Phase and Interfacial behavior of the ternary system Toluene / Ethanol / Water

Abstract

Equilibrium data in ternary liquid-liquid systems is necessary for the design of extraction processes. Interfacial tension is an important parameter in mass transfer models, and therefore highly relevant in extraction. Thus, experimental measurements of these parameters are a prerequisite for the development of industrial processes. This work analyzes the interfacial behavior of the water-ethanol-toluene system by experimentally determining equilibrium tie lines and interfacial tensions at 25 °C. A total of five concentration points was analyzed. Each point was measured three times. Concentrations at equilibrium were determined using gas chromatography for ethanol and toluene, and a Karl-Fischer titrator for water content. Interfacial tensions were measured using a spinning drop tensometer. Phase densities and refractive indexes were also measured, all of them at 25 °C. The obtained equilibrium data was found to be inconsistent with previous literature data. This was probably caused by errors in the experimental method. Interfacial tension measurements were consistent with previous experiments, and it was found to decrease with ethanol content, as was expected.