Xe-129 NMR study of ZSM-5 type zeolites. Effect of cationic sites

被引：5

作者：

Timonen, JT ^{[1
]}

Pakkanen, TT ^{[1
]}

机构：

[1] UNIV JOENSUU,DEPT CHEM,SF-80101 JOENSUU,FINLAND

来源：

MICROPOROUS MATERIALS | 1997年 / 8卷 / 1-2期

关键词：

Xe-129 nuclear magnetic resonance; ZSM-5; zeolite; Bronsted acid sites; ion-exchange;

D O I：

10.1016/S0927-6513(96)00058-2

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

A comprehensive Xe-129 NMR spectroscopy study on H-ZSM-5 zeolites having different aluminum contents and on cation-exchanged ZSM-5 zeolites is reported. The parent H-ZSM-5 zeolites were ion-exchanged with Group I-III metal ions (K, Ca, Sr, Ba, Al, La) to varying degrees. The chemical shift of adsorbed Xe-129 is seen to be a function of the pentasil structure of ZSM-5, of the number of free Bronsted acid sites and of the number of metal cations in the framework. Differences in the chemical shift of Xe-129 are seen between cations due to their different polarizing forces against xenon. The amount of cations has also an effect on the delta(Xe-Xe) term in Fraissard's equation that may be caused by changes in the diffusional characteristics of Xe atoms in the ZSM-5 framework.

引用

页码：57 / 62

页数：6

共 17 条

[1] THE VARIATION OF XE-129 NMR CHEMICAL-SHIFTS WITH ALUMINUM CONTENT IN ZSM-5 AND ZSM-11 ZEOLITES [J].