The influence of solvent composition on the rates of second-order nucleophilic substitution reactions in alcohol–water mixtures

Abstract

The overall rates of substitution of a number of aliphatic and activated aromatic halides by various nucleophiles in alcohol–water mixtures have been measured in the region near 100% alcohol. The results, particularly the unexpected increases of rate with additions of water, are discussed in terms of three effects: the Hughes–Ingold theory of solvent action, the change of nucleophile to hydroxide in aqueous solvents, and the proposed progressive dissociation of ion-parts of the sodium salts of anionic bases in more aqueous solvents.