UNCATALYZED AND CU(II) CATALYZED O-DIASIDINE OXIDATION WITH PEROXYDISULFATE IN AQUEOUS-SOLUTION

The uncatalysed and copper ion catalysed oxidation kinetics of 3,3'-di methoxy benzidine (o-dianisidine, oda) with potassium peroxydisulphate have been studied in aqueous solutions. Uncatalysed reaction was foun d to follow second order kinetics - with first order rate dependence o n both the oxidant and reductant. In the catalysed reaction, the rate equation is first order with respect to both peroxydisulphate and copp er ions and fractional with oda, respectively. The order with respect to oda decreased with increasing concentration of catalyst. Both the r eactions. had 1 : 3 (oda peroxydisulphate) stoichiometric ratios and f or both the reactions final oxidation product was identified to be 3,3 '-dimethoxy-4,4-diphenoquinone dioxime. Reaction mechanisms and rate l aws consistent with experimental data are suggested.