Precipitation of slightly soluble silver salts in reversed AOT micelles: Calorimetric investigation

The enthalpies of precipitation, of AgCl, Agl, Ag₂S and silver tetraphenylborate (AgTPB) in water containing reversed sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micelles as a function of the molar concentration ratio R (R=water]/AOT]) at various concentrations of AOT and reagent salts, were measured by a calorimetric technique. The molar enthalpies of precipitation are independent of the surfactant concentration but are dependent on the concentration of the reagent salts and the R value. The molar enthalpies for the same processes in bulk water are not approached even at the highest R value. Effects due to the smallness of the microcrystals and to the interactions between ions and micellar interface are discussed. In part from Doctor of Biology thesis of F. Pinio, University of Palermo, Italy.