Kinetics of oxidation of oxalic and malonic acids by trichloroisocyanuric acid

The kinetics of oxidation of oxalic and malonic acids by trichloroisocyanuric acid in aqueous acetic acid-perchloric acid mixtures has been studied. The reactions are first order in oxidant and in substrate in both the cases. The reaction with oxalic acid exhibited an inverse unit dependence on H+ whereas with malonic acid it was insensitive to acid in the concentration range studied. The solvent effect also exhibited diversity. The reaction with oxalic acid was retarded by the increase in acetic acid composition whereas with malonic acid there was an increase in kinetic rate with increase in the percentage of acetic acid. Mn(II) also showed a different behaviour: oxalic acid was insensitive to [Mn(II)] whereas there was catalysis with malonic acid on the addition of Mn(II). Addition of halide ions also exhibited completely different behaviour. Cl- did not enhance the rate and I- retarded the reaction enormously in the case of oxalic acid whereas both Cl- and I- increased the kinetic rate of the oxidation of malonic acid. The Arrhenius parameters have been evaluated.