Oxidation of paracetamol by sodium N-bromobenzene sulphonamide in alkaline medium: A kinetic and mechanistic approach

The kinetics and mechanism of oxidation of paracetamol (PAM) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) have been investigated in NaOH medium at 298 K. The rate shows first order in [BAB], zero order in [PAM], and fractional order in [NaOH]. Addition reaction product, benzenesulphonamide, retards the reaction rate. The dielectric effect is positive. Variation of ionic strength of the medium and addition of halide ions have no significant effect on the rate. The solvent isotope effect was studied using D2O. The reaction fails to induce the polymerisation of acrylonitrile. Composite activation parameters for the reaction have been determined from the Arrhenius plot. Hypobromous acid (HOBr) is assumed to be the reactive oxidant species. 4-amino-2,6-dibromophenol was identified as the oxidation product of PAM. A mechanism discussed.