CHARACTERIZATION OF POROUS SILICA-GELS PREPARED VIA THE SOL-GEL PROCESS BY SI-29 CP/MAS SOLID-STATE NMR-SPECTROSCOPY

被引：34

作者：

WALTHER, KL ^{[1
]}

WOKAUN, A ^{[1
]}

BAIKER, A ^{[1
]}

机构：

[1] SWISS FED INST TECHNOL,DEPT IND & ENGN CHEM,CH-8092 ZURICH,SWITZERLAND

来源：

MOLECULAR PHYSICS | 1990年 / 71卷 / 04期

关键词：

D O I：

10.1080/00268979000102101

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：

The structure of silica gels prepared by acid or basic hydrolysis of Si(OC2H5)4 has been investigated by29Si MAS-NMR. The influence of hydrolysis conditions (pH) and drying temperature is studied by determining the percentages of Si04 local coordination units with two, three and four covalent bonds to neighbouring silica centres. Further information is obtained by monitoring the H-29Si cross-polarization dynamics; an oscillatory component of the magnetization transfer is observed. The cross-relaxation rate lJrsiH and the spin-diifusion rate lJrHH are discussed in terms of current models of the sol-gel process, in which the structure of the resulting gel is influenced by the kinetics of both the hydrolysis and subsequent condensation reactions. © 1990 Taylor & Francis Group, LLC.

引用

页码：769 / 780

页数：12

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