Two pathways of arenesulfonyl chlorides hydrolysis.: Anionic intermediates in SAN-hydrolysis of 4-nitrobenzenesulfonyl chloride

Arenesulfonyl chlorides undergo the hydrolysis in water and binary aqueous solvents along two pathways of SAN mechanism involving cyclic intermediate with pentacoordinate sulfur atom (H2O)(n)SO2(CI)Ar and through anionic intermediate HO-SO2(Cl)Ar(H2O)(n). The contribution of the process involving anionic intermediates grows C, with increasing sigma(p) constant and attained maximum value for 4-nitrobenzenesulfonyl chloride. In water and 17 water-dioxane mixtures the relation of apparent first-order rate constants and activation parameters to the molar fraction of dioxane in the mixture (0-0.25) are not monotonic, and the hydrolysis process is catalyzed by dioxane.