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

摘要

Substitution rcactions 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.