Compressibilités de l'eau et du benzène dans tout le domaine de miscibilité du système eau + 2-propanol + benzène

Sound velocities have been measured over the whole miscibility domain of the water + 2-propanol + benzene system. The apparent molar isentropic compressibilities of benzene and water were calculated from these data. The apparent molar compressibilities of benzene and water present large changes in the water-rich and benzene-rich regions, respectively, whereas the changes are smooth in the intermediate region. These results suggest that microtransitions similar to the formation of micelles and inverse micelles occur at the two ends of the phase diagram. The regularity of the intermediate region is consistent with a bicontinuous model of microemulsions. For the water-rich region, the compressibilities of transfer of benzene at infinite dilution, from water to water + 2-propanol mixtures, were simulated with the model of Roux and co-workers. This simulation tends to confirm that the alcohol and the benzene form mixed aggregates. Keywords: compressibility, ternary system, microemulsion, water, benzene, 2-propanol.