A time resolved, in-situ X-ray diffraction study of the de-intercalation of anions and lithium cations from [LiAl2(OH)6]nX·qH2O (X = Cl−, Br−, NO3−, SO42−)

Konstantin A. Tarasov; Vitaly P. Isupov; Lyudmila E. Chupakhina; Dermot O'Hare

doi:10.1039/B314473A

A time resolved, in-situX-ray diffraction study of the de-intercalation of anions and lithium cations from [LiAl₂(OH)₆]_nX·qH₂O (X = Cl⁻, Br⁻, NO₃⁻, SO₄²⁻)

Konstantin A. Tarasov,^a Vitaly P. Isupov,^a Lyudmila E. Chupakhina^a and Dermot O'Hare*^b

* Corresponding authors

^a Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of Russian Academy of Science, Kutateladze 18, Novosibirsk, Russia

^b Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, UK

Abstract

The layered double hydroxides (LDHs), [LiAl₂(OH)₆]_nX·qH₂O (Xⁿ⁻ = Cl⁻, Br⁻, NO₃⁻, SO₄²⁻) spontaneously lose both Li⁺ cations and Xⁿ⁻ anions to give crystalline Al(OH)₃ on stirring in water. The kinetics of this topochemical de-intercalation reaction have been studied using time-resolved, in-situ energy dispersive X-ray powder diffraction. The temperature dependence of the rate of the de-intercalation reaction yields activation energies of 94 ± 15 kJ mol⁻¹ for mono-dispersed [LiAl₂(OH)₆]Cl·1.5H₂O crystallites (particle size 5–10 µm) and 117 ± 15 kJ mol⁻¹ for poly-dispersed [LiAl₂(OH)₆]Cl·1.5H₂O crystallites (particle size 1–30 µm). The rate of ion de-intercalation was found to decrease as the H₂O/LDH ratio decreased. The rate of the de-intercalation has also been shown to be dependent on the interlayer anion, with the reaction rates NO₃⁻ > Cl ⁻ > Br⁻. In the case of SO₄²⁻ rapid de-intercalation only goes to 40% completion.

$Graphical abstract: A time resolved, in-situ X-ray diffraction study of the de-intercalation of anions and lithium cations from [LiAl2(OH)6]nX·qH2O (X = Cl−, Br−, NO3−, SO42−)$

Article information

https://doi.org/10.1039/B314473A

Article type

Paper

Submitted

11 Nov 2003

Accepted

25 Feb 2004

First published

24 Mar 2004

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J. Mater. Chem., 2004,14, 1443-1447

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A time resolved, in-situ X-ray diffraction study of the de-intercalation of anions and lithium cations from [LiAl₂(OH)₆]_nX·qH₂O (X = Cl⁻, Br⁻, NO₃⁻, SO₄²⁻)

K. A. Tarasov, V. P. Isupov, L. E. Chupakhina and D. O'Hare, J. Mater. Chem., 2004, 14, 1443 DOI: 10.1039/B314473A

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Journal of Materials Chemistry