Copper-catalysed oxidation of hydrazine by peroxydisulphate in acid solution

Abstract

The copper-catalysed oxidation of hydrazine by peroxydisulphate in acid solution follows the rate law (i) where –d[S2O82–]//dt=kKh[CuII]2//Kh+[H+]Kh is the hydrolysis constant of Cu2+, k was found to be 8·8 ± 0·8 min.–1, 13·1 ± 1·4 min.–1, and 17·2 ± 1·3 min.–1 at 35·40, and 45° C respectively and µ= 0·2M. The composition of the activated complex is Cu2+, CuOH+,N2H4.H+ or2Cu2+,N2H4. Allyl acetate inhibits the reaction and MnII and Cl- are without any effect in contrast with the other copper-catalysed peroxydisulphate oxidations. Perhaps several hydrazine complexes of CuII participate in the reaction and one of them isolated was Cu(N2H4)2. (HSO4)2. An oxidation study of this complex also was in conformity with the above rate law and the rate constants in the two cases were comparable.