Influence of CTAB and SDS on the Oxidation of Leucine by Quinolinium Dichromate in Presence of HClO4

The effect of cationic surfactant, cetyltrimethylammonium bromide (CTAB) and anionic surfactant, Sodium dodecyl sulfate (SDS) on the chromic acid oxidation of L–Leucine in perchloric acid medium at a constant ionic strength of 3.25 mol dm–3 and at 35°С have been investigated spectrophotometrically. The reaction exhibits a 3 : 2 stoichiometry (Leucine: Quinoline Dichromate). The reaction shows first order dependence on oxidant Quinoline Dichromate, fractional first order on Leucine and Acid. The final products of oxidation of leucine were identified as the corresponding aldehyde Isopentaldehyde (3-methylbutyraldehyde), ammonium ion and carbon dioxide. The rate of reaction increased with the increase in dielectric constant of the medium. Both the surfactants, cetyltrimethylammonium bromide and Sodium dodecyl sulfate catalyze the reaction, however the effect of anionic surfactant is pronounced than cationic surfactant. Critical Micellar Concentration (CMC) of SDS and CTAB in aqueous solutions and amino aqueous solutions have been determined and thermodynamic parameters of micellization were also evaluated in both presence and absence of amino acid.