ZSM-5沸石中非骨架铝对沸石裂化性能影响的初步探讨

EFFECT OF EXTRA FRAMEWORK ALUMINIUM IN ZEOLITE ZSM 5 ON ITS CRACKING PROPERTIES

用固体核磁共振和红外光谱等手段，研究了ＺＳＭ－５沸石经水热焙烧产生的非骨架铝对沸石结构性能和催化性能的影响。结果表明，水热焙烧产生的非骨架铝通过氟硅酸洗涤可部分除去；非骨架铝既存在于沸石内表面，也存在于沸石的外表面，覆盖了沸石的部分酸性中心。同时，用脉冲微反及轻油微反考察了非骨架铝对沸石裂化性能的影响。结果表明，非骨架铝的存在使沸石的裂化活性降低，但烯烃选择性增高。说明沸石中非骨架铝对提高沸石烯烃选择性是有利的。因此，在制备裂化催化剂时，适当调整沸石中非骨架铝与骨架铝的比例是很重要的。

The effect of extra framework aluminium(EFA)in ZSM 5 produced by hydrothemal treatment on zeolite structure and catalyst performance was studied by NMR and IR.The results showed that EFA existing not only on the inner surface of zeolite,but also on its outer surface can screen part of acid sites of zeolite,and can be washed off by fluosilicicacid(H 2SiF 6).The result also showed that the presence of EFA decrease activity and increase olefin selectivity of zeolite,so it is important to adjust the ratio of EFA/FA in producing zeolite.