Rate constants have been measured for the oxidation of iodide ions by persulfate both in conventional aqueous solutions with various salt concentration and in the sodium bis(2-ethylhexyl) sulfosuccinate/isooctane/water microemulsions with various molar ratios R of water to surfactant. The activity of water in the aqueous core of the W/O microemulsions has been calculated and shown to be significantly decreasing with the decrease of the size of the microreactor when R≤20. The dependence of the rate constant on activity of water and ionic strength is discussed.

Key words: MICROEMUSION, POTASSIUM PERSULFATE, IODINE OXIDE, REACTION RATE, ACTIVITY