%0 Journal Article
%T Kinetics and Mechanism of Micellar Catalyzed Oxidation of Dextrose by N-Bromosuccinimide in H2SO4 Medium
%A Minu Singh
%J International Journal of Carbohydrate Chemistry
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/783521
%X Kinetics and mechanism of micellar catalyzed N-bromosuccinimide oxidation of dextrose in H2SO4 medium was investigated under pseudo-first-order condition temperature of 40¡ãC. The results of the reactions studied over a wide range of experimental conditions show that NBS shows a first order dependence, fractional order, on dextrose and negative fractional order dependence on sulfuric acid. The determined stoichiometric ratio was 1£¿:£¿1 (dextrose£¿:£¿N-bromosuccinimide). The variation of Hg(OAC)2 and succinimide (reaction product) has insignificant effect on reaction rate. Effects of surfactants, added acrylonitrile, added salts, and solvent composition variation have been studied. The Arrhenius activation energy and other thermodynamic activation parameters are evaluated. The rate law has been derived on the basis of obtained data. A plausible mechanism has been proposed from the results of kinetic studies, reaction stoichiometry, and product analysis. The role of anionic and nonionic micelle was best explained by the Berezin¡¯s model. 1. Introduction The kinetics of oxidation of sugars has been a subject of extensive research in recent years. The biological as well as the economic importance of carbohydrates is responsible for the great interest in the study of their bio- and physicochemical properties. The versatile nature of N-halomides due to their ability to produce halonium cations, hypohalite species, and nitrogen anion, which act as both bases and nucleophiles [1]. N-haloamides, well known as N-bromosuccinimide, is a very important member of this class of compounds and has received a considerable attention as an oxidizing agent for a wide range of functional groups in both acidic and alkaline media [2¨C4]. Dextrose is regarded as a representative reducing sugar and is also carbohydrate unit of nucleic acids. These carbohydrate units play important role in mammalian food supply and metabolism. Therefore, interaction of these carbohydrates with metal complexes has been subject of numerous investigations. Monosaccharides are the major source of fuel for metabolism, being used both as an energy source (glucose being the most important in nature) and in biosynthesis (Scheme 1). Scheme 1: Species of glucose (dextrose). This study helps to understand the catalytic activity of surfactants along with oxidative capacity of NBS in acidic medium. Kinetic studies of oxidation of different types of organic substrate by NBS have also been investigated by various researchers [5¨C11] to explore the effect of the substituent on the redox activity of NBS. In the search
%U http://www.hindawi.com/journals/ijcc/2014/783521/