The kinetics of oxidation of N(2-hydroxyethyl)ethylenediaminetriacetatocobaltate(II) by peroxodisulfate ion in aqueous acidic solutions

Summary Peroxodisulfate ion readily oxidises Co^II-YOH [YOH =N(2-hydroxyethyl)ethylenediaminetriacetate] with the formation of an intermediate complex. The kinetics of the electron-transfer step follow the rate law: Rate = 2k_HK_H[H⁺][S₂O₈]²-[Co^II-YOH]/(1 + K_H[H⁺]) where [S₂O₈]^2– is the total peroxodisulfate concentration, k_H is the rate constant for the electron-transfer process, and K_H is the pre-equilibrium protonation constant. Activation parameters have been evaluated. The intermediate, which was identified spectrophotometrically, slowly rearranges to the quinquedentate species Co(YOH)(H₂O). The rate of this rearangement has also been measured.