Modeling Interfacial Tension of Hexane + Alcohol Mixtures at Different Temperatures Using Linear Gradient Theory with Cubic Plus Association Equation of State

This work has been dedicated to modeling the interfacial tension of hexane + alcohol mixtures in the temperature range of 283.15 K to 313.15 K. The cubic plus association equation of state is applied to the liquid–vapor phase equilibrium calculations. The binary interaction parameters are obtained according to the experimental phase equilibrium data. The linear gradient theory is used as a predictive and adjustment approach to describe the interfacial tension of hexane + alcohol mixtures. The influence parameters of the pure components were correlated with the temperature and the symmetric parameters were correlated with the temperature and with the carbon number of the alcohol. The results of this work show that the equation of state used is capable of simultaneously representing the phase equilibrium and interfacial tension of the mixtures studied. Despite using the simplified version of the gradient theory, the results obtained in the interfacial tension are in agreement with those published in the literature.