硅改性ZSM－5沸石分子筛的酸性、孔径和择形催化性能的研究

STUDY ON THE ACIDITY,MICROPORE SIZE AND CATALYTIC SELECTIVITY OF SILICON MODIFIED ZSM-5 ZEOLITE

在不同条件下用各种硅改性剂对ＺＳＭ－５沸石分子筛进行改性，并将其用于催化乙苯歧化生成对二乙苯的反应。实验结果表明，在合适条件下用ＳｉＣｌ＿４对ＺＳＭ－５改性后，可以获得高性能形选催化剂。硅改性可以有效地消除催化剂外表面酸中心，并能对分子筛孔道进行微调。根据反应结果和反应物在催化剂中的扩散系数判断，当改性后催化剂的孔道半径与ＮａＺＳＭ－Ｓ沸石孔道半径相近时，其催化选择性最佳。

Modification by SiCl_4,CH_3SiCl_3and(CH_3)_2SiCl_2 of ZSM-5 zeolite under di-fferent conditions and the performance of the zeolites in catalyzing ethybenzene dispropor-tionation were studied.The results showed that ZSM-5 zeolite modified by SiCl_4 underproper conditions can catalyze ethylbenzene disproportionation to form high purity para-di-ethylbenzene, External surface acid sites of ZSM-5 can be eliminated and micropore size canbe adjusted when ZSM-5 zeolite is modified by SiCl_4.Disproportionation results on the zeo-lites and diffusivity measurements of the reactant showed that when the micropore size ofHZSM-5 zcolite was adjusted to the same size that of NaZSM-5,it would be a good cata-lyst to catalyze ethylbenzene disproportionation to form pure para-diethylbenzene.