Micellar Effects upon Spontaneous and Carboxylate Ion Catalyzed Hydrolyses of Benzenesulfonyl Chlorides

Article abstract of DOI:10.1021/jo00224a054

Spontaneous hydrolyses of benzenesulfonyl chlorides are inhibited by micelles of cetyltrimethylammonium chloride (CTACl), sodium dodecyl sulfate (SDS), and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB3-16).The rate constants for hydrolyses of fully bound substrates are similar in CTACl and SB3-16.The rate constants in CTACl (k⁺) and SDS (k^-) depend on the electronic effects of the 4-substituents and k⁺/k^- increases in the sequence MeO < Me < H < Br < NO2.These micellar charge effects are ascribed to changes in the extents of bond-making and -breaking in the transition state.Hydrolysis in micellized N-dodecyl-N,N-dimethylglycine (B1-12) is inhibited, but this effect is offset by nucleophilic participation by the carboxylate moiety.Electron-withdrawing substituents strongly favor nucleophilic participation and for the 4-bromo and 4-nitro derivatives second-order rate constants in zwittwerionic betaine micelles of B1-12 are similar to those for reaction with nonmicellized N,N,N-trimethylglycine in water.