Experimental enthalpies of mixtures of alkylfluoroethers + n-alkanes at 298.15 K

In this work, excess molar enthalpies, H_m^E, at 298.15 K and atmospheric pressure of methylnonafluorobutylether + alkane (hexane, octane, decane, dodecane) and ethylnonafluorobutylether + alkane (hexane, octane, decane, dodecane) are reported. Values of excess molar enthalpies were measured using a Calvet microcalorimeter. The binary experimental data were fitted using a Redlich–Kister variable-degree polynomial. The excess molar enthalpy is positive for all the mixtures. Phase separation is found in the range of 0.3<x<0.8 and 0.3<x<0.94 for the mixtures methylnonafluorobutyl ether + (decane, or dodecane), respectively.     

Experimental and theoretical study of quaternary (liquid + liquid) equilibria for mixtures of (methanol or water + ethanol + toluene + n-decane)

Experimental (liquid + liquid) equilibrium data were obtained for the extraction of toluene from n-decane by mixed-solvents (ethanol + water) and (ethanol + methanol) at three temperatures (298.15, 303.15, and 313.15) K and ambient pressure.The measured tie-line data for two quaternary mixtures of {(ethanol +  water) + toluene + n-decane} and {(ethanol + methanol) + toluene + n-decane} are presented. The experimental quaternary (liquid + liquid) equilibrium data have been correlated using the NRTL activity coefficient model to obtain the binary interaction parameters of these components. The NRTL models predict the equilibrium compositions of the quaternary mixtures with small deviations. The partition coefficients and the selectivity factor of the mixed-solvents used were calculated and presented. From our experimental and calculated results, we conclude that for the extraction of toluene from n-decane mixtures the mixed-solvent (ethanol + methanol) has a higher selectivity factor than the other mixed-solvent at the three temperatures studied.     

Ternary and quaternary (liquid + liquid) equilibria for (water + ethanol + α-pinene, +β-pinene,or +limonene) and (water + ethanol + α-pinene + limonene) at the temperature 298.15 K

(Liquid + liquid) equilibria and tie-lines for the ternary (water + ethanol + α-pinene, or β-pinene or limonene) and quaternary (water + ethanol + α-pinene + limonene) mixtures have been measured at T = 298.15 K. The experimental multicomponent (liquid + liquid) equilibrium data have been successfully represented in terms of the modified UNIQUAC model with binary parameters.     

(Liquid + liquid) equilibria for mixtures of dodecane and ethanol with alkylsulfate-based ionic liquids

The ternary (liquid + liquid) equilibrium (LLE) data for mixtures of dodecane (C₁₂H₂₆) and ethanol with ionic liquids 1,3-dimethylimidazolium methylsulfate [Mmim][MeSO₄], 1-ethyl-3-methylimidazolium methylsulfate, [Emim][MeSO₄] and 1-butyl-3-methylimidazolium methylsulfate, [Bmim][MeSO₄], were studied at T = 298.15 K and 0.101 MPa. The selectivity and solute distribution coefficient ratios determined from the data were used to examine the possibility of using these ionic liquids for extraction of ethanol from dodecane. The temperature dependency was investigated by measuring the LLE data for {dodecane + ethanol + [Mmim][MeSO₄]} at T = 313.15 K and 0.101 MPa. The Othmer–Tobias and Hand equations were used to test the consistency of the tie-line data. The tie-line data were correlated with the Non-Random Two Liquid (NRTL) equation which provided a good model and representation for the experimental results.     

Excess volumes of mixing in (N,N-dimethylacetamide + methanol + water) and (N,N-dimethylacetamide + ethanol + water) at the temperature 313.15 K

Precise excess volumes of mixing measurements at T = 313.15 K are reported over the whole composition range for binary mixtures: (N,N-dimethylacetamide + water), (N,N-dimethylacetamide + methanol), (N,N-dimethylacetamide + ethanol) and for the ternary mixtures (N,N-dimethylacetamide + methanol + water) and (N,N-dimethylacetamide + ethanol + water). For all the systems, large negative deviations from ideality are observed. The binary results have been fitted using the Redlich–Kister type polynomial. The possibility of predicting the ternary results from the binary ones was examined.     

(Vapour + liquid) equilibrium in (N,N-dimethylacetamide + ethanol + water) at the temperature 313.15 K

Total vapour pressures, measured at the temperature 313.15 K, are reported for the ternary mixture (N,N-dimethylacetamide + ethanol + water), and for binary constituent (N,N-dimethylacetamide + ethanol). The present results are also compared with previously obtained data for (amide + ethanol) binary mixtures, where amide = N-methylformamide, N,N-dimethylformamide, N-methylacetamide, 2-pyrrolidinone, and N-methylpyrrolidinone. We found that excess Gibbs free energy of mixing for binary (amide + ethanol) mixtures varies roughly linearly with the molar volume of amide.     

Effect of temperature on the excess molar volumes of some alcohol + aromatic mixtures and modelling by cubic EOS mixing rules

Densities of the (methanol + benzene), (ethanol + benzene), (methanol + chlorobenzene) and (ethanol + chlorobenzene) mixtures have been measured at six temperatures (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15 K) and 101.33 kPa. Excess molar volumes V^E were determined and fitted by the Redlich–Kister equation. It was observed that in all cases V^E increases with rising of temperature. The values of limiting excess partial molar volumes have been calculated, as well. The obtained results have been analysed in terms of specific molecular interactions present in these mixtures taking into considerations effect of temperature on them. The correlation of V^E binary data was performed with the Peng–Robinson–Stryjek–Vera cubic equation of state (PRSV CEOS) coupled with the van der Waals (vdW1) and CEOS/G^E mixing rule introduced by Twu, Coon, Bluck and Tilton (TCBT). The experimental values of V^E were compared with those estimated by both mixing rules at the temperature range and on each temperature, separately.     

Viscosity,density, interfacial tension and compositional data for near critical mixtures of methane + butane and methane + decane systems at 310.95 K

Single- and two-phase binary mixtures of near critical methane + butane and methane + decane systems have been investigated at 310.95 K. A capillary tube viscometer was used to measure the viscosity and a high-pressure densitometer was employed for density measurements. The mixture was prepared gravimetrically and a direct sampling system was used to measure the composition of equilibrium phases in the two-phase region by gas chromatography. The meniscus height technique was used to generate the interfacial tension data.     

(Vapor-liquid) equilibria and excess Gibbs free energy functions of (ethanol + glycerol), or (water + glycerol) binary mixtures at several temperatures

The vapor pressures of (ethanol + glycerol) and (water + glycerol) binary mixtures were measured by means of two static devices at temperatures between (273 and 353 (or 363)) K. The data were correlated with the Antoine equation. From these data, excess Gibbs free energy functions (G^E) were calculated for several constant temperatures and fitted to a fourth-order Redlich–Kister equation using the Barker method. The (ethanol + glycerol) binary system exhibits positive deviations in G^E where for the (water + glycerol) mixture, the G^E is negative for all temperatures investigated over the whole composition. Additionally, the NRTL, UNIQUAC and Modified UNIFAC (Do) models have been used for the correlation or prediction of the total pressure.     

Comparative experimental and modeling studies of the viscosity behavior of ethanol + C7 hydrocarbon mixtures versus pressure and temperature

The viscosity of the binary system ethanol + n-heptane has been measured with a falling-body viscometer for seven compositions as well as for the pure compounds in the temperature range 293.15–353.15 K and up to 100 MPa with an experimental uncertainty of ±2%. At 0.1 MPa, the viscosity has been measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of ±1%. A total of 208 experimental data points are reported. The viscosity behavior of this binary system is interpreted as the results of changes in the free volume, and the breaking or weakening of hydrogen bonds. The excess activation energy for viscous flow of the mixtures is negative with a maximum absolute value of 0.3 kJ mol⁻¹, indicating a very weakly interacting system. The data of this binary system as well as those recently measured for ethanol + toluene have been used to study the performance of some viscosity models with a physical and theoretical background. The evaluated models are based on the hard-sphere scheme, the concepts of the free-volume and the friction theory, and a model derived from molecular dynamics. In addition to these models, the simple compositional models by Grunberg–Nissan and Katti–Chaudhri have also been applied. Overall a satisfactory representation of the viscosity of these two binary ethanol + C₇ hydrocarbon systems is found for the different models within the considered T, P range taking into account their simplicity.     

Phosphoric-based ionic liquids as solvents to separate the azeotropic mixture of ethanol and hexane

Ethanol and hexane mixtures are present in industrial processes producing oxygenated additives for unleaded gasoline. The separation of ethanol and hexane is important but challenging due to the formation of an azeotropic mixture. This research focuses on the study of phosphoric-based ionic liquids (ILs) as green solvents for the separation of ethanol from hexane in a liquid extraction process. The knowledge of the (liquid + liquid) equilibrium (LLE) of this mixture is essential for the design of the extraction separation technique. Hence, the experimental determination of the LLE data for the ternary system {ethanol + hexane + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])}, {ethanol + hexane + 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP])} and {ethanol + hexane + 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP])} at T = 303.2 K and atmospheric pressure was carried out. The reliability of the experimental LLE data was confirmed by applying the Othmer–Tobias and Hand equations, and the NRTL model was used to correlate the experimental results for the studied ternary system. The solute distribution ratio and selectivity, derived from the experimental LLE data, were calculated and analyzed evaluate the capacity of the investigated ILs as solvents in liquid extraction process. This capacity was also compared with that of other ILs. The experimental results show that the studied ILs can be suitable solvents in a (liquid + liquid) extraction for the separation of azeotropic mixtures of ethanol and hexane.     

Liquid–liquid equilibria for n-alkanes (C12, C14, C17) + propylbenzene + NMP mixtures at temperatures between 298 and 328 K

Liquid–liquid equilibria for three ternary systems: dodecane, or tetradecane, or heptadecane + propylbenzene + NMP was studied over a temperature range of 298–328 K. The three systems studied exhibit type I liquid–liquid phase diagram. The effect of temperaure and n-alkane chain length upon solubility, selectivity, and distribution coefficient were investigated experimentally. The experimental results were regressed to estimate the interaction parameters between each of the three pairs of components for the UNIQUAC and the NRTL models as a function of temperature. Both models satisfactorily correlate the experimental data, however the UNIQUAC fit was slightly better than that obtained with the NRTL model. The values of distribution coefficient and selectivity were predicated from the equilibrium data.     

Phase equilibrium properties of binary aqueous solutions of benzylamine, 1,2-bis(2-aminoethoxy)ethane,or 2-[2-(dimethylamino)ethoxy]ethanol

The vapour pressures of (benzylamine + water), {1,2-bis(2-aminoethoxy)ethane + water}, or {2-[2-(dimethylamino)ethoxy]ethanol + water} binary mixtures, and pure 2-[2-(dimethylamino)ethoxy]ethanol component were measured by means of two static devices at temperatures between (283.15 and 363.15 (or 323.15)) K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (G^E) were calculated for several constant temperatures and fitted to a fourth-order Redlich–Kister equation using the Barker’s method. The (benzylamine + water) binary mixture exhibits positive deviations in G^E for (303.15 < T/K < 323.15) and a sinusoidal shape in G^E for T > 323.15 K over the whole composition range. The aqueous 1,2-bis(2-aminoethoxy)ethane or {2-[2-(dimethylamino)ethoxy]ethanol + water} solutions exhibit negative deviations in G^E for all investigated temperatures over the whole composition range.     

Equilibrium solubility of sodium 2-naphthalenesulfonate in binary (sodium chloride + water), (sodium sulfate + water), and (ethanol + water) solvent mixtures at temperatures from (278.15 to 323.15) K

The equilibrium solubility of sodium 2-naphthalenesulfonate in binary (sodium chloride + water), (sodium sulfate + water), and (ethanol + water) solvent mixtures was measured at elevated temperatures from (278.15 to 323.15) K using a steady-state method. With increasing temperatures, the solubility increases in aqueous solvent mixtures. The results of these results were regressed by a modified Apelblat equation. The dissolution entropy and enthalpy determined using the method of the least-squares and the change of Gibbs free energy calculated with the values of Δ_diffS^o and Δ_diffH^o at T = 278.15 K.     

Isobaric vapor–liquid equilibria for mixtures of acetone,ethanol, and 2,2,4-trimethylpentane at 101.3 kPa

Isobaric vapor–liquid equilibrium (VLE) data were determined at the pressure of 101.3 kPa for binary and ternary systems composed of acetone, ethanol, and 2,2,4-trimethylpentane (isooctane). Minimum boiling azeotropes were found in the acetone + 2,2,4-trimethylpentane and ethanol + 2,2,4-trimethylpentane systems. Azeotropic behavior was not found for the ternary system. Thermodynamic consistency tests were performed for all VLE data. The activity coefficients of the binary mixtures were satisfactorily correlated as function of the mole fraction using the Wilson, NRTL, and UNIQUAC models. The models with their best-fitted parameters were used to predict the ternary vapor–liquid equilibrium. The Wilson model appears to yield the best prediction in boiling temperatures.     

Density and surface tension variation with temperature for n-nonane + 1-hexanol

New experimental densities and surface tensions for n-nonane + 1-hexanol at 288.15, 298.15 and 308.15 K are reported. Densities were measured with an Anton Paar DMA 4500 densimeter, and surface tensions using a Lauda TVT2 automated tensiometer, which uses the principle of the pending drop volume. The experimental data of pure liquids and mixtures have been used to calculate excess molar volumes and surface tension deviations of n-nonane + 1-hexanol as a function of mole fractions. A comparative study of these properties together with those available in the literature for the n-alkane + 1-alkanol mixtures has been performed. In addition, the magnitude of these experimental quantities is discussed in terms of the nature and type of intermolecular interactions in binary mixtures.     

Vapour pressure measurement for binary and ternary systems containing water methanol ethanol and an ionic liquid 1-ethyl-3-ethylimidazolium diethylphosphate

Vapour pressure data were measured for three binary systems containing water, methanol or ethanol with an ionic liquid (IL) 1-ethyl-3-ethylimidazolium diethylphosphate([EEIM][DEP]) and for three ternary systems, i.e. (water + ethanol + [EEIM][DEP]), (water  + methanol + [EEIM][DEP]), and (ethanol + methanol + [EEIM][DEP]), at varying temperature and IL-content ranging from mass fraction of 0.10 to 0.85 by a quasi-static method. The vapour pressure data of the binary systems were correlated by NRTL equation with average absolute relative deviation (ARD) within 0.0091. The binary NRTL parameters were used to predict the vapour pressure of the ternary systems (ethanol + water + [EEIM][DEP]), (water + methanol + [EEIM][DEP]), and (ethanol +  methanol + [EEIM][DEP]) with an overall ARD of 0.037 and the maximum deviation of −0.1295. The results indicate that ionic liquid [EEIM][DEP] can give rise to a negative deviation from the Raoult’s law for the solvents of water, methanol and ethanol, but to a varying degree leading to the variation of relative volatility of a solvent and even removal of azeotrope for (water + ethanol).     

Vapor–liquid equilibrium of methane and methane + nitrogen and an equimolar hexane + decane mixture under isothermal conditions

Experimental vapor–liquid equilibrium data of the ternary system composed of methane and an equimolar hexane + decane mixture are reported. The experimental measurements were carried out under isothermal conditions at 258, 273, and 298 K in the pressure range 1–19 MPa. Also, experimental vapor–liquid measurements were carried out for the quaternary system methane + nitrogen and an equimolar hexane + decane mixture, at 258 K in the range 3.5–12 MPa. The results for the ternary system show that the solubility of methane in the equimolar mixture of alkanes increases when the pressure is increased at constant temperature and it increases as the temperature decreases in the whole pressure range studied. For the quaternary system with a constant amount of nitrogen, the solubility of methane in the liquid phase increases as the pressure increases at the studied temperature. The experimental results for the ternary system were satisfactorily correlated with the Peng–Robinson equation of state in the ranges of pressure and temperature studied. The equation of state was used to predict the behavior of the quaternary system using binary interaction parameters. The applicability of the principle of congruence was corroborated by comparing the vapor–liquid behavior of methane in the equimolar hexane + decane mixture with that in pure octane, at the three temperatures studied in this work.     

Thermodynamics of mixing for binary mixtures of 1-octanol and 1-decanol with n-dodecane and ternary mixture of (TBP + 1-octanol + dodecane) at T = (298.15 to 323.15) K

Densities (ρ) and speed of sound (u) of the binary mixtures of 1-octanol and 1-decanol with dodecane and ternary mixture of {1-octanol + tributyl phosphate (TBP) + dodecane} were measured at temperatures from (298.15 to 323.15) K over the entire composition range and at atmospheric pressure. Using these experimentally determined quantities, the excess molar volume (V^E), excess isentropic compressibility (${\kappa }_{\text{s}}^{\text{E}}$) for the binary mixtures and internal pressure (p_i) of (alcohol + dodecane) binary mixtures have been calculated. The deviations shown by the excess quantities have been interpreted in terms of intermolecular interactions and structure of components. Using Hildebrand regular solution theory, several other parameters like the enthalpy and entropy of mixing of the binary components have been obtained. From acoustic measurements, the probable dimerization constant of the alcohols has also been determined. The values of these parameters give an indication of the subtle structural changes that occur in these binary mixtures.     

Temperature dependence on mutual solubility of binary (methanol + limonene) mixture and (liquid + liquid) equilibria of ternary (methanol + ethanol + limonene) mixture

Mutual solubility data of the binary (methanol + limonene) mixture at the temperatures ranging from 288.15 K close to upper critical solution temperature, and ternary (liquid + liquid) equilibrium (tie-lines) of the (methanol + ethanol + limonene) mixture at the temperatures (288.15, 298.15, and 308.15) K have been obtained. The experimental results have been represented accurately in terms of the extended and modified UNIQUAC models with binary parameters, compared with the UNIQUAC model. The temperature dependence of binary and ternary (liquid + liquid) equilibrium for the binary (methanol + limonene) and ternary (methanol + ethanol + limonene) mixtures could be calculated successfully using the extended and modified UNIQUAC model.