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

• The polar contribution has a negligibly small impact on predicting the high pressure data.
• CP-PC-SAFT predicts the lower values of densities and higher values of sound velocities.
• In the cases of the slightly polar compounds these predictions are more accurate.
• Such compounds can be included in the CP-PC-SAFT's applicability range.
• GC-PPC-SAFT has an advantage in predicting the vapor pressures away from critical points.

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 CP. 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.

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