Solvolysis of Sulphonyl Halides. III. The Hydrolysis of Methane- and Ethanesulphonyl Chlorides in Aqueous Dioxan and Aqueous Acetone

Abstract

The hydrolyses of methane- and ethanesulphonyl chlorides in aqueous acetone and aqueous dioxan, in the range 0.2-1.0 mole fraction of water, follow an SN2 mechanism. The first-order rate constants at low temperature go through a maximum as the composition of the solvent approaches pure water and there is a marked retardation at other temperatures. There is strong evidence that the nature of the transition complex is changing as the solvent composition is changed. The data arising from the use of an extended range of solvent composition have invalidated earlier discussions of the nature of this reaction.