Ionic Liquid Mixtures—An Analysis of Their Mutual Miscibility

Omar, Salama; Lemus, Jesús; Ruiz, Elia; Ferro, Víctor R.; Ortega, Juan; Palomar, José

doi:10.1021/jp411527b

Cited by 42 publications

(44 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As can be seen, polar compounds with HB donor character (as water, methanol and chloroform) present strong exothermic mixtures with 3c, determining the negative g E values, even when entropic contribution decreases the spontaneity of the mixture. COSMO‐RS provides the contributions of the different intermolecular interactions to the h E , (Figure B), which is a valuable information contributing to understand the mixing phenomena at molecular level ,,…”

Section: Resultsmentioning

confidence: 99%

Molecular and Thermodynamic Properties of Zwitterions versus Ionic Liquids: A Comprehensive Computational Analysis to Develop Advanced Separation Processes

2018

Self Cite

View full text Add to dashboard Cite

Zwitterion ionic liquids (ZIs) are compounds in which both counterions are covalently tethered, conferring them with unique characteristics; however, most of their properties are still unknown, representing a bottleneck to exploit their practical applications. Herein, the molecular and fluid properties of ZIs and their mixtures were explored by means of quantum chemical analysis based on the density functional theory (DFT) and COSMO‐RS method, and compared against homologous ionic liquids (ILs) to provide a comprehensive overview of the effect of the distinct structures on their physicochemical and thermodynamic behavior. Overall, ZIs were revealed as compounds with higher polarity and stronger hydrogen‐bonding capacity, implying higher density, viscosity, melting point, and even lower volatility than structurally similar ILs. The phase equilibrium of binary and ternary systems supports stronger attractive interactions between ZIs and polar compounds, whereas higher liquid–liquid immiscibility with nonpolar compounds may be expected. Ultimately, the performance of ZIs in the wider context of separation processes is illustrated, while providing molecular insights to allow their selection and design for relevant applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Molecular and Thermodynamic Properties of Zwitterions versus Ionic Liquids: A Comprehensive Computational Analysis to Develop Advanced Separation Processes

2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…An elaborate introduction of the COSMO‐RS model and its applications in calculating different thermodynamic properties can be found in literature . It has been widely demonstrated to be able to provide good qualitative and in many cases acceptable quantitative predictions on the thermodynamic properties of IL‐involved systems, and is thus also promising for estimating the separation performances of DSILs …”

Section: Evaluation Of Key Degrees Of Freedom For Dsils Designmentioning

confidence: 99%

Rational design of double salt ionic liquids as extraction solvents: Separation of thiophene/n‐octane as example

Song

Zhou

et al. 2019

AIChE Journal

View full text Add to dashboard Cite

Although double salt ionic liquids (DSILs) offer significant advantages over classical twoion ionic liquids as separation solvents, relevant studies are still scarce and a systematic DSIL selection method is thus highly desirable. In this contribution, a rational method for designing DSILs as extraction solvents is proposed and exemplified by the thiophene/ n-octane separation. The effects of additional degrees of freedom for DSIL design (i.e., double cations and/or anions and the ion ratio) on the thermodynamic properties are first analyzed by COSMO-RS. Then, a multilevel DSIL design method combining the prediction of infinite dilution thermodynamic properties, the estimation of physical properties, the evaluation of phase equilibrium behavior, and the experimental validation is proposed. By applying this method, [C 2 MIm][OAc] x [NO 3 ] 1-x (x = [0, 1]) and [C 2 MIm] [OAc] x [SCN] 1-x (x = [0.70, 1]) are identified as promising DSIL solvents for the thiophene/ n-octane separation. Correspondingly, the liquid-liquid equilibria of {DSILs + thiophene + n-octane} with the designed DSILs are experimentally studied. K E Y W O R D S COSMO-RS, double salt ionic liquids, liquid-liquid equilibrium, solvent design, thiophene/ n-octane separation 1 | INTRODUCTION During the past decades, ionic liquids (ILs) have sparked significant interest for application in various separation processes due to their overwhelming advantages over conventional organic solvents, such as negligible vapor pressure, broad liquid range, designable and tunable character, and so on. 1-10 However, as known to all, various cationanion combinations can lead to very different physical and thermodynamic properties, making the selection of ILs the most crucial task for the development of IL-based separation processes. 4-10 A large number of experimental and theoretical studies have been reported on the identification of suitable ILs for different separation processes. 7-25 Particularly, several research groups have employed COSMO-based activity coefficient models 12-19 or the UNIFAC-IL model 20-25 to perform computational screening and design of ILs as separation solvents. Because of the predictive character of these thermodynamic models, the separation performance of ILs that have not been experimentally covered can be estimated and thus the identification of suitable solvent candidates in a large range is possible. Despite the progress made, the selection of practically attractive IL for a specific process is still challenging as in many cases very few ILs can satisfy different desirable properties simultaneously. For instance, when screening ILs as extractive desulfurization solvent, Song et al found that only 831 of the initial 36,260 cation-anion combinations meet the thermodynamic property requirements, among which only 15 satisfy the physical property constraints. 16 Conceivably, if more restrictions such as easy preparation, commercial availability, low cost, and so on of ILs are considered, the number of feasible solvents will be further reduced...

show abstract

“…156 Studies on mutual miscibility of tetrafluoroborate PILs with common solvents, such as cyclic hydrocarbons 157 and diols 158 were also reported. Mixtures of immiscible ionic liquids including PILs were investigated by Palomar and co-workers, 159 demonstrating the potential of biphasic IL mixtures for extraction/ separation procedures. The Coutinho group observed that mixtures of ionic liquids enabled the formation of eutectic systems with very low melting points.…”

Section: Preparation and Characterisationmentioning

confidence: 99%