Development and Extension of the NRTL Functional Activity Coefficient (NRTL-FAC) Model Using High Quality and Critically Evaluated Phase Equilibria Data. 2

The non-randomness two-liquid model (NRTL) has been used widely in chemical engineering to calculate phase equilibria. Different forms of the NRTL model have been developed so far, including original NRTL, electrolyte NRTL (e-NRTL), polymer NRTL and segment-based NRTL (NRTL-SAC). All of the mentioned NRTL based models require experimental data to tune the interaction parameters. In the previous work (Fluid Phase Equilibria, 541 (2021) 113088), we have developed the NRTL functional activity coefficient (NRTL-FAC) model based on the high-quality experimental vapor-liquid equilibrium (VLE) data. In the present study, the number of NRTL-FAC groups was extended from 50 to 55. In addition, the temperature type of interaction parameters in the current version of the NRTL-FAC was changed compared to the previous version to better fit the experimental data. The quality of experimental data was checked using different thermodynamic consistency tests, including Herington test, Van Ness test, point test, infinite dilution test, EoS test, and endpoint test. Besides, 156 molecules with 55 main groups were used in the extension of the NRTL-FAC model. To account the combinatorial contribution of the NRTL-FAC model, the Stavermann-Guggenheim term was usd. Excellent agreement was obtained between the experimental data and model results. The NRTL-FAC activity coefficient model performs superior to other versions of group contribution models, including UNIFAC, UNIFAC-LBY, and UNIFAC-DMD models.