The kinetics of oxidation of five amines viz., ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), aminoethylpiperazine (AEP) and isophoronediamine (IPDA) by sodium N-chloro-p-toluenesulfonamide or chloramine-T (CAT) in the presence of HCl and Ru(III) chloride was studied at 303 K. The five reactions followed identical kinetics and the experimental rate law is rate
where x, y and z are fractions. A variation of the ionic strength or dielectric constant of the medium and the addition of halide ions and ptoluenesulfonamide had no significant effect on the rate of the reaction. The solvent isotope effect has been studied in D 2 O medium. The activation parameters have been evaluated from the Arrhenius plots. Under comparable experimental conditions, the rate of oxidation of amines increases in the order: AEP > TETA > DETA > EDA > IPDA. An isokinetic relationship is observed with Ξ² = 377 K, indicating enthalpy as a controlling factor.
Oxidation products were identified. CH 3 C 6 H 4 SO 2 + NH 2 Cl of the oxidant has been postulated as the reactive oxidizing species. Further, the kinetics of Ru(III)-catalysed oxidation of these amines have been compared with unanalyzed reactions (in the absence of Ru(III) catalyst) and found that the catalysed reactions are 2-3-fold faster. The catalytic constant (K C ) was also calculated for each amine at different temperatures from the plots of log K C against 1/T, values of activation parameters with respect to the catalyst have been evaluated. The observed results have also been explained by a plausible mechanism and the related rate law has been deduced.