Structural Insights into Aluminum Chlorofluoride (ACF)
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- 作者：Thoralf Krahl ; Reinhard Stö ; sser ; Erhard Kemnitz ; Gudrun Scholz ; Michael Feist ; Gilles Silly ; and Jean-Yves Buzaré
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：October 6, 2003
- 年：2003
- 卷：42
- 期：20
- 页码：6474 - 6483
- 全文大小：182K
- 年卷期：v.42,no.20(October 6, 2003)
- ISSN：1520-510X
文摘
The structure of the very strong solid Lewis acid aluminum chlorofluoride (ACF, AlClxF3-x, x = 0.05-0.3) wasstudied by IR, ESR, Cl K XANES, 19F MAS NMR, and 27Al SATRAS NMR spectroscopic methods and comparedwith amorphous aluminum fluoride conventionally prepared by dehydration of 
-AlF3·3H2O. The thermal behaviorof both compounds was investigated by DTA and XRD. In comparison to ACF, amorphous AlF3 prepared in aconventional way is not catalytically active for the isomerization reaction of 1,2-dibromohexafluoropropane, whichrequires a very strong Lewis acid. Both compounds are mainly built up of corner-sharing AlF6 octahedra forminga random network. The degree of disorder in ACF is higher than in amorphous AlF3. Terminal fluorine atoms weredetected in ACF by 19F NMR. The chlorine in ACF does not exist as a separate, crystalline AlCl3 phase. Additionally,chlorine-containing radicals, remaining from the synthesis, are trapped in cavities of ACF. These radicals are stableat room temperature but do not take part in the catalytic reaction.
-AlF3·3H2O. The thermal behaviorof both compounds was investigated by DTA and XRD. In comparison to ACF, amorphous AlF3 prepared in aconventional way is not catalytically active for the isomerization reaction of 1,2-dibromohexafluoropropane, whichrequires a very strong Lewis acid. Both compounds are mainly built up of corner-sharing AlF6 octahedra forminga random network. The degree of disorder in ACF is higher than in amorphous AlF3. Terminal fluorine atoms weredetected in ACF by 19F NMR. The chlorine in ACF does not exist as a separate, crystalline AlCl3 phase. Additionally,chlorine-containing radicals, remaining from the synthesis, are trapped in cavities of ACF. These radicals are stableat room temperature but do not take part in the catalytic reaction.