Abstract
The kinetics and mechanism of the oxidation of D-mannose by chromium(VI) in the absence and presence of sodium dodecyl sulfate(SDS) and polyoxylethylene t-octylphenol(TX-100) micelles have been investigated. Under pseudo-first-order conditions the reaction rate is of fractional- and first-order, respectively, in D-mannose and oxidant. The reaction is catalyzed by the micelles which is due to favourable electrostatic/thermodynamic/hydrophobic/hydrogen bonding between the reactants and anionic/nonionic micelles. From the observed kinetic data micelle-chromium(VI) binding constants(K-S) and Micelle-D-mannose binding constants(K-M) were calculated to be 86, 84 mol(-1) dm(3) and 58, 75 mol(-1) dm(3) for SDS and TX-100, respectively. The reaction is retarded by addition of inorganic salts (NaBr, LiBr, NH4Br) which is attributed to competition between salt cations and H+ from the reaction sites in the SDS micelles.