Theoretical and experimental investigation of the interfacial properties in the ternary mixtures water + 1-hexanol + acetic acid and water + hexylacetate + acetic acid using density gradient theory and spinning-drop tensiometry

Abstract The importance of reliable determination of interfacial tension between fluid phases has been well recognized in chemical engineering. The purpose of this work is a detailed study whether the density gradient theory in his incompressible version in combination with the activity coefficient model, namely the NRTL-model, is capable to describe or even predict the interfacial properties of two technical important mixtures, namely water + 1-hexanol + acetic acid and water + hexylacetate + acetic acid. Particular attention is directed to the prediction of ternary interfacial properties outgoing from the influence parameter of the binary subsystems, which show liquid-liquid phase split. It could be demonstrated that the predicted interfacial tension for both investigated systems are very close to the experimental data, obtained in this study. Furthermore, it could be shown that the polarity of the phase forming components determine the selective enrichment of the solubilizing component in the interphase.