New mixing rules in simple equations of state for representing vapour-liquid equilibria of strongly non-ideal mixtures☆

Simple ionic liquids have long been held to be designer solvents, based upon the ability to independently vary their cations and anions. The formation of mixtures of ionic liquids increases this synthetic flexibility. We review the available literature of these ionic liquid mixtures to identify how their properties change and the possibility for their application.

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Mixtures of ionic liquids.

https://pubs.rsc.org/en/content/articlepdf/2014/GC/C3GC41389F

Mixing ionic liquids – “simple mixtures” or “double salts”?

Prompted by the observation that recent literature displays marked disagreement as to the proper treatment of data on the refractive indices of binary liquid mixtures, this paper clarifies the relationships among refractive index, molar volume and molar refraction and the corresponding mixing properties. It is shown that the molar refraction deviation function must be calculated on a mole fraction basis and the refractive index deviation function on a volume fraction basis, which makes it directly interpretable as a sign-reversed measure of the deviation of reduced free volume from ideality.

Refractive indices, molar volumes and molar refractions of binary liquid mixtures: concepts and correlations

Deep eutectic solvents (DES) are new emerging alternatives to conventional ionic liquids that may find a number of interesting applications in industrial and chemical processes. In this study, the densities, ρ, and refractive indices, nD, of the DESs (choline chloride + ethylene glycol) and (choline chloride + glycerol) and their aqueous mixtures were investigated at atmospheric pressure over the temperature range 298.15–333.15 K and across a complete composition range. The excess molar volumes, VE, and refractive index deviations, ΔnD, were also calculated from experimental results. The calculated excess molar volumes were negative at all temperatures over the entire range of composition considered, suggesting the presence of strong interactions between water and the DES in the mixtures. The refractive index deviations, on the other hand, were found positive in the entire concentration range. The calculated properties were fitted to a Redlich–Kister type equation to correlate them to the temperature and composition. The correlations used satisfactorily represent the densities and refractive indices of the pure DESs and their aqueous binary mixtures as functions of temperature and composition as indicated by the low overall average absolute deviations obtained in the calculations.

Densities and refractive indices of the deep eutectic solvents (choline chloride + ethylene glycol or glycerol) and their aqueous mixtures at the temperature ranging from 298.15 to 333.15 K

Refractive indices for the systems benzene-cyclohexane, acetone-cyclohexane have been measured at 25 o C over the composition range. These results, combined with the corresponding densities published earlier by us, were used to test the applicability of the Lorenz-Lorenz, Gladstone-Dale, Wiener, Heller, and Arago-Blot refractive index mixing rules. The Lorenz-Lorenz relation gave the best correlation for all systems investigated. The specific refractivities for mixtures studied were also calculated

Use of mixing rules in predicting refractive indexes and specific refractivities for some binary liquid mixtures

Excess volumes of acetone + benzene, acetone + cyclohexane, and acetone + benzene + cyclohexane at 298.15 K

Vapour—liquid equilibria of the systems acetone—benzene, benzene—cyclohexane and acetone—cyclohexane at 25°C

Refractive index and density for (acetone + benzene + cyclohexane) at 298.15 K are reported. Changes of refractivity and of volume on mixing over the composition range were derived. Relations for predicting these changes were established and analyzed

Dušan K. Grozdanić

Papers

Use of mixing rules in predicting refractive indexes and specific refractivities for some binary liquid mixtures

Excess volumes of acetone + benzene, acetone + cyclohexane, and acetone + benzene + cyclohexane at 298.15 K

Vapour—liquid equilibria of the systems acetone—benzene, benzene—cyclohexane and acetone—cyclohexane at 25°C

Refractive Indices and Densities of the System Acetone + Benzene + Cyclohexane at 298.15 K. Changes of Refractivity and of Volume on Mixing

Computer Design and Analysis of Operation of a Multiple-Effect Evaporator System in the Sugar Industry