Solvent effects on the kinetics of alkaline hydrolysis of dimethylacetylacetone. Part II. Influence of dipolar aprotic solvent–water mixtures

Abstract

The influence of a few protic–dipolar aprotic mixtures on the kinetics of alkaline cleavage of dimethylacetylacetone has been studied. The aprotic components used are dimethyl sulphoxide, acetone, dioxan, sulpholan, dimethoxyethane, and hexamethylphosphoramide. In most of these mixtures, the behaviour of the reaction is very analogous with that of alkaline hydrolysis of esters which suggests an identical mechanism for both reactions. Moreover the determination of activation parameters in dimethyl sulphoxide–water mixtures enables one to discuss the part played by the substrate on the reaction rate. Finally, kinetic results which are similar for some media can be explained by their nearly identical basicity.