Kinetics of Ruthenium(III) [Ru(III)] chloride catalyzed oxidation of valine (Val) has been studied by N-bromophthalimide (NBP) in the acidic medium at 35°C. The reaction rate follows first-order and zero-order dependence with respect to [NBP] and [Val]. First-order kinetics was observed for Ru(III) chloride at low range of concentrations and tending towards zero-order at higher concentrations. A negative effect was observed for [H ? ] and [phthalimide], while a positive effect was observed for [Cl -] on the reaction rate. Hg(OAc) 2 , ionic strength (I), and dielectric constant (D) of the medium did not change significantly the reaction rate. The rate constants as a function of temperature (298-318 K) were used to calculate activation parameters of the oxidation of Val by NBP. A plausible mechanism was proposed to explain the results of kinetic studies, reaction stoichiometry and product analysis.

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The kinetics of Ru(III) chloride-catalyzed oxidation of b-Alanine (NH 3 ? CH 2 CH 2 COOH, b-Ala) by Nbromophthalimide (NBP) in aqueous perchloric acid medium was studied at 35°C. The rate law followed a first-order and zero-order dependence with respect to [NBP] and [b-Ala], respectively. The reaction followed first-order kinetics with respect to [Ru(III)] chloride at a range of low concentrations while the order changed from first-to zero-order at high concentration of [Ru(III)] chloride; demonstrating the catalytic effect for the oxidation of b-Ala by NBP. The rate decreased with increase in acidity. Chloride ions positively influenced the rate of the reaction. Neither phthalimide (NHP) nor Hg(II) influenced the reaction rate. Ionic strength (I) and dielectric constant (D) of the medium had no significant effect on the rate. Activation parameters of the reactions were determined by studying the reaction at different temperatures (30-50°C). The colorimetric, FTIR, and GC-MS techniques were used to identify methyl cyanide (CH 3 CN) and CO 2 as products of the reaction. In the reaction, approximately 2.3 moles of NBP oxidized one mole of b-Ala. A reaction scheme of the oxidation of b-Ala by NBP in the presence of Ru(III) chloride was found to be in consistent with the rate law and the reaction stoichiometry.

The kinetics of oxidation of some a-hydroxy acids viz. Tartaric acid (TA) and Malic acid (MA) by Nbromophthalimide (NBP) were studied in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), in perchloric acid medium at 313 K. The oxidation of TA and MA by N-bromophthalimide in the presence of CTAB is faster than in the absence of surfactant. The rate of oxidation of hydroxy acids was found to be in the order: TA > MA. First order kinetics with respect to NBP was observed in the oxidation of both hydroxy acids. The kinetics results indicate that the first order kinetics in hydroxy acids at lower concentrations tends towards a zero order at its higher concentrations. Inverse fractional order in [H + ] and [phthalimide] were noted throughout its tenfold variation. With a progressive increase in [CTAB], the rate of reaction increased, reaches a maximum value and then constancy in k W was observed. Variation of [Hg(OAc) 2 ] and ionic strength (l) of the medium did not bring about any significant change in the rate of reaction. The applicability of different kinetic models viz. the Piszkiewicz cooperative model, the Raghvan and Srinivasan model, and the Menger-Portnoy model were tested to explain the observed micellar effects. The effect of [CTAB] on the activation parameters was explored to rationalize the micellar effect. The values of rate constants observed at four different temperatures were utilized to calculate the activation parameters. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.