Rate constant for the reaction of the t-butoxyl radical with Fe(II) ion

The rate of the reaction of the tert-butoxyl radical (t-BuO^√) with Fe²⁺ was measured using laser flash photolysis of methanolic solutions at room temperature. t-BuO^√ were generated by homolytic photodecomposition of di-tert-butyl peroxide. The rate constant for oxidation of Fe²⁺ with t-BuO^√ radicals was studied under pseudo-first order conditions. On the basis of competitive kinetics the quantum yield of oxidation, Φ(Fe³⁺), was determined as function of Fe²⁺ concentration by measuring the absorbance of Fe³⁺ as FeCl]²⁺ complex. By using the literature values of the rate constants of relevant competing reactions, the desired rate constant was determined to be 3.0×10⁸ M⁻¹ s⁻¹.