Effects of preferential solvation and of solvent–solvent interaction on the rates of nucleophilic substitution involving anions in binary mixed solvents. Theoretical approach

Abstract

Theoretical procedures for investigating rate constants and activation parameters measured in binary mixed solvents have been presented on the basis of the concept of ideal associated mixtures. In methanol + acetonitrile mixtures the behaviour of the rate constant and of activation parameters for the ethyl iodide plus bromide ion reaction were interpreted as resulting from the specific interaction of bromide ion with methanol. In methanol +N N-dimethylacetamide mixtures association complex formation between methanol and N N-dimethylacetamide makes a significant contribution to the activation parameters, and this factor must be taken into account in interpreting the observed rate behaviour.