Effect of CTAB Micellar Medium on Cu(II) Catalyzed L-Leucine Oxidation by Hexacyanoferrate(III)

Abstract

The proposed study aimed to explore the kinetics of L-leucine (Leu) oxidation in a micellar media of cetyltrimethylammonium bromide (CTAB) by hexacyanoferrate(III) {HCF(III)}. The reduction in absorbance at 420 nm, which is indicative of the concentration of HCF(III), was measured to determine the reaction rate. Applying the pseudo-first-order state, The reaction’s progression was analyzed as an indicator of [HCF(III)], temperature, [Leu], [Cu(II)], [CTAB], ionic strength, and [OH^–]. The findings indicate that the [CTAB] is the crucial factor that significantly affects the rate of the reaction. The HCF(III) undergoes a 2 : 1 stoichiometric interaction with Leu and has a first-order reliance on [HCF(III)]. The observed reaction exhibits fractional-first-order kinetics with regards to [Leu], [OH^–], and Cu(II), within the range of concentrations investigated. The observed linear augmentation in reaction rate upon electrolyte’s introduction is suggestive of a positive salt effect. The inclusion of CTAB substantially enhances the catalytic activity of the process. After reaching its maximum rate, the reaction exhibits a very steady behavior even when the [CTAB] is further increased. The observed decrease in CTAB CMC could potentially be attributed to the diminished electrostatic repulsion among the cationic surfactant head groups, which is caused by the anionic [Cu(OH)₄]^2–, OH^–, and HCF(III) species.