KINETICS OF THE REDUCTION OF CoIII ACETATE IN ACETIC ACID

We studied, through visible spectrophotometry (470-820nm), the acetate reduction kinetics of Co(III) in acetic acid between 35°C and 80°C. We demonstrated, with the presence of a 670 nm isobestic point, two Co(III) complexes: Co(III) α and Co(III) β. Spectral deconvolution allowed access to various absorbencies and suggests the following mechanism: Co(III) α ↔ Co(III) β → Co(II) The rate constants and activation energies of the three elementary steps of the reaction were obtained. Determination of Co(III) α and Co(III) β spectra allowed Co(III) α to be identified to the Co(III)s complex already known. © 2010 Canadian Society for Chemical Engineering.