Solvation Effects in Hydrolysis of 2-Toluenesulfonyl Halides in Aqueous Dioxane. Catalysis with Water Molecules in Cyclic Transition States

Abstract

The activation parameters of hydrolysis of 2-toluenesulfonyl chloride in aqueous dioxane in the range of dioxane mole fractions X2 0-0.33 were determined. As for the previously studied hydrolysis of 2-toluenesulfonyl bromide, the dependences of the activation parameters on X2 are essentially nonmonotonic, with minima in the ranges of X2 0.005-0.010 and 0.10-0.12. The kinetic data were discussed taking into account the concepts of the effect of nonelectrolyte on the water structure and the results of previous PM3 calculations of benzenesulfonyl chloride hydrolysis in the gas phase and in water clusters. A scheme of catalytic hydrolysis of sulfonyl halides with water molecules in cyclic transition states was suggested.