To understand the molecular interactions among the components of aqueous solutions with cholinium based aprotic ionic liquids (AILs), their partial molar properties have been studied. Four cholinium based AILs-namely, cholinium propanoate ([Chl][Pro]), cholinium butanoate ([Chl][But]), cholinium pentanoate ([Chl][Pen]) and cholinium hexanoate ([Chl][Hex]) were synthesized and characterized. Thermodynamic properties of these AILs in water at various temperature (293.15 to 333.15) K and at atmospheric pressure were determined from density and speed of sound measurements. Derived thermodynamic properties and related empirical parameters at infinite dilution were also determined using the Redlich-Mayer type of equation. The studied AILs are observed to interact strongly with water, although the ion-solvent interactions decrease with increase in temperature as well as with increase in concentration. © 2018 Elsevier B.V.

Ramesh L. Gardas

Department Of Chemistry

Somenath Panda

Architectural acoustics

Atmospheric pressure

Ionic liquids

Liquids

Molecular interactions

Molecular Structure

Solutions

Temperature

Thermodynamic properties

CHOLINE-BASED IONIC LIQUIDS

EMPIRICAL PARAMETERS

HEXANOATE

INFINITE DILUTION

ION-SOLVENT INTERACTIONS

PARTIAL MOLAR PROPERTIES

PROPANOATE

REDLICH-MAYER EQUATION

Atmospheric temperature

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Molecular Liquids

In this study, the solvation behaviour of monosaccharide's in aqueous solutions of newly synthesized ionic liquid: cholinium propanoate [Chl][Pro] has been studied at various temperatures and concentrations. The volumetric properties of two monosaccharides (viz. D (+)glucose and D (+)-xylose) were evaluated from density and speed of sound data. Apparent molar volume, V2,φ and apparent molar isentropic compressibility, Ks,2,φ calculated from experimental data were used to evaluate respective infinite dilution values (X2 º = V2 º or Kº s,2). The volumetric transfer volumes (ΔtV2 º or ΔtKº s,2) were also evaluated to analyze the solute-co-solute interactions. The ΔtV2 º and ΔtKº s,2 values reveal that the interaction between ionic liquid and monosaccharides increases with concentration and temperature. The positive transfer parameter reveals hydrophilic-ionic interactions as evaluated from structural interaction model. © 2019 Elsevier B.V.

Volumetric and compressibility studies of monosaccharides in aqueous cholinium propanoate [Chl][Pro] solutions at different temperatures

The precise and accurate thermophysical properties determination of ionic liquid (IL)-solvent binary system is needed for understanding the molecular interactions occurring between these components. The nature of ion-ion and ion-solvent interactions can be studied either experimentally on the basis of apparent and partial molar properties and corresponding infinite dilution properties or by computational studies. In this regard, we have measured the thermodynamic properties of binary aqueous solutions containing newly synthesized N-methylpyrrolidone based protic ionic liquids (PILs) in the temperature range (288.15–328.15) K and at ambient pressure. Experimentally measured density and speed of sound data have been used to calculate the infinite dilution partial molar properties and the corresponding empirical parameters through the Redlich-Mayer type of equation. It is observed that the studied PILs interacts strongly with water, however the ion-solvent interactions decreases with increase in anionic chain length and increase in temperature. Observed intra-ionic and inter-ionic interactions in studied aqueous ionic liquid mixtures were also supported by Density Functional Theory (DFT) calculations. © 2017 Elsevier B.V.

Fluid Phase Equilibria

Understanding ion-ion and ion-solvent interactions in aqueous solutions of NMP based protic ionic liquids through partial molar properties and DFT calculations

The nature of interactions between biopolymers (polysaccharides) and ionic liquids (ILs) governs the dissolution/functionalization processes, so an understanding of these interactions demands reliable reference data on thermophysical properties of systems composed of biopolymer model compound (monosaccharide), ILs and solvent (water). In this regard, we report herein the volumetric properties of D(+)-glucose (Glu) in aqueous solutions of protic ionic liquid (propylammonium formate; PAF) at different concentrations and temperatures. The experimental results were further supported by computational studies. Structures of Glu and PAF were optimized in gas phase by employing density functional theory at CAM-B3LYP/6-311G++ (2d, 2p) level. Further, interactions between the two in presence of solvent (water) were studied by employing implicit as well as explicit solvent models. The hydrophilic-ionic interactions between Glu and PAF are significant at lower concentrations of PAF and diminish with increasing concentration of PAF as well as temperature. Overall, hydrophobic type of interactions between Glu and ions of PAF dominate the solvation behaviour at higher concentration and temperature, and these observations have been further supported by computational results. © 2016 Elsevier Ltd

Journal of Chemical Thermodynamics

Implicit and explicit solvent models to understand the D(+)-glucose solvation in aqueous protic ionic liquid solution: Volumetric and computational approach

In this work, two pyrrolidonium based ionic liquids namely N-methyl pyrrolidonium bisulfate ([NMP][HSO4]) and pyrrolidonium bisulfate ([PY][HSO4]) were synthesized and characterized by 1H NMR spectroscopy technique. The experimental density, speed of sound, viscosity and conductivity have been measured in the temperature range of (293.15–333.15) K and at 0.1 MPa pressure. From the experimental data, derived thermodynamic properties such as molecular volume, standard entropy, crystal energy, isobaric expansion coefficient, molecular free length and molar conductivity have been calculated. Empirical equations, Newton–Laplace equation, Vogel–Tammann–Fulcher equation and Walden equation were presented to understand the nature of the pure ionic liquids. Further, experimental measurements for density and speed of sound of binary mixtures of [PY][HSO4] with water and/or DMSO were studied as a function of IL concentration at various temperatures and apparent molar properties were calculated using Redlich-Mayer equation. Finally, experimental and derived thermodynamic properties were explored to understand the intermolecular interactions of studied systems. © 2016 Elsevier B.V.

Synthesis and thermophysical properties of pyrrolidonium based ionic liquids and their binary mixtures with water and DMSO at T = (293.15 to 333.15) K

Apparent molar volumes and apparent molar isentropic compressibilities of newly synthesized ammonium-based protic ionic liquid (PIL), namely diethylethanolammonium propionate, at T = (293.15 to 328.15) K and at atmospheric pressure were obtained from experimentally measured density and speed of sound data. Redlich-Mayer type of equation was used to calculate infinite dilution apparent molar volumes, V2 ∞, infinite dilution apparent molar isentropic compressibilities, Ks,2 ∞, and corresponding empirical parameters (Sv, Bv, Sk, and Bk). Positive magnitude of limiting volumetric slope Sv versus m1/2 for protic ionic liquid (PIL) + water binary solutions, suggests that PIL-water interactions are weak. Further, the temperature dependence of V2 ∞ values has also been evaluated. © 2015, Springer-Verlag Berlin Heidelberg.

Ionics

Apparent molar properties of aqueous protic ionic liquid solutions at T = (293.15 to 328.15) K

Precise determination of thermodynamic properties of binary mixtures containing ionic liquids (ILs), plays an important role in process design and potential engineering applications of these mixtures. Thermodynamic studies can provide an insight into the nature of intermolecular interactions occurring between the solute and solvent in solutions. In this regard, thermodynamic properties of 1,8-diazabicyclo[5.4.0]undec-7-en-8-ium trifluoroacetate [DBUTFA] in two organic solvents viz. N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) have been evaluated at different temperatures (293.15 to 328.15) K. Apparent molar property data were fitted to a Redlich-Mayer type of equation to compute infinite dilution values and empirical parameters. The experimental studies suggest that the nature of the interactions between DBUTFA and organic solvents are influenced by temperature. DBUTFA interacts more strongly with DMF at low temperature (<308.15 K), whereas it interacts more strongly with DMSO at higher temperatures (>308.15 K). Density functional level of theory (DFT) was employed to investigate intra-ionic and inter-ionic interactions between the ions of PIL and organic solvents. The computational results are in good agreement with experimental results. 2016 The Royal Society of Chemistry.

RSC Advances

Elucidation of molecular interactions between a DBU based protic ionic liquid and organic solvents: Thermophysical and computational studies

Molecular interactions of choline based ionic liquids with water at different temperatures: An experimental study

Journal	Data powered by TypesetJournal of Molecular Liquids
Publisher	Data powered by TypesetElsevier B.V.
ISSN	01677322
Open Access	No