Hydrogen bonding and solvolysis of alkyl sulphonate esters and related compounds

Abstract

Hydrogen bonding between alkyl sulphonyl compounds andp-chlorophenol in carbon tetrachloride solution has been investigated by infra-red spectrometry. Analysis of the intensity of the bonded O-H stretching absorption indicates that, under the conditions employed, only 1:1 complexes are formed in significant concentration. Equilibrium constants for the complex formation have been determined at 15, 25, 35 and 45° C., and the corresponding enthalpy values derived. The strengths of the hydrogen bonds have been estimated from the positions of the bonded O-H stretching bands, and these frequencies correlate with the normal electronic effect of substitution in aryl and alkyl groups attached to the sulphonyl group. The rate of solvolysis of the methyl sulphonates in water is shown to vary inversely as the strength of the hydrogen bond formed. The possible bearing of these observations on certain aspects of the detailed mechanism of solvolysis is discussed.