Oxidation of uronic acids by manganese(III) sulfate in acid solution: A kinetic and mechanistic study

The kinetics and mechanism of oxidation of D-glucuronic acid and D-galacturonic acid by manganese(III) sulfate, in aqueous sulfuric acid solution at 30 degreesC, was followed spectrophotometrically at lambda (max) = 500 nm. A first-order dependence of the rate each on [Mn(III)] and [uronic acid] was observed. The rate is independent of the concentration of hydrogen ions and the reaction product, Mn(II). Effects of varying the dielectric constant of the medium and the addition of anions such as Cl-, F-, SO42- and ClO4- have been investigated. Activation parameters have been evaluated using Arrhenius