Abstract: ZSM-5 zeolites were firstly treated by alkali solution.Then the HZSM-5 molecules of alkali treatment were washed by useing different concentrations of citric acid to prepare the HZSM-5 multiple microporous and mesoporous.The samples were characterized by XRD,SEM,N2 desorption,NH3-TPD and other.It has been investigated that the effect of acid washing after alkaline treatment on the structure and properties of HZSM-5 molecular sieves,It is show that:ZSM-5 molecular sieve catalyst after Alkali treatment are treated by proper concentration citric acid,which can clear the impurities remaining in the molecular sieve channel and expand the pore size of molecular sieve.The initial activity and stability of each catalyst thiophene alkylation before and after modification were studied on a small fixed bed reactor.It is show that through after alkali treatment,and washed with proper concentration of citric acid,the initial activity of the catalyst is lower than the alkali modified zeolite,but it has better stability,and which is more suitable for thiophene alkylation.

Key words: ZSM-5 zeolites were firstly treated by alkali solution.Then the HZSM-5 molecules of alkali treatment were washed by useing different concentrations of citric acid to prepare the HZSM-5 multiple microporous and mesoporous.The samples were characterized by XRD,SEM,N2 desorption,NH3-TPD and other.It has been investigated that the effect of acid washing after alkaline treatment on the structure and properties of HZSM-5 molecular sieves,It is show that:ZSM-5 molecular sieve catalyst after Alkali treatment are treated by proper concentration citric acid,which can clear the impurities remaining in the molecular sieve channel and expand the pore size of molecular sieve.The initial activity and stability of each catalyst thiophene alkylation before and after modification were studied on a small fixed bed reactor.It is show that through after alkali treatment,and washed with proper concentration of citric acid,the initial activity of the catalyst is lower than the alkali modified zeolite,but it has better stability,and which is more suitable for thiophene alkylation.