Effect of Cationic Micelle on the Kinetics of Oxidation of Citric Acid by N-Bromophthalimide in Acidic Medium

Potential application of Micellar nanoreactor for electron transfer reactions mediated by a variety of oxidants: A review

Surfactant, either natural or synthetic, forms a different type of aggregates among which 'Micelle' is truly an important dynamic surfactant aggregate, having a different region to interact with several organic, inorganic, and biomolecules; therefore the practical use of micelle is rapidly growing day-to-day. Surfactant-micelle, looks like a reactor of nano-dimension, govern a variety of reactions in aqueous media extensively. Oxidation is one of the vital reaction, take a part in the course of several organic transformations which are not very easy to execute in water media alone due to the solubility problem. Moreover, in order to achieve a quick transformation overcoming several difficulties the utility of micellar media became an excellent innovation, that's why nowadays, the surfactant and its aggregates are a focus of interest to the researcher of synthetic field and thus its practical applicability has been tremendously cultivated over the few decades. It is, therefore, useful to introduce some basic concepts regarding the aggregation of surfactants. Subsequently, we emphasize the importance of micellar media on the kinetics of oxidation reactions mediated by several metal ions with a special emphasis on their catalytic role.

Effect of Surfactants on Hydrolysis of Mono-N-ethyl-o-toluidine Phosphate

Hydrolysis of phosphate ester (Mono-N-ethyl-o-toluidine phosphate) in the presence of different surfactants has been studied at 303 K. The rate of reaction has been found to be first-order and fractional order kinetics with respect to [substrate] and [HCl] respectively. The cationic micelles of cetyltrimethylammonium bromide (CTAB), anionic micelles of sodium dodecyl sulfate (SDS) and nonionic micelles of Brij-35 enhanced the rate of reaction to a maximum value and thereafter, the increase in concentration of surfactant decreased the reaction rate. The rate of reaction increased with increase of dielectric constant of the medium. The variation in the rate of hydrolysis by micelles was treated by considering the Menger-Portnoy, Piszkiewicz's and Berezin kinetic models. The various thermodynamic parameters have also been evaluated. The added salts viz KCl, KNO3, K2SO4 enhanced the rate of reaction in the presence of cationic, anionic and non-ionic micelles. The kinetic parameters i. e. micellar phase (kΨ) and binding constant (KS) were determined from the rate (surfactant) profile.

Effect of Cationic Surfactant on the Oxidation of Galactose by N-Bromophthalimide in the Presence of Acidic Medium: A Kinetic and Mechanistic Study

The effect of cationic surfactant on the oxidation of galactose by N-bromophthalimide in the presence of acidic medium at 308 K has been studied. The order of reaction with respect to [Gal], [oxidant], and [H+] were found to be fractional, first, and negative fractional order, respectively. The effects of KCl, KBr, phthalimide and mercuric acetate have also been studied and summarized. The rate of reaction decreased with an increase in dielectric constant of the medium. The effect of cationic surfactant cetylpyridinium chloride (CPC) has been studied. CPC retards the rate of reaction. Thermodynamic and activation parameters have been evaluated.

Effect of CTAB Micelle on the Oxidation of L-Leucine by N-Bromophthalimide: a Kinetic Study

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 (K 1 and K 2) have been computed.