APPLICATION OF THE PSEUDOPHASE ION-EXCHANGE MODEL TO KINETICS IN MICROEMULSIONS OF ANIONIC DETERGENTS

The acid-catalyzed hydrolysis of 2-(p-methoxyphenyl)-1,3-dioxolane has been studied in microemulsions of 1-butanol, sodium dodecyl sulfate (SDS), water, and toluene. The kinetic data was interpreted with the pseudophase ion-exchange (PPIE) formalism considering the microemulsions as a system formed by three phases (oil, water, and interphase), the degree of dissociation of the detergent being considered variable. The rate constant at the interphase is about the same as in water (k2,w = 11.6 M-1 s-1) and about 3.5 times larger than in micelles, indicating that similar to micellar systems the catalytic power of microemulsions consists of concentrating the reactive partners at the charged interphase. © 1990 American Chemical Society.