A kinetic study of oxidation of 2‐phenylethylamine (PEA), a bioactive compound, with potent oxidant, N‐bromosuccinimide (NBS) has been carried out in HCl and NaOH media at 313 K. The experimental rate laws obtained are: ‐d [NBS] /dt = k[NBS][PEA][H+] in hydrochloric acid medium and ‐d [NBS]/dt = k[NBS][PEA]x[OH−]y in alkaline medium where x and y are less than unity. Accelerating effect of [Cl−], and retardation of the added succinimide on the reaction rate have been observed in acid medium. Variation of ionic strength of the medium shows negligible effect on rate of reaction in both media. Decrease in dielectric permittivity of the medium decreased the rate in both media. The stoichiometry of the reaction was found to be 1:1 in acid medium and 1:2 in the case of alkaline medium. The oxidation products of PEA were identified as the corresponding aldehyde and nitrile in acid and alkaline medium, respectively. The reactions were studied at different temperatures and the activation parameters have been evaluated. The reaction constants involved in the proposed mechanisms were computed. The reaction was found to be faster in alkaline medium in comparison with the acid medium, which is attributed to the involvement of different oxidizing species. The proposed mechanisms and the derived rate laws are consistent with the observed experimental results.

Metronidazole (MTZ) and tinidazole (TNZ) belong to nitroimidazole group of drugs used to treat infections such as ameobiasis, giardiasis and trichomoniasis. The kinetics of oxidation of MTZ and TNZ with N-bromosuccinimide (NBS) in perchloric acid medium has been investigated at 308 K. A 1:1 stoichiometry has been observed in both MTZ and TNZ cases. The oxidation reactions of both MTZ and TNZ follow the same rate law, -d[NBS]/dt = [NBS][Sub][H + ]. However, in case of MTZ, at higher concentrations of H + (0.006-0.01 mol dm -3 ), the rate law obtained is -d[NBS]/dt = [NBS][MTZ][H + ] -1 . Accelerating effect of [Cl -] and retardation of the added succinimide on the reaction rate have been observed in the case of MTZ. The reactions were examined with reference to changes in concentration of added neutral salt, ionic strength and dielectric permittivity of the medium. The overall activation parameters have been evaluated from the Arrhenius plot. The reactive oxidizing species of NBS have been determined. The main oxidation products were identified by IR and 1 H NMR spectral analyses. The observed results have been explained by plausible mechanisms and the relative rate laws have been deduced.

The kinetics of ruthenium (III)-catalyzed oxidative cleavage of phenylpropanolamine (2-amino-1-phenyl-propan-1-ol) (PPA) with N-bromosuccinimide (NBS) in HCl medium has been investigated at 308 K. The oxidation reaction follows the rate law, d, where a and b are less than unity. The stoichiometry of the reaction has been found to be 1:1, and benzaldehyde and acetaldehyde were identified as the oxidation products of PPA. The activation parameters have been evaluated from the Arrhenius plot. NBS itself has been postulated as the reactive oxidizing species. The observed results have been explained by plausible mechanisms and the related rate law has been deduced.