Kinetics and Mechanism of Nucleophilic Substitution Reaction of 4-Substituted-2,6-dinitrochlorobenzene with Benzylamines in MeOH-MeCN Mixtures

Abstract

The reaction rates of 4-X-2,6-dinitrochlorobenzenes (X = NO2, CN, CF3) with Y-substituted benzylammes (Y = p-OCH3, p-CH3, H,p-Cl) in MeOH-MeCN mixtures were measured by conductometry at 25 degrees C It was observed that the rate constant increased in the order of X = NO2>CN>CF3 and in the order of Y = p-OCH3>p-CH3>H>p-Cl When the solvent composition was varied, the rate constant increased in the order of 100% MeOH <50% (v/v) MeOH-MeCN < 100% MeCN These results may be ascribed to the formation of hydrogen bonds between the alcoholic hydrogen and nitrogen of benzylammes in groud state (GS) We conclude that the reaction takes place via SNAr base on the transition state parameters rho x, rho y, beta(nuc), and solvent effects