Solvolysis rates in aqueous–organic mixed solvents. Part 4. Kinetics of the alkaline decarboxylation of trichloroacetate ion in water–methanol solutions

Abstract

The kinetics of the alkaline decarboxylation of trichloroacetate ion in water-methanol solutions covering the whole composition range have been studied over the temperature range 30.0–52.0 °C. The results indicate that the rate of reaction is independent of the concentration of the solvoxide ion and point to a mechanism in which the rate-determining step is formation of CCl₃^– carbanion. The rate of reaction varies with methanol concentration in the mixed solvent in a non-linear manner. The activation parameters, ΔH^‡ and ΔS^‡, showed a minimum at a water : methanol mole ratio of ca. 3:2.