-wetting method with TEA+ as the template; and the physicochemical characters of the zeolites were researched.The nanocrystalline zeolites have been investigated compared with microcrystalline zeolite ; The co-crystalline zeolites have been investigated compared with zeolite ZSM-5, mordenite and their mechanical mixture for structures, acidities by means of XRD, SEM, N2-adsorption and NH3-TPD. The catalytic activity of the zeolites was studied in an impulsive micro reactor. It is found that the BET of nanocrystalline is larger than the microcrystalline,in comparison with microcrystalline zeolite, the nanocrystalline zeolite showed higher activity for the cracking of n-tetradecane, the conversion of the n-tetradecane on nanocrystalline zeolite ZSM-5 was 64.9%, but the conversion of the n-tetradecane on microcrystalline zeolite ZSM-5 was 49.1%. From the process of the synthesis, we concluded the method of surface-wetting is on the basis of the liquid phase transformation. The crystallines in the co-crystalline zeolites do not show physical mixture but inlayed each other. The pore size distribution of the co-crystalline zeolites is distinct from those of ZSM-5 and mordenite. Total acid amount of the three kinds of zeolite is ZSM-5>MOR>ZSM-5/MOR. In these three zeolites, co-crystalline showed better conversion on aromatization of methanol, the conversion of methanol is 12.3%, 4.0% more than ZSM-5, mordenite zeolite respectively. Co-crystalline has best activity of toluene disproportionation and it's yield of xylene is 14.8%, 4.0% more than ZSM-5, MOR respectively.