酸碱改性ZSM-5分子筛及其噻吩烷基化性能的研究

首先采用碱处理HZSM-5分子筛,然后采用不同浓度的柠檬酸酸洗碱处理后的HZSM-5分子筛,制备具有微孔-介孔多级孔HZSM-5分子筛.通过XRD、SEM、BET和NH3-TPD等表征手段对处理后催化剂进行表征,考察了碱处理后酸洗对HZSM-5分子筛孔结构性质的影响,结果表明:适当浓度的柠檬酸酸洗碱处理后的ZSM-5分子筛,能够清除掉残留在分子筛孔道内的杂质,增大了分子筛的孔径;在小型固定床反应器上,研究了改性前后分子筛的噻吩烷基化反应活性和稳定性,结果表明:碱处理后采用适当浓度的柠檬酸酸洗后,催化剂的初活性虽然低于碱改性的分子筛,但稳定性较好,更适合噻吩烷基化反应.

Study on Thiophene Alkylation Properties of ZSM-5 Zeolite with Acid and Alkali Modification

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.