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Issue 10, 1986
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Kinetics of metal oxide dissolution. Oxidative dissolution of chromium(III) oxide by potassium permanganate

Abstract

A detailed study of the oxidative dissolution of chromium(III) oxide (Cr2O3) in potassium permanganate is reported. The kinetics of the reaction follow an inverse-cubic rate law under both acid and alkaline conditions; no inhibition by MnO2 product is observed. In alkaline solution, in the temperature range 43–140 °C, the rate exhibits dependences on permanganate and hydroxide concentrations which are explained in terms of a Langmuirian adsorption mechanism. The rate of dissolution is controlled by electron transfer within a surface complex in which both OH and MnO4 are bound. Thermodynamic parameters imply chemical bond formation between permanganate and ions in the oxide surface. A study in dilute HNO3 shows that adsorption of MnO4 is also a prerequisite for reaction under acid conditions.

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Article information


J. Chem. Soc., Faraday Trans. 1, 1986,82, 3245-3254
Article type
Paper

Kinetics of metal oxide dissolution. Oxidative dissolution of chromium(III) oxide by potassium permanganate

M. G. Segal and W. J. Williams, J. Chem. Soc., Faraday Trans. 1, 1986, 82, 3245
DOI: 10.1039/F19868203245

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