Oxidation of some primary amines by bromamine-B in alkaline medium: A kinetic and mechanistic study

Abstract

The kinetics of oxidation of the aliphatic primary amines, n-propylamine, n-butylamine, and isoamylamine, by sodium N-bromobenzenesulfonamide or bromamine-B (BAB) in sodium hydroxide medium has been studied at 35° C. The reaction rate shows a first-order dependence each on [BAB] and [amine], and fractional order on [OH-]. Additions of halide ions and the reduction product of BAB (benzenesulfonamide), and variation of ionic strength and dielectric constant of the medium do not have any significant effect on the reaction rate. Activation parameters have been evaluated. A Taft linear free-energy relationship is observed for the reaction with ρ* = −3.0 and δ = − 2.0 indicating that electron-donating groups enhance the rate. An isokinetic relationship is observed with β = 393 K indicating that enthalpy factors control the rate. The existence of the relationship has been supported by the Exner criterion. Mechanisms consistent with the observed kinetic data have been proposed. © 1996 John Wiley & Sons, Inc.