Oxidation of Valine by N-Bromophthalimide in Presence of Chloro-Complex of Pd(II) as Homogenous Catalyst: A Kinetic and Mechanistic Study

Abstract

Kinetics of Pd(II) catalyzed oxidation of valine has been studied by N-bromophthalimide (NBP) in acidic medium at 303 K. The reaction follows first order kinetics with respect to [Pd(II)] while negative effect was observed for the variation of [H + ] on the rate of reaction. The reaction exhibits first order kinetics with respect to [NBP] at its lower concentrations and tends towards zero order at its higher concentrations. Rate of reaction exhibits zero order and fractional order kinetics with respect to [valine] and [Cl -] respectively. [Hg(OAc) 2 ], [phthalimide], ionic strength (I) and dielectric constant of the medium did not bring about any significant change on the rate of reaction. The rate constants observed at five different temperatures (298 K-318 K) were utilized to calculate the activation parameters. A plausible mechanism has been proposed from the results of kinetic studies, reaction stoichiometry and product analysis.