Excess Molar Enthalpies Research Articles

Isothermal Titration Calorimetric Study of Ionic Liquid Solutions in Alcohols at Extreme Dilutions: An Investigation of Ion–Solvent Interactions

In this work an effort has been made to show the effect of an alcohol-rich environment on imidazolium-based ionic liquids at 298.15 K using an isothermal titration calorimeter. It is divulged from this study that the thermal behavior expressed in terms of excess partial molar enthalpy, \( H_{\text{IL}}^{\text{E}} \), of ionic liquids in various linear alcohols is governed by the increasing hydrophobicity of the residual alkyl group attached to the cation of an ionic liquid and to the alcohol molecules. An interesting observation about the systems consisting of ethylated residuals on both the cations of the ionic liquid and the alcohol molecules is that these systems do not follow the trend exhibited by other ionic liquid–alcohol systems. Interesting information on ionic interactions is obtained by using a simple methodology that gives the enthalpic interaction parameter \( H_{{I{\text{L - IL}}}}^{\text{E}} \).

Thermal performance of an absorption-refrigeration system with [emim]Cu2Cl5/NH3 as working fluid

The vapor pressures of [emim]Cu2Cl5/NH3 at ammonia mole fractions (x1) ranging from 0.90 to 0.96 at temperatures (T) ranging from 303.15 K to 483.15 K were determined by employing a static method. The correlation of experimental data was calculated by using a modified UNIFAC (Dortmund) model with a total uncertainty of <4.1%. The specific enthalpy of [emim]Cu2Cl5/NH3 binary solution was also calculated on the basis of the predictive excess molar enthalpy of the UNIFAC model. The thermal performance of an absorption refrigeration system with [emim]Cu2Cl5/NH3 as working fluid was simulated. The thermal performance of the [emim]Cu2Cl5/NH3 system is better than those of absorption systems with NH3/H2O, [choline][NTf2]/NH3, [emim][Ac]/NH3, and [emim][EtOSO3]/NH3 as working fluids. The coefficients of performance and exergy efficiency of the [emim]Cu2Cl5/NH3 system are slightly lower than those of the LiBr/H2O system. The evaporating temperature scope of the former is wider than that of the latter. The [emim]Cu2Cl5/NH3 system also possesses several advantages, including non-crystallization and non-corrosion.

Experimental study on the calorimetric data of 2-butoxyethanol with aliphatic alcohols (C1–C4) and correlation with the Wilson, NRTL and UNIQUAC models at T = 298 K

Excess molar enthalpies, HmE of binary mixtures of 2-butoxyethanol with methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol and butan-2-ol were calculated from calorimetric data at T=298K and ambient pressure (81.5kPa). Calorimetric measurements were performed with employing a Parr 1455 solution calorimeter in an isolated room. All the binary mixtures showed endothermic behavior except 2-butoxyethanol+methanol mixture which showed exothermic behavior over the entire range of compositions. The experimental data were then used to calculate excess partial molar enthalpies, HiE and excess partial molar enthalpies at infinite dilution, HiE,∞. The maximum HmE values were observed about 0.45–0.5mol fraction of 2-butoxyethanol. HmE increases as the length and the branch chains of the alcohols increase. Finally, the experimental results were correlated by using the Redlich–Kister equation and three thermodynamic models (Wilson, NRTL, and UNIQUAC) based on the local composition theory.

Solubility of 2-Ethylanthraquinone in Binary Mixtures of Oligooxymethylene Dimethyl Ethers with Different Number of CH2O Groups of n = 2, 3, and 4 from 293.15 to 343.15 K

The solubility of 2-ethylanthraquinone in binary mixtures of oligooxymethylene dimethyl ethers with different number of CH2O groups of n = 2, 3, and 4 (PODE3 + PODE4, PODE2 + PODE4, and PODE2 + PODE3) were measured by a synthetic method with a laser monitoring observation technique at the temperature range from 293.15 to 343.15 K at 101.325 kPa. The solubility data were correlated by the modified Apelblat model, λh equation, Wilson model, and the nonrandom two liquid (NRTL) model. The correlation results demonstrated that the NRTL model was the proper model with higher accuracy. Therefore, NRTL model was used to represent the temperature dependence of the molar fraction solubility. Furthermore, the partial molar excess Gibbs free energy, the partial molar excess enthalpy, and the partial molar excess entropy for 2-ethylanthraquinone dissolution were calculated using the activity coefficients (NRTL model).

Thermodynamics and activity coefficients at infinite dilution for organic solutes in the ionic liquid 1-hexyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide

Activity coefficients at infinite dilution (γi∞) and gas-liquid partition coefficients (KL) for organic solutes: n-alkanes, alkenes, alkyl benzenes, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, and chloromethanes in the ionic liquid (IL) 1-hexyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ([HMMIM][NTf2]) have been measured by the gas-liquid chromatographic method (GLC) in the temperature range of (313.15–353.15)K. The thermodynamic functions at infinite dilution as partial molar excess enthalpies at infinite dilution (H‾iE,∞) were derived from the temperature dependence of the γi∞ values. Gibbs energies (G‾iE,∞) and entropies (TrefS‾iE,∞) of organic solutes in [HMMIM][NTf2] at a reference temperature Tref=298.15K were also calculated from the γi∞ values. The solubility parameters of the IL [HMMIM][NTf2] were determined by two methods. Selectivity (Sij∞) and capacity (kj∞) at infinite dilution at 323.15K have been determined for n-hexane (i)/benzene (j), cyclohexane (i)/benzene (j). The results were analyzed in comparison to literature data for alkylimidazolium-based ILs with [NTf2]−. For three isomeric xylenes separation problems, selectivity at 323.15K were also obtained from the γi∞ values.

Application of the UNIFAC models for prediction and description of excess molar enthalpies for binary mixtures of n-propanol, acetic acid, n-propyl acetate, and water

In this paper the ability of the UNIFAC methods (original UNIFAC and modified UNIFAC (Dortmund)) to predict the excess molar enthalpies, HE, is considered. The predicted and the obtained earlier experimental values of the excess molar enthalpies for 5 binary systems of n-propanol, acetic acid, n-propyl acetate, and water were compared. Since the both methods represent the HE unsatisfactorily, new set of group interaction parameters of the UNIFAC (Dortmund) method for mentioned above compounds was evaluated.

Separation of aliphatic from aromatic hydrocarbons and sulphur compounds from fuel based on measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid N,N-diethyl-N-methyl-N-(2-methoxy-ethyl)ammonium bis(trifluoromethylsulfonyl)imide

The activity coefficients at infinite dilution, γ13∞, for 53 different solutes including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, ethers, ketones, thiophene, acetonitrile, pyridine, 1-nitropropane and water in the ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide, [COC2N1,2,2][NTf2] were determined using inverse gas-liquid chromatography. The experiment has been performed at five temperatures over the range of (318.15 to 358.15)K. From experimental results, the partial molar excess Gibbs energy, ΔG1E,∞, enthalpy ΔH1E,∞ and entropy term TrefΔS1E,∞ at infinite dilution were calculated. Additionally, the gas-liquid partition coefficients of the solutes, KL were calculated. The value of selectivity, S12∞ and capacity, k2∞ at infinite dilution for hexane/benzene, cyclohexane/benzene, heptane/thiophene and heptane/pyridine separation processes were calculated directly from γ13∞. These parameters are compared to literature values of S12∞ and k2∞ for other ionic liquids and NMP, or sulfolane – solvents commercially used on an industrial scale in separation processes. Moreover, physicochemical properties of pure ILs that is: density, viscosity and surface tension have been determined as a function of temperature and basic thermal properties of pure [COC2N1,2,2][NTf2] were measured using DSC technique.

Experimental and Computational Studies of Binary Mixtures of Isobutanol + Cyclohexylamine

The densities and viscosities of binary mixtures of isobutanol + cyclohexylamine have been measured over the entire range of composition at the various temperatures (293.15–313.15 K) and at atmospheric pressure. From these measurements, the thermal expansion coefficients, isothermal coefficient of pressure excess molar enthalpy, excess molar volumes, and deviations in viscosities have been calculated too. The nonideality behavior of the mixture was evidenced in the excess molar volumes and deviations in viscosities. The results have been fitted to the Redlich–Kister polynomial equation. The Grunberg–Nissan equation was used to correlate the viscosity data. The most stable geometry of isobutanol–isobutanol, cyclohexylamine–isobutanol, and cyclohexylamine–cyclohexylamine were studied using the density functional theory (DFT) in gases phase. In liquid phase, the molecular dynamics simulations have been performed and used to calculate the densities, mean square displacement (MSD), self-diffusion coefficients,...

Thermodynamic study of the solubility of 2,4′-dihydroxydiphenyl sulfone in nine organic solvents from T = (278.15 to 313.15) K and thermodynamic properties of dissolution

The solubility of 2,4′-dihydroxydiphenyl sulfone in methanol, ethanol, acetone, acetonitrile, ethyl acetate, 1,4-dioxane, n-butanol, isopropanol and 2-butanone was determined at temperatures from (278.15 to 313.15)K under 101.2kPa by using the high-performance liquid chromatography (HPLC). With the increase in temperature, the solubility of 2,4′-dihydroxydiphenyl sulfone in these solvents increased. Generally, the mass fraction solubility followed the sequence from high to low in different solvents except for 1,4-dioxane: acetone>methanol>(2-butanone, ethanol)>isopropanol>n-butanol>ethyl acetate>acetonitrile. The solubility of 2,4′-dihydroxydiphenyl sulfone in 1,4-dioxane showed the strongest positive dependency on temperature. The measured solubility of 2,4′-dihydroxydiphenyl sulfone were correlated by using four thermodynamic models, which corresponded to the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of RMSD and RAD were 9.52×10−4 and 1.54%, respectively. By comparing the four models, the computed solubility using the modified Apelblat equation provided better agreement with the experimental values than those using the other three models. On the whole, the four models were all acceptable for describing the solubility of 2,4′-dihydroxydiphenyl sulfone in the selected solvents. In addition, the standard molar dissolution enthalpy and excess enthalpy of solution of 2,4′-dihydroxydiphenyl sulfone in the solvents were evaluated. The dissolution process of 2,4′-dihydroxydiphenyl sulfone in the selected solvents was endothermic. The study on the solubility of 2,4′-dihydroxydiphenyl sulfone in the selected solvents and solution properties can provide fundamental data in the separating process of 2,4′-dihydroxydiphenyl sulfone from its isomeric mixtures.

Thermodynamics and selectivity of separation based on activity coefficients at infinite dilution of various solutes in 1-allyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide ionic liquid

The effect of interaction between organic solvents or water on the interfacial and bulk properties of 1-allyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide ([AMIM][NTf2]) and on activity coefficients (γ13∞) at infinite dilution for 64 solutes. The observations monitored by gas-liquid chromatography at six temperatures in range of (318.15–368.15)K are explained for polar and non-polar solutes as alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters. Density, ρ and viscosity η as a function of temperature, T for chosen ionic liquid, [AMIM][NTf2] at pressure p=101kPa were measured. The gas-liquid partition coefficients, KL at infinite dilution and the fundamental thermodynamic functions, the partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated. The values of selectivity and capacity for three separation problems as hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene were calculated from γ13∞ and compared to literature values for imidazolium-based or bis{(trifluoromethyl)sulfonyl}imide-based ionic liquids (ILs) for the same separation problems. The data presented here show that [AMIM][NTf2] reveals average selectivity in the comparison to measured earlier ILs in the chosen separation problems. These findings seem useful for future applications of ILs especially for alkanes/alkenes separation process.

Excess enthalpies and excess volumes of binary mixtures containing a linear carboxylic acid + di-iso-propyl ether at 298.15 K and 0.1 MPa

Molar heat of mixing and volume change of mixing, coinciding with molar excess enthalpies, H E, and molar excess volumes, V E, respectively, of binary mixtures composed by a linear saturated aliphatic acid of general formula: CH3(CH2)u-2–CO2H [u = 2, 3, 4, 5, 6, 7, 8] + di-iso-propyl ether, [(CH3)2CH−]2O, have been measured in the whole range of mole fraction at 298.15 K and 0.10 MPa. The H E experimental determinations have been realized by means of a mixing flow calorimetric apparatus, and V E have been calculated from density data acquired by using a vibrating tube densitometer. Mixing is exothermic for all investigated systems. The values at equimolar composition, H x=0.5 E , are in the range: (−385 ± 1 to −140 ± 4) J mol−1. The more negative value is attributable to butanoic acid-containing mixture; then, H E decrease in absolute value as the alkyl chain of the acid increases. For the same systems, the V E trends are different: the value at equimolar composition, V x=0.5 E , always negative, increase regularly in absolute value as the alkyl chain length of the acid increases from –1.12 × 10−6 m3 mol−1 for mixtures containing ethanoic acid to −1.75 × 10−6 m3 mol−1 for octanoic acid-containing mixtures.

Densities, Viscosities, and Refractive Indices of Dimethyl Carbonate + 1-Hexanol/1-Octanol Binary Mixtures at Different Temperatures

The densities, viscosities, and refractive indices for the binary mixtures of dimethyl carbonate (DMC) + 1-hexanol/1-octanol were measured at atmospheric pressure and temperature of 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K over the whole concentration range. Different thermodynamic, transport, and optical properties, such as excess molar volume, partial molar volume, thermal expansion coefficient, isothermal coefficient of pressure excess molar enthalpy, activation energy of flow, excess refractive index, and electronic polarizability were obtained from the experimental data. The results were analyzed in terms of specific molecular interactions and mixing behavior between mixture components with taking into considerations the effect of temperature. Moreover, the thermophysical properties were examined with predictive and correlative equations. The quality of the predictions for the studied systems was evaluated by measuring the deviations and drawing the comparison plots.

Application of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquid for the different types of separations problem: Activity coefficients at infinite dilution measurements using gas-liquid chromatography technique

The present work focussed on application of the environmental friendly 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([BMIM]+[Tf2N]−) ionic liquid for the separations of (alkane/aromatic), (alkane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol) using gas-liquid chromatography (GLC) technique. In this reason the activity coefficients at infinite dilution, γ13∞, for 31 organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatics, alkanol and ketones) and water in ionic liquid were measured at temperatures of (323.15, 333.15, 343.15, 353.15 and 363.15) K. Stationary phase loadings of (42.83 and 68.66) % by mass were used to ensure repeatability of measurements. Density and viscosity values were measured to confirm the purity of ionic liquid. Partial molar excess enthalpies at infinite dilution, ΔH1E,∞, were also determined. The selectivities, Sij∞, and capacities, kj∞, were determined for the above separations. The separating ability of the investigated ionic liquid was compared with previously investigated ionic liquids and industrial solvents such as sulfolane, n-methyl-2-pyrrolidine (NMP) and n-formylmorpholine (NFM).

Measurements of Infinite Dilution Activity Coefficients of Alkanols in the Ionic Liquid Tributylmethylammonium Methyl Sulfate Using HS-SPME/GC/FID

The activity coefficients at infinite dilution (γi∞) and gas–liquid partition coefficients (KLG) for six solutes (methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol) in the liquid ionic (IL) tributylmethylammonium methyl sulfate ([TBMA][CH3SO4]) were determined by HS-SPME (headspace-solid phase micro extraction) at four temperatures from 338.15 to 368.15 K. The values of partial molar excess enthalpies at infinite dilution (ΔHiE,∞), Gibbs free energies (ΔGiE,∞), and entropies (ΔSiE,∞) were also calculated from the γi∞ values. The results are unprecedented in the literature and suggest that SPME can be used to determine activity coefficients at infinite dilution of solutes in liquid ionic solvents.

Separation Based on Limiting Activity Coefficients of Various Solutes in 1-Allyl-3-methylimidazolium Dicyanamide Ionic Liquid

In the present work the limiting activity coefficients (γ13∞) for 65 solutes, including polar and nonpolar solutes as alkanes, alkenes, and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in the 1-allyl-3-methylimidazolium dicyanamide ([AMIM][DCA]) were determined by gas–liquid chromatography at six temperatures in the range of (308.15 to 358.15) K. The gas–liquid partition coefficients, KL at infinite dilution, and the fundamental thermodynamic functions, the limiting partial molar excess Gibbs energy, enthalpy, and entropy, were calculated. The values of selectivity and capacity for three separation problems as hexane/hex-1-ene, cyclohexane/cyclohexene, and ethylbenzene/styrene were calculated from γ13∞ and compared to literature values for imidazolium-based or dicyanamide-based ionic liquids (ILs) for the same separation problems. The data presented here shows that [AMIM][DCA] reveals one of the highest selectivit...

Thermodynamics of aromatic polar compound (alkanone, alkanal or alkanoate) + hydrocarbon mixtures

Liquid-liquid equilibrium (LLE) temperatures have been determined for the mixtures: phenyl acetone + CH3(CH2)uCH3 (u = 8,10,12,14), or + 2,2,4-trimethylpentane, benzyl acetone + decane and benzyl acetate + dodecane by means of the critical opalescence method using a laser scattering technique. All the systems are characterized by an upper critical solution temperature (UCST). The coexistence curves have a rather flat maximum, and become shifted to higher concentrations of phenyl acetone when the alkane size increases. Aromatic alkanone, or alkanal or alkanoate + alkane, or + benzene mixtures have been investigated using DISQUAC. The interaction parameters for the X/aliphatic and X/aromatic contacts (X = CO, CHO, COO) are reported. The model correctly describes experimental data on LLE, vapour-liquid equilibria (VLE) and excess molar enthalpies (HmE). UNIFAC (Dortmund version) results are poorer. This shows that new UNIFAC groups for the mentioned aromatic systems should be defined. Proximity effects depend on the number of CH2 groups (n) between the phenyl ring and the polar group of the aromatic compound considered. Proximity effects lead to enhanced dipolar interactions, which change in the order n = 1 > n = 2 > n = 0. Comparison of thermodynamic properties for systems with isomeric molecules (benzyl ethanoate and phenyl acetone) shows that dispersive interactions are more relevant in the benzyl ethanoate system.

Thermodynamics of amide + ketone mixtures. 1. Volumetric, speed of sound and refractive index data for N,N-dimethylformamide + 2-alkanone systems at several temperatures

Densities, ρ, speeds of sound, c, and refractive indices, nD, have been measured for the systems N,N-dimethylformamide (DMF)+propanone, +2-butanone, or +2-pentanone in the temperature range from (293.15 to 303.15)K and at T=298.15K for the DMF+2-heptanone mixture. Due to the high volatility of acetone, the corresponding nD measurements were developed at T=(293.15 and 298.15)K. The direct experimental data were used to determine the excess molar volumes, VmE, and the excess refractive indices, nDE, at the working temperatures. Values of the excess functions at T=298.15K, for the speed of sound, cE, the isentropic compressibility, κSE and for the excess thermal expansion coefficient, αpE, were also calculated. The investigated systems are characterised by strong (amide+ketone) interactions, which become weaker when the alkanone size is increased. This is supported by negative VmE values; by the dependence on temperature and pressure of VmE, and by positive PintE (excess internal pressure) values. Analysis of the systems in terms of the Rao’s constant indicates that there is no complex formation. In addition, negative VmE values also reveal the existence of structural effects, which largely contribute to the excess molar enthalpy, HmE. VmE and HmE values increase with the chain length of the 2-alkanone. It allows conclude that the relative VmE variation with the ketone size is closely related to that of the interactional contribution to this excess function. Molar refraction values, Rm, show that dispersive interactions become more relevant for the systems including longer 2-alkanones.

Activity coefficients at infinite dilution of organic solvents and water in 1-butyl-3-methylimidazolium dicyanamide. A literature review of hexane/hex-1-ene separation

The work presented focused on the experimental data of the activity coefficients at infinite dilution, (γ13∞) of several solutes in ionic liquid of 1-butyl-3-methylimidazolium dicyanamide, [BMIM][DCA]. The values of γ13∞ for 64 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in [BMIM][DCA] were determined by gas–liquid chromatography at six temperatures in range of (318.15–368.15) K. The gas–liquid partition coefficients were calculated for all solutes. The partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated from the experimental γ13∞ values. The [BMIM][DCA] was discussed as a solvent for the different types of separation problems with special attention to the separation of hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene. This work discuss a particular type of mixture made up of small hydrocarbons (alkanes) and their unsaturated counterparts (alkenes). The separating ability of the investigated ionic liquid was compared with the previously investigated 1-butyl-3-methylimidazolium-based, and dicyanoamide-based ILs for three chosen separation problems. Additionally, a literature review of γ13∞ for the hexane/hex-1-ene separation problem at T = 323.15 K is presented for the years 2010–2015. It was found that several ILs may replace conventional solvents. The proposed [BMIM][DCA] may be used as an alternative solvent for the separation of alkenes from alkanes.

A 1-alkylcyanopyridinium-based ionic liquid in the separation processes

The activity coefficients at infinite dilution, γ13∞ for 65 solutes, including wide spectra of alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in the 1-butyl-4-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide [BCN4Py][NTf2] were determined by gas–liquid chromatography for all solutes at seven temperatures in range of (308.15 to 368.15)K. The gas–liquid partition coefficients, KL at infinite dilution and the fundamental thermodynamic functions, the partial molar excess Gibbs energy, ΔG1E,∞, enthalpy ΔH1E,∞, and entropy term TrefΔS1E,∞ were calculated. The values of selectivity and capacity for four separation problems as hexane/hex-1-ene, hexane/benzene, cyclohexane/cyclohexene and ethylobenzene-styrene were calculated from γ13∞ and compared to literature values for bis{(trifluoromethyl)sulfonyl}imide-based ionic liquids (ILs) for the same separation problems. In comparison with the former measured ILs, the [BCN4Py][NTf2] present quite high selectivity for the chosen separation problems, and an average capacity for hex-1-ene, benzene, cyclohexene and styrene. The data presented here shows that [BCN4Py][NTf2] may be proposed as an alternative solvent for the chosen separation problems in new technological projects.

Vapor–Liquid Equilibria, Excess Enthalpy, and Density of Aqueous γ-Valerolactone Solutions.

Thermodynamic measurements were made for the binary mixture of water + γ-valerolactone (GVL) and for pure GVL to facilitate the development of the technology of lignin removal from lignocellulosic biomass (Fang, W.; Sixta, H. Advanced Biorefinery based on the Fractionation of Biomass in γ - Valerolactone and Water. ChemSusChem 2015, 8, 73−76). The density and vapor pressure of pure GVL as a function of temperature were measured and correlated for a wide range of the temperatures and pressures. Isothermal vapor–liquid equilibrium (VLE) data of the binary mixture of water + GVL were measured at 350.2 K with a static total pressure apparatus. Absence of an azeotrope was confirmed by circulation still measurements with diluted GVL solutions. Excess molar enthalpy (hE) of the mixture for the whole range of mole fractions including infinite dilution was measured using a SETARAM C80 calorimeter equipped with a flow mixing cell at 322.6 and 303.2 K. The VLE and hE data were used for the optimization of UNIQUAC an...