Theoretical Prediction of Thermal Diffusion in Water–Methanol, Water–Ethanol, and Water–Isopropanol Mixtures using the PC-SAFT Equation of State

In this paper, by combining the PC-SAFT equation of state (EOS) to the thermal diffusion models for non-associating mixtures, the theoretical prediction of thermal diffusion has been carried out for associating fluid mixtures including water–methanol, water–ethanol, and water–isopropanol. At first, the parameters of the PC-SAFT for water–methanol, water–ethanol, and water–isopropanol mixtures are optimized. Then, by comparing the predictive and experimental values of density and residual partial molar enthalpy in water–methanol, water–ethanol, and water–isopropanol mixtures, we demonstrate the capability of PC-SAFT EOS to reproduce reliable thermodynamic properties in these mixtures with a low to moderate water concentration. Finally, with the thermodynamic properties from the PC-SAFT, several thermal diffusion models available in the literature are extended to binary water–alcohol mixtures including water–methanol, water–ethanol, and water–isopropanol. The Firoozabadi model combined with the PC-SAFT EOS has shown an effective capability for predicting mixtures with a low to moderate water concentration.