Copper-catalyzed autoxidation of carbohydrazide: kinetics and mechanism

Carbohydrazide (CHZ) reduces dissolved oxygen to H 2 O 2 and probably H 2 O in the presence of Cu(II) salts at alkaline pH. Hydrazine is also produced. The rate of the reaction increases with increasing pH. The reduction is a chain reaction initiated by a transformation of the known Cu II (CHZ) 2 complex and obeys first-order kinetics, i.e., −d[O 2 ]/dt=k'[O 2 ], for a substantial portion of the reaction. The reaction is complex in that hydrazine competes with CHZ for Cu(II). In more concentrated solutions, autoxidation produces a condensation dimer, 1,2-hydrazinedicarbonic dihydrazide, and higher homologues