Estimation of Thermodynamic Properties and Phase Equilibria in Systems of Deep Eutectic Solvents by PC-SAFT EoS

Abstract

This study examines the capabilities and shortcomings of perturbed-chain-statistical associating fluid theory equations of state (PC-SAFT EoS) applied for predicting properties and phase equilibria in systems of deep eutectic solvents. Treating deep eutectic solvents as pseudo-pure compounds and describing them as mixtures of two independent constituents are explored. Examples of choline chloride as the hydrogen bond acceptor (HBA) and levulinic acid, ethylene glycol, and phenol as hydrogen bond donors (HBDs) in a 1:2 molar ratio are considered. Excess properties of deep eutectic solvents with n-alkanols and water along with solubilities of carbon dioxide and ammonia are also considered. Besides that, liquid–liquid ternary systems of deep eutectic solvents with n-alkanes and 1-alkanols are analyzed. It has been found that although the pseudo-pure compounds approach with 2B associative scheme correctly estimates excess volumes, it exhibits poor accuracy in predicting excess enthalpies, solubility data, and liquid–liquid equilibria in ternary systems. When a temperature-dependent binary interaction between HBA and HBDs is applied, the individual approach predicts these properties in a more accurate manner.