Incorporation of Chelated Cobalt Complexes and Polyoxocations of Aluminum in Montmorillonite
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- 作者：S. Thomas ; J. A. Bertrand ; and M. L. Occelli
- 刊名：Chemistry of Materials
- 出版年：1999
- 出版时间：January 1999
- 年：1999
- 卷：11
- 期：1
- 页码：184 - 187
- 全文大小：46K
- 年卷期：v.11,no.1(January 1999)
- ISSN：1520-5002
文摘
The thermal stability of montmorillonites, expanded with solutions of Co3(H2NCH2CH2O)6](ClO4)3, can be drastically increased by introducing, together with the Co trimer,[Al13O4(OH)24(H2O)12]7+ ions that upon calcination in air at 500 
C form stable aluminaclusters. Several synthetic routes to the preparation of these bipillared interlayered clays(bi-PILC) have been studied. Best results have been obtained by first ion-exchanging theclay charge compensating Na and Ca cations with [Al13O4(OH)24(H2O)12]7+ ions followed bya second ion exchange step to replace some of the Al13 clusters in the intermediate Al-PILC with [Co3(OC2H4NH2)6]3+ ions. Elemental analysis together with powder XRD resultsindicate that PILC composition and pore height can be manipulated by washing theintermediate Al-PILC in order to hydrolyze the Al oligomers believed to occupy exchangesites on the clay silicate layers. Formation of Keggin ions seems to facilitate the back-exchange reaction with the Co trimer. Pillared materials with a Si/Co molar ratio between38.4 and 128.0 and d spacing in the 1.40-1.75 nm range stable to 500 C in air can beobtained in this way.
C form stable aluminaclusters. Several synthetic routes to the preparation of these bipillared interlayered clays(bi-PILC) have been studied. Best results have been obtained by first ion-exchanging theclay charge compensating Na and Ca cations with [Al13O4(OH)24(H2O)12]7+ ions followed bya second ion exchange step to replace some of the Al13 clusters in the intermediate Al-PILC with [Co3(OC2H4NH2)6]3+ ions. Elemental analysis together with powder XRD resultsindicate that PILC composition and pore height can be manipulated by washing theintermediate Al-PILC in order to hydrolyze the Al oligomers believed to occupy exchangesites on the clay silicate layers. Formation of Keggin ions seems to facilitate the back-exchange reaction with the Co trimer. Pillared materials with a Si/Co molar ratio between38.4 and 128.0 and d spacing in the 1.40-1.75 nm range stable to 500 C in air can beobtained in this way.