The reactivity and microscopic polarity studies in the sodium dodecyl sulfate based reversed micellar system

The catalytic effect of the sodium dodecyl sulfate-alcohol-water reversed micellar system on the basic hydrolysis of O-ethyl-O-p-nitrophenylethylphosphonate has been studied when varying the nature of oil phase and the component ratio. To test the micropolarity in the reaction site, the solvatochromic behavior of the 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinium)phenoxide reagent has been examined in conditions analogous to those in the kinetic study. The values of the empirical parameter ET (kcal/mol) have also been calculated. The ET parameter and reactivity are found to depend on the nature and content of alcohol and on the surfactant and water concentration. The comparative analysis of kinetic data and the ET values have shown that an increase in the polarity of the microenvironment of the reagents results in the decrease in their reactivity. A quantitative treatment of kinetic data in terms of the pseudophase model confirmed a considerable contribution of the microenvironmental factor to the above catalytic effect.