Determining the dissociation extent of ionic liquids in water using the PDH + UNIQUAC model

Impact of extended long-range electrostatics on the correlation of liquid-liquid equilibria in aqueous ionic liquid systems

“…Consequently, in the past the purely electrostatic terms were complemented by virial expansions [52,53], where interactions between ions and solvents are described by empirical parameters for the excess Gibbs free energy. The conventional Pitzer-Debye-Hückel (PDH) equation has been successfully applied to aqueous systems composed of common salts and more complex compounds such as ILs [7,[17][18][19]31,32,34,44].…”

“…The combination between short and long-ranged interactions models is usually referred to as PDH + UNIQUAC model or eUNIQUAC, which consists of a summation of the excess Gibbs free energies 𝐺 E [44,55] as shown in Eq. (9):…”

“…As experiments may be time-consuming and costly, one proper tool to evaluate properties of different compounds in mixtures is predictive thermodynamic modeling. When considering IL-based systems, their behavior has been accurately modeled using equations of state (EoS) [12][13][14][15][16][17][18][19][20], such as the Perturbed Chain based on Statistical Associating Fluid Theory (PC-SAFT) and Cubic Plus Association (CPA), or excess Gibbs free energy (G E ) models [21][22][23][24][25][26][27][28][29][30][31][32][33][34], such as the Non-Random Two-Liquid (NRTL) [31,[35][36][37][38], UNIversal QUAsi-Chemical (UNIQUAC) and UNIversal Function group Activity Coefficient (UNIFAC) [24,26,[39][40][41][42][43][44] or even the predictive Conductor-like Screening Model for Realistic Solvents (COSMO-RS) [29][30][31][32][33][45][46][47]…”

“…Recently, interest in modeling more complex, concentrated, non-aqueous electrolytes has been growing and many approaches stick to Debye-Hückel theory, showing its applicability [7,[17][18][19]27,31,32,34,44]. However, application in these systems, particularly when highly concentrated, requires consideration of the changing mixture properties, such as density, molar mass and, most importantly [55], the relative permittivity.…”

Study on vapor–liquid equilibrium and microscopic properties of DL-proline, L-glutamic acid, and L-serine aqueous solutions

“…Proton activity is used to predict pH in multiphase systems, and the developed framework considers reaction and phase equilibria ( Gabriele et al, 2022 ). Macedo et al used the PDH (Pitzer–Debye–Hückel equation) + unique model to determine the degree of dissociation of ionic liquids in water ( Eugenia et al, 2022 ). However, to the best of our knowledge, studies on amino acid phase equilibria and their microscopic mechanism of action have been sparse until now.…”