Kinetics and mechanism of the oxidation of aliphatic diamines by peroxodisulphate

The kinetics of the oxidation of two aliphatic diamines (1,2-diaminoethane and 1,3-diaminopropane) with potassium peroxodisulphate in aqueous medium were investigated under identical conditions. The rates of the uncatalysed reactions were not influenced by changing the ionic strength or by the presence of allyl acetate. An analysis of the dependence of the rates of oxidation shows that the reactions are second order, being first order in both diamine and peroxodisulphate ion. Activation parameters for uncatalysed reactions were reported. The catalytic effect of the cations Cu²⁺ and Ag⁺ on the rate of oxidation of diamines is compared. On the basis of kinetic studies and product analysis the rate laws and reaction mechanisms for both uncatalysed and silver-ion catalysed reactions are proposed.