Comproportionation Reaction of Cu(II)/Cu(0) in Ethaline-Water Mixed Solvents

Abstract

The comproportionation reaction of Cu(II) + Cu(0) → 2Cu(I) in ethaline-water mixed solvents has been studied by means of different electrochemical techniques such as cyclic voltammetry, linear sweep voltammetry and chronopotentiometry. The cyclic voltammograms of Cu(II) show two couples of redox peaks in all mixtures, which demonstrate that the comproportionation reaction is thermodynamically favorable. In order to clarify the reaction kinetics of this heterogeneous reaction, the diffusion coefficient of Cu(II) and the rate constant of the reaction were estimated. Results show that the apparent reaction rate constant mainly depends on the diffusion of the Cu(II) species in all the mixtures. Thus, adding water into ethaline can enhance the mass transfer of Cu(II) species and increase the reaction rate.