This study demonstrates that in addition to association, polarity, and other interactions, phase equilibria of the ionic liquid (IL) systems are also influenced by the global phase diagram factors, namely, the differences between values of the pure compound critical points. As these differences increase, increasing thus the system asymmetry, the extent of phase splits also increases, and the molar solubilities correspondingly decrease. It is shown that the pressure dependence of the IL densities indicate the higher experimentally inaccessible T c and P c values, making their systems more asymmetric, which reduces the solvent capacities and vice versa. In addition to this, phase equilibria are also influenced by the critical constants of the solvents. Their higher T c and P c values typically increase the symmetry, and therefore, the solubilities. The CP-PC-SAFT equation of state rigorously obeys the T c and P c of solvents and accurately represents the densities of ILs under a wide range of conditions. Such features endow this model with a remarkable predictive potential even while neglecting the association and polar interactions. In most of the cases, CP-PC-SAFT with k 12 = 0 correctly estimates the differences between solubilities in the experimentally investigated systems comprising fluoro- and chloromethanes, ethanes, ethenes, propanes, and propenes with [C2mim]­[Ntf2], [C4mim]­[Ntf2], [C6mim]­[Ntf2], [C8mim]­[Ntf2], [C4mim]­[PF6], [C4mim]­[BF4], and [C8mim]­[BF4]. The quantitative accuracy of this model is usually reasonably good as well. Although SAFT-VR-Mie obeys the literature T c values of solutes, it overestimates their P c. In addition to this, it yields higher imaginary critical constants of the considered ILs than CP-PC-SAFT. These factors may explain its tendency to underestimate the solubility data with k 12 = 0. Nevertheless, in most of the cases, SAFT-VR-Mie correctly describes the solubility tendencies in the considered systems.

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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.

This study compares the estimations of two predictive approaches, namely, CP-PC-SAFT and CS-SAFT-VR-Mie for vapor pressures, saturated and high-pressure densities, sound velocities, isobaric and isochoric heat capacities of 17 representative substituted fluoro- and chloromethanes, ethanes, ethenes, propanes, and propenes, whose data are available under a wide range of conditions. Predictions of vapor–liquid equilibria (VLE) in their binary systems comprising inter alia carbon dioxide, hydrocarbons, and light gas systems with k 12 = 0 are considered as well. These models do not incorporate associative and polar interactions, which allows parametrization based on the particularly limited amount of literature data. It is demonstrated that although the overall accuracies of the considered approaches are reasonably good, each of them has their advantages and disadvantages. For example, SAFT-VR-Mie typically predicts more accurately some VLE in the symmetric systems, while CP-PC-SAFT is advantageous in estimating phase behavior of the asymmetric ones. Both models can be applied for preliminary estimation of unavailable halocarbon data for which each of them exhibits a relative superiority. In addition to this, it is demonstrated that SAFT-VR-Mie attached by square gradient theory with predictive correlation for influence parameters accurately estimates surface tensions of the considered compounds.

In this work, the activity of horseradish peroxidase (HRP) in betaine-based natural deep eutectic systems (NADES) was measured and studied by molecular simulations. Focus was laid on enzymatic activity in...