Rate enhancement of the Ru(III) facilitated oxidation of L-leucine by Cu(III) periodate in CPC micellar medium: a kinetic and mechanistic approach

Amino acid oxidation is fascinating because different oxidants produce diverse compounds. No research has examined how metal catalysts affect amino acid oxidation by diperiodatocuprate(III) (DPC) in micellar environments. This research is crucial to understanding amino acids in redox processes and identifying active species of Ru(III) and DPC. The present study will evaluate how cationic surfactant affects Ru(III)-facilitated L-leucine (L-Leu) oxidation utilizing DPC in an alkaline medium. The progression of the reaction has been evaluated using the pseudo-first-order scenario as a metric for [OH⁻], [DPC], ionic strength, [L-leucine], [Ru(III)], [IO₄⁻], [Surfactant], and temperature. The interaction between DPC and L-leucine occurs stoichiometrically at a ratio of 4:1. Throughout the range of concentrations analyzed, the observed reaction demonstrates a kinetic order that is less than one concerning both [OH⁻] and [L-leucine], exhibits negative fractional-order with respect to [IO₄⁻], and shows first-order dependence on [Ru(III)] and [DPC]. The consistent oxidation rate observed with the addition of electrolytes suggests a zero salt effect. Experimental results indicate that monoperiodatocuprate(III) (MPC) is the main Cu(II) species. Ru(III) enhances the oxidation rate by forming an L-Leucine-Ru(III) complex, which interacts with MPC to create a free radical intermediate which is eventually converted into a product. The oxidation rate is markedly increased by Ru(III) solution acting as a catalyst at ppm concentration. The micellar media of cetylpyridinium chloride (CPC) significantly accelerates the rate of the desired reaction, achieving an enhancement of fourfold. The compatibility of CPC with Ru(III) for the oxidation of L-leucine utilizing DPC is notably remarkable.