Réactions dans le sulfolane. II. Etude électrochimique de systèmes oxydo-réducteurs des halogènes

Abstract

The electrochemical oxidation of halides and reduction of halogens have been studied in sulfolane, an aprotic solvent. Stable trihalide ions X3− are formed. The formation constants K of these X3− ions have been determined by potentiometry as 107.4 (X = I), 106.8 (X = Br), and 1031(X = Cl) in a 0.1 M LiClO4 medium. The values of the constants K have also been obtained in methanol, a hydroxylic solvent, 104.2 (X = I), 102.3 (X = Br), and in mixtures of both solvents (X = I). The variations of solvation energies of X3− and X− ions from one solvent to the other were estimated by means of a ferrocene electrode.