Synthesis And Post-treatment Of ZSM-5and Its Catalytic Performances In The Alkylation Of Benzene With Methanol

Creating mesoporous in microporous molecular sieves is a kind of effective method modifying zeolite into hierarchical zeolite. ZSM-5was synthesized by hydrothermal crystallization method with1,6-hexanediol as the template. The synthesized ZSM-5zeolite was treated with sodium hydroxide solution. The influences of different conditions on synthesis and post-treatment were investigated.The samples were characterized by XRD, FT-IR, SEM, NH3-TPD, N2adsorption at77K. ZSM-5zeolites were successfully synthesized with the synthesis conditions as follows: SiO2/Al2O3=20～100, SiO2/1,6-HDO=2.5～6, Na2O/SiO2=0.2～0.4, T=160℃～200℃, t=48-72h. When ZSM-5zeolites were treated by NaOH solution, under certain conditions, it led to slit shape mesoporous, increase in weak acid quantity and decrease in strong acid quantity. The crystalline, mesoporous surface area and micropore volume of ZSM-5were improved by further weak acid treated.Compared to the untreated ZSM-5, alkali treated ZSM-5showed high benzene conversion, selectivity and yields for the toluene and xylene in the benzene alkylation with methanol.