Kinetics and Mechanism of Oxidation of 5-Sulfosalicylic Acid by Ditelluratocuprate(III) in Alkaline Medium

Abstract

The kinetics of oxidation of 5-sulfosalicylic acid by ditelluratocuprate(III) (DTC) has been studied spectrophotometrically between 283.2 and 303.2 K in alkaline liquids. The reaction rate showed first order dependence in ditelluratocuprate(III) and fractional order in 5-sulfosalicylic acid. It was shown that the pseudo-first order rate constant kobs increased with an increase in concentration of OH^– and a decrease in concentration of TeO₄^2-. There is a negative salt effect. A plausible mechanism of reaction involving a pre-equilibrium of adduct formation between the complex and 5-sulfosalicylic acid was proposed. The rate equations derived from mechanism can explain all experimental phenomena. The activation parameters of the rate-determining step have also been computed.