ePC-SAFT advanced – Part II: Application to Salt Solubility in Ionic and Organic Solvents and the Impact of Ion Pairing

Prediction of salting‐out in liquid‐liquid two‐phase systems with ePC‐SAFT: Effect of the Born term and of a concentration‐dependent dielectric constant

“…(4) is ePC‐SAFT. The most recent version is called ‘ePC‐SAFT advanced’, and it contains the Born term altered by a concentration‐dependent dielectric constant [43] . The theory is briefly discussed in the following.…”

“…Later, PC‐SAFT was extended to include electrostatic interionic interactions [59] and to account for the change of the dielectric constant at different concentrations [34] . Recently, an altered Born term was introduced within ePC‐SAFT, [43] which accounts for electrostatic interactions between charged components and their surrounding medium. The resulting residual Helmholtz energy is given as the sum of all contributions according to Eq.…”

“…Unfortunately, while the development of processes mainly based on aqueous electrolyte systems can be considered as well‐optimized, water‐poor electrolyte systems still require a lot of data and of understanding thermo‐physical behavior at different conditions (solvent composition, kind and concentration of dissolved electrolytes). Modeling the phase behavior of electrolyte systems has been performed by different groups; these already included the Born theory into thermodynamic models e. g., the electrolyte Cubic‐Plus‐Association (eCPA), [22–24] Peng‐Robinson [25,26] and Soave‐Redlich‐Kwong [22] models and electrolyte Perturbed‐Chain Statistical Associating Fluid Theory (ePC‐SAFT) [27–42] as well as the most recent version, ‘ePC‐SAFT advanced’ [43] . In that work the Born term was altered by a concentration‐dependent dielectric constant.…”

“…In that work the Born term was altered by a concentration‐dependent dielectric constant. This allowed for a more predictive treatment of binary data (activity and osmotic coefficients) and for calculation of transfer properties (Gibbs free energies of solvation and transfer) [43] .…”

“…In the present work, ‘ePC‐SAFT advanced’ which includes an altered Born term [43] was further investigated for predicting LLE of mixed solvents containing dissolved electrolytes. Furthermore, the role of an appropriate expression of the dielectric constant as function of the system composition was studied with respect to the impact on the quality of the predicted LLE.…”