The group contribution method (GC) versus the critical point-based approach (CP): Predicting thermodynamic properties of weakly- and non-associated oxygenated compounds by GC-PPC-SAFT and CP-PC-SAFT

In this study GC-PPC-SAFT and the CP-PC-SAFT Equations of State have been implemented for estimating thermodynamic properties of weakly-associated and non-associated oxygenated compounds, while the primarily attention has been paid to the elevated pressure data. The analysis indicates that the polar contribution of GC-PPC-SAFT has a negligibly small impact on predicting the high pressure data. Apparently, in the cases of the weakly- and non-associating compounds a major factor responsible for accuracy of the models at elevated pressures is the curvature of the dispersion contribution. At the same pressures CP-PC-SAFT tends to predict the lower values of densities and higher values of sound velocities. These predictions of CP-PC-SAFT are particularly accurate in the cases of slightly polar compounds with reliable values of the critical constants. Both models are capable of yielding only raw estimations of C-p. Although CP-PC-SAFT has a clear advantage in predicting the available compressibility data, GC-PPC-SAFT is superior in qualitative estimating the isobaric thermal expansion coefficients. However the major advantage of GC-PPC-SAFT is the more accurate estimation of the vapor pressures away from the critical points. (C) 2015 Elsevier B.V. All rights reserved.