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[S₂O₈^2–]//_dt=kK_h[Cu^II]²//_Kh+[H+]K_h 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 Mn^II and Cl- are without any effect in contrast with the other copper-catalysed peroxydisulphate oxidations. Perhaps several hydrazine complexes of Cu^II 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.