Partial Molar Excess Enthalpies Research Articles

Separation of binary mixtures based on gamma infinity data using [OMMIM][NTf 2 ] ionic liquid and modelling of thermodynamic functions

Abstract Activity coefficients at infinite dilution ( γ i ∞ ) and (gas-liquid) partition coefficients ( K L ) for organic compounds (alkanes, alkenes, alkyl benzenes, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, 1,4-dioxane, chloromethanes, and alcohols) in the ionic liquid (IL) 1-octyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ([OMMIM][NTf2]) have been measured by the gas-liquid chromatographic(GLC) method in the temperature range of (313.15 to 353.15) K. Density, ρ as a function of temperature for [OMMIM][NTf2] at pressure p = 101.3 kPa were measured. The values of the partial molar excess enthalpies at infinite dilution ( H ¯ i E , ∞ ) were derived from the temperature dependence of the γ i ∞ values. The entropies ( T r ef S ¯ i E , ∞ ) and Gibbs energies ( G ¯ i E , ∞ ) of organic solutes in [OMMIM][NTf2] at a reference temperature T r ef = 298.15 K were also calculated from the γ i ∞ values. The Hildebrand’s solubility parameters of the IL [OMMIM][NTf2] were also determined by the regular solution theory (RST) combined with Flory “combinatorial” equation. The linear free energy relationship (LFER) analysis of the results was performed to disclose molecular interactions operating between the IL and the individual solutes. Selectivity ( S i j ∞ ) and capacity ( k j ∞ ) at infinite dilution at 323.15 K have been determined for n-hexane ( i )/benzene ( j ), cyclohexane ( i )/benzene ( j ) and compared to literature values for [NTf2]-based ILs for the same separation problems. For three isomeric xylenes separation problems, S i j ∞ at 323.15 K was also obtained from the γ i ∞ values.

Separation of binary mixtures hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene based on gamma infinity data measurements

Abstract The activity coefficients γ 13 ∞ at infinite dilution for 64 solutes were determined in the 1-(3-hydroxypropyl)-3-methylimidazolium dicyanamide, [N-C3OHMIM][DCA] and 58 solutes in (3-hydroxypropyl)-1-methylmorpholinium dicyanamide, [N-C3OHMMor][DCA] using the gas-liquid chromatography technique. Measurements were undertaken at six temperatures, in 10 K intervals, in the range of (298.15–368.15) K. The solutes studied included both non-polar and polar compounds, as alkanes, alkenes, and alkynes, as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters. Density, ρ, measurements for a range of temperatures (298.15–368.15) K for the synthesized, new ionic liquids (ILs) were also undertaken at pressure, p = 101 kPa. The gas-liquid partition coefficients, K L at infinite dilution, and the fundamental thermodynamic functions, partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated from the experimental data measurements. The values of selectivity and capacity for three separation cases, viz. hexane/hex-1-ene, cyclohexane/cyclohexene, and ethylbenzene/styrene were calculated from γ 13 ∞ values and compared to literature for imidazolium-based, morfolinium-based, or dicyanamide-based, ILs. The results from the study indicate that [N-C3OHMIM][DCA] has large selectivity values for all three of the separation cases studied and that [N-C3OHMMor][DCA] has the largest selectivity ever noted for cyclohexane/cyclohexene, and ethylbenzene/styrene separation processes.

Separation of water/butan-1-ol based on activity coefficients at infinite dilution in 1,3-didecyl-2-methylimidazolium dicyanamide ionic liquid

The activity coefficients (γ13∞) at infinite dilution for 65 solutes and the effect of interaction between organic solvents or water on the interfacial and bulk properties of 1,3-didecyl-2-methylimidazolium dicyanamide, [D2MIM][DCA] were detected by the gas-liquid chromatography at six temperatures in range of (358.15–408.15) K. The data are provided for polar and non-polar solutes as alkanes, alkenes and alkynes, aromatic hydrocarbons, alcohols, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, esters as well as for water. The synthesis and the thermal properties of [D2MIM][DCA] are presented. The fundamental thermodynamic functions, the partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated and discussed. The values of selectivity and capacity for the separation problem water/butan-1-ol were calculated from γ13∞ and compared to literature values for imidazolium-based, or dicyanamide-based ionic liquids (ILs) for the same separation problem. The data presented here shows that [D2MIM][DCA] reveals attractive selectivity and capacity in the comparison to measured earlier ILs in the chosen separation problem. These findings seem useful for future applications of this IL in projects of new technologies for water/butan-1-ol separation process.

Cluster formation and percolation in ethanol-water mixtures

Results of systematic molecular dynamics studies of ethanol-water mixtures, over the entire concentration range, were reported previously that agree with experimental X-ray diffraction data. These simulated systems are analyzed in this work to examine cluster formation and percolation, using four different hydrogen bond definitions. Percolation analyses revealed that each mixture (even the one containing 80mol% ethanol) is above the 3D percolation threshold, with fractal dimensions, df, between 2.6 and 2.9, depending on concentration. Monotype water cluster formation was also studied in the mixtures: 3D water percolation can be found in systems with less than 40mol% ethanol, with fractal dimensions between 2.53 and 2.84. These observations can be put in parallel with experimental data on some thermodynamic quantities, such as the excess partial molar enthalpy and entropy.

Thermodynamics and activity coefficients at infinite dilution for organic compounds and water in the ionic liquid 1-butyl-3-methylimidazolium perchlorate

Activity coefficients at infinite dilution (γi∞) and (gas–liquid) partition coefficients (KL) for organic compounds (alkanes, alkenes, alkyl benzenes, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, 1,4-dioxane, chloromethanes, and alcohols) and water in the ionic liquid (IL) 1-butyl-3-methylimidazolium perchlorate ([BMIM][ClO4]) have been measured by the (gas-liquid) chromatographic method in the temperature range of (303.15–353.15)K. Density, ρ as a function of temperature for [BMIM][ClO4] at pressure p=101.3kPa were measured. The values of the partial molar excess enthalpies at infinite dilution (H¯iE,∞) were derived from the temperature dependence of the γi∞ values. The entropies (TrefS¯iE,∞) and Gibbs free energies (G¯iE,∞) of organic solutes in [BMIM][ClO4] at a reference temperature Tref=298.15K were also calculated from the γi∞ values. The Hildebrand’s solubility parameters of the IL [BMIM][ClO4] were also determined by the regular solution theory (RST) combined with Flory ‘‘combinatorial’’ equation. 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 values for 1-buthyl-3-methylimidazolium-based ionic liquids (ILs) for the same separation problems. For three isomeric xylenes separation problems, selectivity at 323.15K were also obtained from the γi∞ values.

Measurement of Activity Coefficients at Infinite Dilution for Alcohols in [BMIM][CH3SO4] using HS-SPME/GC-FID

ABSTRACT The activity coefficient at infinite dilution (&IN1) and distribution ratios at infinite dilution (&IN2) were determined for alkanols (methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol) in the ionic liquid (IL) 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][CH3SO4]) by HS-SPME (Headspace - Solid Phase Micro Extraction) at four temperatures (298.15, 313.15, 333.15, and 353.15K) using headspace - solid phase microextraction (SPME-HS). The results showed significant agreement with literature data. In addition, partial molar excess enthalpies at infinite dilution (&IN3), excess Gibbs energies (&IN4), and excess entropies (&IN5) were calculated from the (&IN6) values.

Separation of water/butan-1-ol mixtures based on limiting activity coefficients with phosphonium-based ionic liquid

In the present work the limiting activity coefficients (γ13∞) for 64 solutes, including 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 in the tributyltetradecylphosphonium dodecylbenzenesulfonate, [P14,4,4,4][DBS] were determined by gas-liquid chromatography at six temperatures in range of (318.15–368.15) K. Density, ρ as a function of temperature, T for chosen ionic liquid, [P14,4,4,4][DBS] at pressure p=101kPa was measured. 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 water/butan-1-ol separation problem were calculated from γ13∞ and compared to literature values for phosphonium-based or other selected ionic liquids for the same separation problem. The Abraham solvation parameter model was also presented for all solutes. On the bases of the results the intermolecular interactions of the chosen IL and solutes were discussed. The data presented here shows that [P14,4,4,4][DBS] reveals the best ever measured selectivity and capacity for the for water/butan-1-ol separation.

High selective water/butan-1-ol separation on investigation of limiting activity coefficients with [P8,8,8,8][NTf2] ionic liquid

The limiting activity coefficients (γ13∞) for 65 solutes, including polar and non-polar solutes as alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, esters and water in the tetraoctylphosphonium bis{(trifluomethyl)sulfonyl}imide ionic liquid (IL), [P8,8,8,8][NTf2] were determined by gas-liquid chromatography at six temperatures in range of (318.15–368.15) K. The synthesis and DSC data are presented for this IL. Density, ρ and viscosity, η as a function of temperature, T in a range of (298.15–398.15) K for [P8,8,8,8][NTf2] were measured at pressure p = 101 kPa. The gas-liquid partition coefficients, KL at infinite dilution and the thermodynamic functions, the limiting partial molar excess Gibbs energy, enthalpy and entropy were calculated. The values of selectivity and capacity for water/butan-1-ol separation problem were calculated from γ13∞ and compared to literature values for phosphonium-based or other selected ionic liquids for the same separation problem. The Abraham solvation parameter model was also presented for all solutes. On the basis of the results, the intermolecular interactions of the chosen IL and solutes were discussed. The data presented here show that [P8,8,8,8][NTf2] reveals very large selectivity for the water/butan-1-ol separation.

Thermal and Volumetric Properties of Some C5 and C6 Alkanones at Infinite Dilution in Water

Precise measurements of excess enthalpies and densities of highly dilute aqueous solutions of five C5–C6 alkanones (namely 2-pentanone, 3-pentanone, 3-methyl-2-butanone, 2-hexanone, and 4-methyl-2-pentanone) were carried out using tandem flow mixing calorimetry and vibrating-tube densimetry. The experimental data obtained in the temperature range from 288.15 to 318.15 K were utilized for the evaluation of limiting partial molar excess enthalpies, partial molar volumes, and partial molar excess volumes of the alkanones in water. Within the temperature range studied, these infinite dilution properties were found to exhibit linear trends. As inferred from respective linear fits, partial molar excess heat capacities, partial molar expansions, and excess partial molar expansions were obtained with a good accuracy. Moreover, hydration enthalpies and heat capacities of the alkanones studied were evaluated, too. The thermodynamic behavior of the alkanone solutes was discussed in terms of molecular interactions an...

Determination of gas–liquid partition coefficients of several organic solutes in trihexyl(tetradecyl)phosphonium bromide using capillary gas chromatography columns

In this paper, we report gas-liquid partition constants for thirty-five volatile organic solutes in the room temperature ionic liquid trihexyl(tetradecyl)phosphonium bromide measured by gas-liquid chromatography using capillary columns. The relative contribution of gas-liquid partition and interfacial adsorption to retention was evaluated through the use of columns with different the phase ratio. Four capillary columns with exactly known phase ratios were constructed and employed to measure the solute retention factors at four temperatures between 313.15 and 343.15K. The partition coefficients were calculated from the slopes of the linear regression between solute retention factors and the reciprocal of phase ratio at a given temperature according to the gas-liquid chromatographic theory. Gas-liquid interfacial adsorption was detected for a few solutes and it has been considered for the calculations of partition coefficient. Reliable solute's infinite dilution activity coefficients can be obtained when retention data are determined by a unique partitioning mechanism. The partial molar excess enthalpies at infinite dilution have been estimated from the dependence of experimental values of solute activity coefficients with the column temperature. A thorough discussion of the uncertainties of the experimental measurements and the main advantages of the use of capillary columns to acquire the aforementioned relevant thermodynamic information was performed.

Separation of binary mixtures hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene based on limiting activity coefficients

The measurements of a limiting activity coefficients, γ13∞ at infinite dilution for 63 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-(3-hydroxypropyl)pyridinium dicyanamide, [N-C3OHPY][DCA], determined by gas-liquid chromatography at temperature range of (298.15–368.15)K are developed. The synthesis and thermochemical characteristic of the ionic liquid (IL) is described. The density and viscosity of the IL was measured as a function of temperature in a range of (298.15–368.15) K. The comparison of γ13∞ for selected solutes in ionic liquids (ILs) with [N-C3OHPY]+ cation and [TCM]−, [DCA]−, [TCB]− and [SCN]−-anions at one temperature, T=328.15K is shown. The gas-liquid partition coefficients, KL at infinite dilution and the limiting fundamental thermodynamic functions, the partial molar excess Gibbs energy, enthalpy and entropy were calculated for all solutes. The values of selectivity and capacity for three separation problems hexane/hex-1-ene, cyclohexane/cyclohexene and methylbenzene/styrene were calculated from γ13∞ and compared to literature values for [N-C3OHPY]-based or [DCA]-based ILs for the same separation problems. The data presented here shows that [N-C3OHPY][DCA] reveals large selectivity 2.34, 2.79 and 2.27 in three of discussed separation problems. However, the comparison to the measured earlier [DCA]-based ILs shows the low capacity for the hex-1-ene and cyclohexene. The Abraham solvation parameter model was also presented for all solutes. On the bases of the results the intermolecular interactions of the chosen IL and solutes was discussed.

Excess molar enthalpies of ethane-1,2-diamine plus primary and secondary alkanols (C1–C4) and correlation with Redlich-Kister, Wilson, NRTL and UNIQUAC models at T = 298 K

Excess molar enthalpies, HmE of binary mixtures of ethane-1,2-diamine (EDA) 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 atmospheric pressure (81.5kPa) with a Parr 1455 solution calorimeter. All the binary mixtures showed exothermic behavior over the entire range of compositions. From the experimental results, the excess partial molar enthalpies, HiE and excess partial molar enthalpies at infinite dilution, HiE,∞ were calculated. Excess molar enthalpies, HmE values increase as the chain length of the alkanol is increased, showing minimum values varying from −4395 (methanol) to −1987 J·mol-1 (butan-2-ol). The minimum HmE values were observed about 0.4mol fraction of ethane-1,2-diamine (EDA). The experimental results were discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules. Finally the experimental results were correlated by the Redlich–Kister equation and the three thermodynamic models (Wilson, NRTL, and UNIQUAC) based on the local composition theory.

Excess molar enthalpies of dichloromethane +acetone or + dimethyl sulfoxide or + tetrahydrofuran or + 1, 4-dioxane at the temperature 313.15 K

Excess molar enthalpies HE at T= 313.15 K have been determined for dichloromethane (CH2Cl2) + acetone (CH3)2CO or + dimethyl sulfoxide (CH3)2SO) (DMSO) or + tetrahydrofuran (C4H8O) or + 1, 4-dioxane (C4H8O2). The excess molar enthalpies for all systems are exothermic in nature. The excess partial molar enthalpies of the components HEm, 1, and HEm, 2 were calculated from HE data. These results indicate the existence of specific interactions between all these components.

Thermodynamic properties of five biofuel-relevant compounds at infinite dilution in water

In this work, thermodynamic behavior of five biomass-derived compounds, namely furfural, 2-methylfuran, 2,5-dimethylfuran, methyl vinyl ketone, and allyl alcohol, in highly dilute aqueous solutions has been experimentally investigated. Using the inert gas stripping technique, their air-water partition coefficients (Kaw) and limiting activity coefficients γ1∞ were measured at several temperatures in the range from (273 to 333) K. Except for the furans, infinite dilution partial molar excess enthalpies and volumes were further determined as functions of temperature from (288 to 318) K by tandem flow mixing calorimetry and vibrating-tube densimetry, which in turn allowed reliable derivation of respective heat capacities and expansivities. In addition, densities of all five pure liquids and viscosities of furfural and allyl alcohol were also measured in the range from (288 to 318) K. For each compound, the vapor-liquid equilibrium and (when measured) calorimetric data of this work together with some relevant data reported previously in the literature were simultaneously correlated by a three-parameter model equation providing adequate simultaneous description of all information involved. As a result, recommended thermodynamically consistent temperature dependences of Kaw and γ1∞ of superior accuracy were thus established in the range from the melting point to the normal boiling point of water. The variation of Kaw and γ1∞ with temperature and solute molecular structure along with related energetic functions of dissolution and hydration of the examined compounds were overviewed and briefly discussed.

Separation of binary mixtures based on gamma infinity data using [EMIM][TCM] ionic liquid and modelling of thermodynamic functions

The measurements of activity coefficients γ13∞ at infinite dilution for 64 solutes including water is presented for 1-ethyl-3-methylimidazolium tricyanomethanide, [EMIM][TCM] ionic liquid (IL). The data obtained by gas-liquid chromatography at six temperatures at 10K intervals in range of (318.15 to 368.15) K are presented for non-polar and polar solutes as alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters. The comparison of γ13∞ at one temperature, T=328.15K for selected solutes in ionic liquids (ILs) with [EMIM]+ cation and [TCM]−, [DCA]−, [TCB]− and [SCN]− -anions is presented. 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 are calculated for all solutes. The values of selectivity and capacity for three separation problems such as hexane/hex-1-ene, cyclohexane/cyclohexene and methylbenzene/styrene are calculated from γ13∞ and compared to literature values for [EMIM]-based or [TCM]-based ILs for the same separation problems. The data presented here shows that [EMIM][TCM] reveals large selectivity 2.35, 2.24, and 2.01 in three of discussed separation problems, hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene. The comparison to the measured earlier [TCM]-based ILs shows the lowest capacity for the hexane/hex-1-ene separation problem. The Abraham solvation parameter model is also discussed. Present study discusses the intermolecular interactions of the chosen IL and solutes and may be of considerable importance for selection of optimum entrainer for the desired three separation processes.

The effect of 2,2,2-trifluoroethanol on water studied by using third derivatives of Gibbs energy, G

We determined the excess partial molar enthalpy and the excess partial molar volume, HTFEE, VTFEE, of 2,2,2-trifluoroethanol (TFE) in TFE-H2O at 25.0°C. We then evaluate the TFE-TFE interactions in terms of enthalpy and volume, HTFE-TFEE and VTFE-TFEE, graphically without resorting to any model dependent fitting functions. Both model-free third derivatives indicate that TFE is a hydrophobic solute and that as other hydrophobic alkyl mono-ols there are three distinct mixing schemes, Mixing Schemes I, II, and III in their aqueous solutions. The relative strength in hydrophobicity between TFE and tert-butylalcohol (TBA), for example, gave a mixed message within the behavior of these third derivative quantities. We thus applied the 1-propanol (1P) probing methodology (Koga, Y. Phys. Chem. Chem. Phys. 2013, 15, 14548) that utilizes the fourth derivative in effect, and quantified the degree of hydrophobicity of TFE. It turned out that TFE is a stronger hydrophobe than 1P and ethanol (ET), and has approximately the same hydrophobicity as TBA within the estimated uncertainty. These findings were compared with the ability reported in literature to denature β-lactoglobulin and to induce α-helices in melittin in their aqueous solutions.

Partial molar enthalpies of organic solutes in the ionic liquid [EMIM][EtSO4

Partial molar excess enthalpies of mixing of the organic liquids methanol, acetonitrile, acetone and propan-1-ol in 1-ethyl-3-methylimidazolium ethyl sulfate ([EMIM][EtSO4]) have been measured using a titration calorimeter. Data have been obtained at 298K, in the case of methanol also at 308K, in the mole fraction range of the organic liquid x2 from 0.005 to 0.05. The results have been extrapolated to infinite dilution for determining enthalpies of dilution at infinite concentrations H¯2,∞E (x2=0). Alternatively values of H¯2,∞E can be obtained from measurements of activity coefficients γ2∞ at different temperatures using the gas chromatographic or the dilutor technique. However, according to our error analysis calorimetric results of H¯2E,∞ are by a factor 2–3 more reliable than the results obtained by the indirect methods.

Use of HS-SPME for analysis of the influence of salt concentration and temperature on the activity coefficient at infinite dilution of ethanol-water-salt systems

Accurate knowledge of thermodynamic properties is of great importance in optimizing industrial processes of chemical separation. However, traditional techniques have limitations that hinder the use in complex systems, especially involving strong electrolytes. Solid phase micro-extraction (SPME) was used to determine infinite dilution activity coefficients of ethanol in water-salt systems. Different concentrations of inorganic salts were used to verify the influence on the activity coefficient at temperatures of 323.15, 333.15, 343.15, and 353.15 K. Salts evaluated in SPME include potassium chloride (KCl), calcium chloride (CaCl2), and aluminum chloride (AlCl3) at concentrations of 1.125, 1.800, and 2.571 mol/Kg. Comparisons between data obtained using SPME and the theoretical basis and literature data showed good agreement. Thermodynamic parameters such as partial molar excess enthalpy at infinite dilution, partial molar excess entropy at infinite dilution, and partial molar excess Gibbs energy were calculated from the infinite dilution activity coefficient. AlCl3 produced the highest activity coefficient for ethanol at infinite dilution, indicating a strong influence on the separation of ethanol. The results obtained indicate that SPME technique can be considered an alternative method on determination of activity coefficients at infinite dilution.

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 \( H_{{I{\text{L - IL}}}}^{\text{E}} \).

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).