Using binary mixtures of dicationic ionic liquids for determination of activity coefficients at infinite dilution by gas–liquid chromatography

Heydar, Kourosh Tabar; Gharavi, Halime; Nazifi, Mina; Mirzaei, Mojtaba; Sharifi, Ali

doi:10.1016/j.fluid.2013.05.038

Cited by 9 publications

(2 citation statements)

References 30 publications

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“…Techniques such as gas–liquid chromatography, , high-performance liquid chromatography, and differential ebulliometry ,, are traditionally used to measure activities in extremely dilute systems at varying concentrations, leading to the IDAC by extrapolation . There has been considerable interest in predicting these coefficients − ,,− due to their use in phase equilibria studies in chemical engineering applications. ,,, …”

Section: Methodsmentioning

confidence: 99%

Infinite Dilution Activity Coefficients as Constraints for Force Field Parametrization and Method Development

Matos

Calabró²,

Mobley

2019

J. Chem. Theory Comput.

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Molecular simulations begin with an underlying energy model or force field, and from this, can predict diverse physical properties. However, force fields were often developed with relatively limited datasets, yet accuracy for diverse properties across a broad chemical space is desirable, so tests of such accuracy are particularly important. Here, to this end, we calculate 237 infinite dilution activity coefficients (IDACs), comparing with experimental values from NIST’s ThermoML database. We found that calculated IDAC values correlate strongly with experiment (Pearson R of 0.92±0.01), and allow us to identify specific functional groups which appear to present challenges to the force field employed. One potentially valuable aspect of IDACs, as compared to solvation free energies which have been frequently employed as force field tests, is that the same molecules serve both as solutes and solvents in different cases, allowing us to ensure force fields are not overly tuned to one particular environment or solvent.

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Section: Methodsmentioning

confidence: 99%

Infinite Dilution Activity Coefficients as Constraints for Force Field Parametrization and Method Development

Matos

Calabró²,

Mobley

2019

J. Chem. Theory Comput.

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“…5 Techniques such as gas-liquid chromatography, 5,10 high-performance liquid chromatography 10 and differential ebulliometry 5,10,11 are traditionally used to measure activities in extremely dilute systems at varying concentrations, leading to the infinite dilution activity coefficient by extrapolation. 10 There has been considerable interest in predicting these coefficients [5][6][7][10][11][12][13][14][15][16][17][18][19][20][21] due to their use in phase equilibria studies in chemical engineering applications. [2][3][4]14 IDACs (also represented by γ ∞ ) are related to solvation free energies by the following equation: 6,7,13…”

Section: Introductionmentioning

confidence: 99%

Infinite Dilution Activity Coefficients as Constraints for Force Field Parameterization and Method Development

Matos¹,

Calabró²,

Mobley³

2018

Preprint

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<p>Molecular simulations see widespread use in calculating various physical properties of interest, with a key goal being predictive molecular design. These simulations, including molecular dynamics (MD) simulations, begin with a underlying energy model or force field and then, based on this model, use simulations to compute properties of interest. However, one of the most significant challenges in molecular dynamics and modeling studies is ensuring that the force field is a good enough approximation of the underlying physics that computed quantities can be used to reproduce experimental properties with the desired level of accuracy. Parameterization of force fields depend on various experimental properties including as much of the chemistry of interest as possible. Physicochemical properties measurable in a relatively straightforward manner are particularly interesting for developers. Such properties can be measured for a relatively diverse chemical set and used to expand the parameterization dataset as needed. Here, we examine infinite dilution activity coefficients (IDACs) which are experimental quantities that can play this role. We retrieved 237 empirical IDACs from NIST's ThermoML, a database of measured thermodynamic properties, and we estimated the corresponding values using solvation free energy calculations. We found that calculated IDAC values correlate strongly with experiment. Specifically, the natural logarithm of calculated and experimental IDAC values shows a Pearson correlation coefficient of 0.85+/-0.02. The calculated IDAC values allow us to identify strengths and potential weaknesses of force field parameters for specific functional groups in solutes and solvents, suggesting these may be a valuable source of data for force field parameterization, capturing some of the same type of information as hydration and solvation free energies and thus potentially providing a useful new source of experimental data.</p>

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A chemometric approach to characterization of ionic liquids for gas chromatography

et al. 2014

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A chemometric study was carried out to characterize three ionic liquid types (ILs) with hexacationic imidazolium, polymeric imidazolium, and phosphonium cationic cores, using a range of contra-anions such as halogens, thiocyanate, boron anions, triflate, and bistriflimide. The solvation parameter model developed by Abraham et al., unsupervised techniques as cluster analysis (CA), and supervised techniques as linear discriminant analysis (LDA), step-LDA, quadratic discriminant analysis (QDA), and multivariate regression techniques as discriminant partial least squares (D-PLS), or multiple linear regression (MLR) were used to characterize the functionalized ILs above. CA established two main groups of phases, those with an acidic H-bond and those with basic ones. Once detected, the two natural groups, a linear and quadratic delimiters with good classification (>96 %) and prediction (>92 %) capacities were computed. The use of step-LDA technique allowed us to establish that a, b, and s solvation parameters were the most discriminant variables. These variables were used for modeling purposes, and a D-PLS and MLR models were constructed using a binary response. The explained variance of categorical variable by the model validated by cross-validation was 65 %, and 94.5 % of ILs were correctly predicted. IL characterization carried out would allow the appropriate selection of phases for gas chromatography (GC).

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Using binary mixtures of dicationic ionic liquids for determination of activity coefficients at infinite dilution by gas–liquid chromatography

Cited by 9 publications

References 30 publications

Infinite Dilution Activity Coefficients as Constraints for Force Field Parametrization and Method Development

Infinite Dilution Activity Coefficients as Constraints for Force Field Parametrization and Method Development

Infinite Dilution Activity Coefficients as Constraints for Force Field Parameterization and Method Development

A chemometric approach to characterization of ionic liquids for gas chromatography

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