The kinetics of the oxidation of chromium(II), titanium(III), and vanadium(IV) by hydrogen peroxide and hydroxyl radicals

Abstract

The reaction rate constants of Mⁿ⁺+ H₂O₂ were measured for Mⁿ⁺= Cr^II, Ti^III, and V^IV, using the stopped-flow technique, in perchloric and sulphuric acid media. These rate constants, for T^III and V^IV were found to increase on increasing the pH in the range 0–2·5. The rate constants for the reaction of these metal ions with OH radicals were measured through competition with thiocyanate anions, using the pulse radiolysis technique. It was found that k_Mⁿ⁺+OH=(1·2 ± 0·2)× 10¹⁰, (3·0 ± 0·3)× 10⁹, and (6·4 ± 0·4)× 10⁸M^–1 s^–1 for Cr^II, Ti^III, and V^IV respectively.