Measurement and modeling of high pressure density and interfacial tension of carbon dioxide plus tetrahydrofuran mixture

We report experimental interfacial tension, coexisting densities and relative Gibbs adsorption measurements for carbon dioxide + tetrahydrofuran mixture in the vapor-liquid equilibrium at 298.15 K and 353.15 K and pressure up to 12.0 MPa. Measurements are based on the use of a high-pressure pendant drop tensiometer coupled to a high-pressure densimeter. The results were compared to literature values where possible. In order to complement experimental measurements, theoretical modeling on the interfacial behavior was carried out using the Square Gradient Theory based on a Peng-Robinson equation of state. Investigating the applicability of the model to describe interfacial behavior in the mixture revealed very good agreement between calculated and experimental data, where the interfacial tension decreases as the pressure increases. In order to examine accumulation of compounds at the interface the model was applied. Thereby, peculiar adsorption effects of carbon dioxide in the liquid interface of tetrahydrofuran were observed.