Electrogeneration, behaviour and applications of cobalt(III) in perchlorate solutions in acetic acid

Abstract

Conditions for the electrochemical generation of cobalt(III) in acetic acid—perchlorate media were determined. The current efficiency depended on the current density at the working electrode and on the amounts of water or acetic anhydride in the solution. The stability of cobaltl(III) decreased with increasing content of water and perchloric acid in the solution, but increased with increasing content of acetic anhydride. The biamperometric system with the electrodes immersed in a solution of sodium perchlorate, cobalt(II) and cobalt(III) in acetic acid, in the presence of a definite amount of water, behaved as an electrochemical oscillator. Coulometric titration methods were developed for the determination of reducing substances with cobalt(III), the end-point being detected by the biamperometric and potentiometric methods. Errors in the determinations were less than ±2%.