Solvent po larity, hydrogen-b onding and solvophobicity eff ects on the nucleophilic substituti on of benzenesulfonyl chloride with ani line in aqueous and non-aqueous solutions of methanol

It is genera lly accepte d that solve nt characteristics such as dipole moment, permittivity, refr active index, cohes ive pressure and polarizability are important in the rate and mecha nism of chemical reactions [۱]. The solvent effect on a typical property is described by a general correlation model which gives a simultaneous separate calculation of the contributions of non-specific solute – so lvent interactions and specific solute – solvent interactions [۲].In this pap er, the reaction of aniline with b enzenesulfo nyl chloride in methanol-ethyl acetate, methanol-wa ter and m ethanol-prop an-۲-ol mi xtures has been studied. We mad e an attem pt to investigate the use of the linear free energy rel ationship correlations LFERs to establish the r ole of solvent in reaction rates [۳].Experimental section The reaction of benzenesulfonyl c hloride with aniline was followed c onductometrically by running the reaction in the therm ostated cell at ۲۵°C. Kinetic investigations wer e carried ou t at various mole fractions of methanol in ethyl acetate, propan-۲- ol and water. The conc entrations o f benzenesul fonyl c hloride and aniline wer e ۶.۵×۱۰-۵ and ۰.۱ – ۰.۰۱ M, resp ectively, i.e. the reactio n was carried out u nder pseud o-first-order conditions. All rate determinations were carried out at least in duplicate and a veraged rat e coefficients were utiliz ed.