Chlorination of Phenol and p-Nitrophenol by N-Chloronicotinamide in Aqueous Acetic Acid Medium-A Kinetic and Mechanistic Study

Abstract

Kinetics of chlorination of phenol and p-nitrophenol by N-chloronicotinamide (NCN) in the presence of HClO₄ in aqueous acetic acid medium have been reported. The observed rate of oxidation is first order with respect to [N-chloronicotinamide] and [H⁺]. The order with respect to [substrate] is fractional. The rate of the reaction decreases with increase in the dielectric constant of the medium. The major product of chlorination of phenol and p-nitrophenol are 4-chlorophenol and 2-chloro 4-nitrophenol, respectively. Arrhenius and activation parameters have been calculated. A suitable mechanism has been proposed and a rate law explaining the experimental results is derived.