Kinetics and mechanism of oxidation of Cr(II) ions by tetrachloromethane

Abstract

Kinetics of the redox reaction of Cr(II) ions with tetrachloromethane has been studied in H₂O-CH₃OH-HClO₄ and H₂O-CH₃COOH-HClO₄. In the redox reaction 2 moles of Cr(II) are consumed per one mol of CCl₄, and CrCl²⁺ and CrCCL²⁺₃ ions are formed in the same amounts. Second order rate constants (k²⁹³ = 2.31 mol^-1 s ^-1 in 50% CH₃OH, k²⁹³ = 1.66 l . mol^-1 s^-1 in 50% CH₃COOH) are independent of H⁺ ions concentration.The rate determining step is an inner sphere transfer of the halogen from CCl₄ to Cr(II), the Cr-Cl-C bridge structure being retained in both media.