Abstract
Spectrophotometric kinetic interaction of the oxidation of captopril (CPL) by hexacyanoferrate(III) (HCF(III)) in an alkaline medium has been studied spectrophotometrically. The reaction showed first-order kinetics. The rate of the reaction increased with an increase in alkali concentration. Increasing ionic strength increased the rate of the reaction. A mechanism involving the formation of a complex between CPL and HCF(III) has been proposed. The reaction constants involved in the mechanism have been evaluated. There is a good agreement between the observed and calculated rate constants under different experimental conditions. Investigations at different temperatures allowed the determination of the activation parameters with respect to the slow step of the proposed mechanism.
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