Solvent hydrogen bonding and structural effects on nucleophilic substitution reactions. Part-1: Reaction of benzenesulphonyl chloride with anilines in benzene/2-methylpropan-2-ol-mixtures

Substitution reactions of eleven para- and meta-substituted anilines with benzenesulphonyl chloride in different mole fractions of benzene in 2-methylpropan-2-ol have been investigated conductometrically. The second order rate constants don't correlate either with pK(a) values of the anilines or with the Hammett's and its modified equations. The para-substituted anilines shows a satisfactory correlation with Charton's LDR equation and the results indicate the formation of an electron deficient transition state. The rate data correlate satisfactorily with macroscopic solvent parameters such as relative permittivity, epsilon(r), and polarity, E-T(N). Multiple correlation analysis of the rate data via Kamlet-Taft's solvatochromic parameters reveals that the solvent hydrogen bond donor property plays a dominant role in governing the reactivity.