Study on kinetics and mechanism of copper-catalyzed oxidation of hydrazine by iron (III) in acid solution

The copper-catalyzed oxidation of hydrazine by iron(III) in acid solution follows the rate law -d[Fe(III)]/dt = kK_h[Cu(II)]²/(K_h + [H⁺]), where K_h is the hydrolysis constant of Cu²⁺, k was found to be 8.8±0.8, 13.2±1.4 and 17.5±1.3 min⁻¹ at 35, 40, and 45°C respectively and μ= 0.2 mol/L. The composition of the activated complex is Cu²⁺, CuOH⁺, N₂H₄, H⁺ or others. Perhaps several hydrazine complexes of Cu(II) participate in the reaction and one of them isolated was Cu(N₂H₄)₂(HSO₄)₂. Study on the oxidation of this complex is also in conformity with the above rate law.