Effect of CTAB micelle on the oxidation of L-Leucine by N-Bromophthalimide: A kinetic study

Article abstract of DOI:10.1524/zpch.2011.0004

The effect of cationic surfactant cetyltrimethylammonium bromide (CTAB) on the oxidation of L-leucine by N-bromophthalimide (NBP) has been studied at 308 K. The reaction exhibits first order dependence on NBP and L-leucine and negative and fractional order dependence on HClO₄. The effects of KCl, KBr, phthalimide and mercuric acetate have also been studied and summarized. The rate of reaction increased with an increase in dielectric constant of the medium. CTAB strongly catalyzes the reaction and typical k _obs and CTAB profile was observed, i.e., with a progressive increase in CTAB, the reaction rate increased and after achieving a peak k_obs decreased at higher concentrations of CTAB. The results are treated quantitatively in terms of "Piszkiewicz" and "Raghvan and Srinivasan's" models. The various activation parameters in presence and absence of CTAB have been also evaluated. A suitable mechanism consistent with the experimental findings has been proposed. The rate constant in micellar phase k_M, cooperativity index (n), binding constant (K₁ and K₂) have been computed. by Oldenbourg Wissenschaftsverlag, Mu?nchen.