MAGIC-ANGLE SPINNING NUCLEAR-MAGNETIC-RESONANCE STUDIES OF WATER-MOLECULES ADSORBED ON BRONSTED-ACID AND LEWIS-ACID SITES IN ZEOLITES AND AMORPHOUS SILICA-ALUMINAS

被引：176

作者：

HUNGER, M

FREUDE, D

PFEIFER, H

机构：

来源：

JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS | 1991年 / 87卷 / 04期

关键词：

D O I：

10.1039/ft9918700657

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

On weakly rehydrated dealuminated zeolites and amorphous silica-aluminas the presence of different types of acidic centres can be ascertained by proton magic-angle spinning nuclear magnetic resonance (H-1 MAS NMR) measurements. A H-1 NMR line at ca. 6.5 ppm is caused by water adsorption on Lewis-acid sites. The shift of the H-1 NMR line of Bronsted-acid sites (bridging OH groups) to lower field for hydrated samples can be interpreted quantitatively by a fast proton exchange between water molecules, bridging OH groups and hydroxonium ions.

引用

页码：657 / 662

页数：6

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