The Study Of Catalyst Modified And Reaction Characteristics For Benzene-Methanol Alkylation

This paper mainly focuses on the alkylation reaction of benzene with methanol, in order to find a new method for productsion of para-xylene. The study is divided into two parts, one is the research of the catalytic properties of ZSM-5zeolite, and it discussed the influence of synthesis method, preparation method, modified method as well as active component screening on ZSM-5zeolite catalytic properties, the other one is to study the different processs conditions on the influence of the alkylation reaction. The acidic sites and surface structure of the ZSM-5zeolites was characterized by means of BET, XRD, NH3-TPD, and it found that acid amount, acid strength, porous structure, specific surface area and pore volume have a great influence on the catalytic properties.Different Si/Al ZSM-5zeolite catalytic performance was evaluated on the fixed-bed microreactor, and the result show that ZSM-5zeolite is more appropriate for the Si/Al range from145to220. Process conditions was investigated which was used hierarchical ZSM-5zeolite as catalyst, and obtained optimum conditions is T=773K, P=0.18MPa, WHSV=8h-1, methanol:benzene=1mol:1mol, in this condition, the conversion of benzene is53.60%, the selectivity of toluene and xylene is90.29%.Ordinary HZSM-5zeolites doped with different concentrations of HF and Pt loading, its catalytic properties are significantly increased, the selectivity of toluene and xylene are all more than90%, hierarchical HZSM-5doped with6%HF, the conversion of benzene is52.30%, the selectivity of toluene and xylene is91.32%.Ordinary HZSM-5which was introducted of mesoporous through NaOH, NaA102alkali treatment and HC1washing two-step method, its conversion of benzene increased by10%than ordinary HZSM-5, and the selectivity of toluene and xylene was also increased by4%, its catalytic performance has reached the level of hierarchical HZSM-5. and it has a very good industrial development and application prospects.