Vapor PressureOsmometry and Thermodynamic Modelingof Aqueous Protic Ionic Liquids Based on 2‑HydroxyethylammoniumLactate

The osmotic coefficient is the most important quantity for the electrolyte system that can be used to describe the behavior and study the interactions that occur in the systems. The osmotic coefficients for the protic ionic liquids, the aqueous 2-hydroxyethylammonium lactate, bis[2-hydroxyethylammonium] lactate, and tris[2-hydroxyethylammonium] lactate ionic liquids have been measured at a temperature range of (298.15–328.15) K with vapor pressure osmometry. The water activity and vapor pressure depression of water have been determined. The extended Pitzer–Archer model was used to correlate the experimental osmotic coefficients. The average standard deviation for the osmotic coefficient values in the binary system with the Pitzer–Archer model was 0.002. Also, the e-NRTL model was used to correlate the activity coefficients of water. Finally, Hansen solubility parameters were used to study the solute–solvent interactions.