KINETICS OF THE OXIDATION OF IODIDE BY PERSULFATE IN AOT-OIL-WATER MICROEMULSIONS

The oxidation of iodide by persulphate has been studied in different sodium bis-2-ethylhexylsulphosuccinate (aerosol-OT or AOT)-oil-water microemulsions at 298 K. The rate of this reaction is appreciably higher in a microemulsion than when it takes place in a conventional aqueous medium. The dependence of the rate constant on the surfactant concentration as well as on the molar ratio R(= [H2O]/[AOT]) has been examined. The results are interpreted on the basis of the anionic nature of the reactants and the surfactant itself, and the high concentrations of sodium cations inside the aqueous cores. The dependence of the rate constant on the nature of the organic phase present in the system has also been investigated.