Kinetic Study of Oxidation of Valine by N-bromophthalimide in Presence of Iridium (III) Chloride as Homogenous Catalyst

Abstract

The mechanistic study of Ir(III) chloride catalyzed oxidation of Val has been studied by by N-bromophthalimide (NBP) in aqueous perchloric acid medium at 303 K. The reaction followed first order kinetics with respect to [NBP] and zero order kinetics with respect to [Val]. At lower concentration range of Ir(III) chloride, the reaction followed first order kinetics while tending to zero order at its higher concentration. A negative effect was observed for [H⁺] and [NHP] (phthalimide) whereas variation in [Hg(OAc)₂] (mercuric acetate), [Cl⁻], 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 used to calculate the activation parameters. A plausible mechanism from the results of kinetic studies, reaction stoichiometry and product analysis has been proposed.

Keywords:

• Ir(III) chloride
• kinetics
• NBP
• oxidation
• valine