Estimation of Structural Parameters of Protic Ionic Liquids for Activity Coefficient Models and Calculations of LLE Phase Diagrams

Modeling liquid–liquid equilibrium (LLE) is essential for optimizing the operation and safety of chemical engineering processes. Therefore, some researchers have investigated the modelling of ternary systems containing protic ionic liquids. In most cases, thermodynamic modeling was performed using the non-random two-liquid model (NRTL) for its simplicity and the absence of structural parameters. UNIQUAC model has also been used, but the structural parameters of protic ionic liquids are still scarce. In this work, the area and volume parameters were calculated by Connolly's method. The parameters obtained were used to correlate LLE data for thirteen ternary systems, among these we can high light (m-2HEAA, m-2HEABor, m-2HEAH) + DBT+ dodecane. Therefore, the estimated structural parameters allowed to generate seventy-eight interaction parameters between the solvent and the ionic liquid. New structural parameters protic ionic liquids were estimated. The results are shown with standard deviations between the calculated and experimental compositions with satisfactory results.