分别用硫酸铵、过硫酸铵对β分子筛进行改性,在微型固定床上评价了改性前后β分子筛对异丁烷/丁烯-1烷基化反应的催化性能。结果表明,改性后催化剂寿命延长近1倍,总C8产物选择性明显改善,这是因为改性后样品的中强酸量增加,有利于发生氢转移。随着催化剂的失活,硫酸铵改性的β分子筛上C8^-选择性迅速升高,而过硫酸铵改性时C9+选择性持续升高,可能意味着它们失活机理的不同。
The alkylation of isobutane/butene-1 over β zeolites modified with ammonium sulfate (β-(NH4)2 SO4 ) or persulfate (β-(NH4)2S2 O8) was investigated. The results indicated that the lifetimes of the catalysts almost doubled and total C8 selectivity was improved obviously after modification, which should be ascribed to the larger amount of middle-strong acid sites of modified samples, being favorable for enhancing the hydrogen transfer activity. Moreover, it is observed that C8^= selectivity increased significantly over β-(NH4 )2 SO4 , while the selectivity of C9^+ increased over β-(NH4)2S2O8 with the decrease of butene-1 conversion, which may imply that β-(NH4 )2SO4 and β- (N H4 ) 2 S2 O8 are different in the deactivating routes.