Densities,excess volumes,isobaric expansivity,and isothermal compressibility of the (1-ethyl-3-methylimidazolium ethylsulfate + methanol) system at temperatures (283.15 to 333.15) K and pressures from (0.1 to 35) MPa

Densities of pure 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid – [C₂mim][EtSO₄] and its mixtures with methanol have been measured with an accuracy of ±0.2 kg · m^?3, over the temperature range (283.15 to 333.15) K and pressure range (0.1 to 35) MPa, using a vibrating tube densimeter. Excess volumes have been calculated directly from the experimental densities. The latter data have been correlated by the Tait equation with the temperature dependent parameters for the pure ionic liquid and by a van Laar-type equation, involving parameters dependent on temperature and pressure for the mixtures. The isobaric expansivity, isothermal compressibility, and related excess properties have been calculated. The exceptionally strong influence of pressure and temperature on these properties has been observed.     

Binary and ternary LLE data of the system (ethylbenzene + styrene + 1-ethyl-3-methylimidazolium thiocyanate) and binary VLE data of the system (styrene + 1-ethyl-3-methylimidazolium thiocyanate)

The distillation of close boiling mixtures may be improved by adding a proper affinity solvent, and thereby creating an extractive distillation process. An example of a close boiling mixture that may be separated by extractive distillation is the mixture ethylbenzene/styrene. The ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) is a promising solvent to separate ethylbenzene and styrene by extractive distillation. In this study, (vapour + liquid) equilibrium data have been measured for the binary system (styrene + [EMIM][SCN]) over the pressure range of (3 to 20) kPa and binary and ternary (liquid + liquid) equilibrium data of the system (ethylbenzene + styrene + [EMIM][SCN]) at temperatures (313.2, 333.2 and 353.2) K. Due to the low solubility of ethylbenzene in [EMIM][SCN], it was not possible to measure accurately VLE data of the binary system (ethylbenzene + [EMIM][SCN]) and of the ternary system (ethylbenzene + styrene + [EMIM][SCN]) using the ebulliometer. Because previous work showed that the LLE selectivity is a good measure for the selectivity in VLE, we determined the selectivity with LLE. The selectivity of [EMIM][SCN] to styrene in LLE measurements ranges from 2.1 at high styrene raffinate purity to 2.6 at high ethylbenzene raffinate purity. The NRTL model can properly describe the experimental results. The rRMSD in temperature, pressure and mole fraction for the binary VLE data are respectively (0.1, 0.12 and 0.13)%. The rRMSD is only 0.7% in mole fraction for the LLE data.     

Thermodynamic description of liquid–liquid equilibria in systems 1-ethyl-3-methylimidazolium ethylsulfate + C7-hydrocarbons by polymer-solution models

In the present paper, liquid–liquid equilibrium in binary systems containing the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate is studied. It was suggested in papers published by other authors that 1-ethyl-3-methylimidazolium ethylsulfate could potentially be a suitable solvent for extracting aromatic compounds from mixtures containing aliphatic hydrocarbons, such as naphtha cracker feeds. To be able to assess the selectivity of 1-ethyl-3-methylimidazolium ethylsulfate towards aliphatic, cyclic, and aromatic hydrocarbons, mutual solubilities of the ionic liquid and n-heptane, methylcyclohexane, and toluene were measured by the volumetric method. To evaluate quantitatively the quality of the experimental data and their agreement with available literature values, a correlation by two polymer-solution models, the modified Flory–Huggins equation proposed by De Sousa and Rebelo and the thermodynamic lattice model proposed by Qin and Prausnitz was carried out, the model parameters being optimized by a gnostic regression method.     

Densities and dynamic viscosities of the binary system (water + 1-hexyl-3-methylimidazolium bromide) at different temperatures

Densities and viscosities were measured for pure ionic liquid [C₆mim][Br] (1-hexyl-3-methylimidazolium bromide) and the binary system (water + [C₆mim][Br]) at 0.1 MPa and in the (293.15 to 333.15) K range. The excess molar volume and viscosity deviation were calculated and correlated by Redlich–Kister polynomial expansions. The fitting parameters and the standard deviations were determined.     

Compressed liquid densities and excess molar volumes for (CO2 + 1-pentanol) binary system at temperatures from 313 to 363 K and pressures up to 25 MPa

Measurements of compressed liquid densities for 1-pentanol and for {CO₂ (1) + 1-pentanol (2)} system were carried out at temperatures from 313 K to 363 K and pressures up to 25 MPa. Densities were measured for binary mixtures at 10 different compositions, x₁ = 0.0816, 0.1347, 0.3624, 0.4651, 0.6054, 0.7274, 0.8067, 0.8573, 0.9216, and 0.9757. A vibrating tube densimeter was used to perform density measurements using two reference calibration fluids. The uncertainty is estimated to be better than ±0.2 kg · m^?3 for the experimental density measurements. For each mixture and for 1-pentanol, the experimental densities were correlated using an explicit volume equation of six parameters and an 11-parameter equation of state (EoS). Excess molar volumes were determined for the (CO₂ + 1-pentanol) system using 1-pentanol densities calculated from the 11-parameter EoS and CO₂ densities calculated from a multiparameter reference EoS.     

(Liquid + liquid) equilibria in the binary systems (aliphatic,or aromatic hydrocarbons + 1-ethyl-3-methylimidazolium ethylsulfate,or 1-butyl-3-methylimidazolium methylsulfate ionic liquids)

(Liquid + liquid) equilibria of 14 binary systems composed of n-hexane, n-heptane, benzene, toluene, o-xylene, m-xylene, or p-xylene and 1-ethyl-3-methylimidazolium ethylsulfate, [emim]EtSO₄, or 1-butyl-3-methylimidazolium methylsulfate, [bmim]MeSO₄, ionic liquids have been done in the temperature range from (293.2 to 333.2) K. The solubility of aliphatic is less than those of the aromatic hydrocarbons. In particular, the solubility of hydrocarbons in both ionic liquids increases with the temperature in the order n-heptane < n-hexane < m-xylene < p-xylene < o-xylene < toluene < benzene. Considering the high solubility of aromatics and the low solubility of aliphatic hydrocarbons as well as totally immiscibility of the ionic liquids in all hydrocarbons, these new green solvents may be used as potentials extracting solvents for the separation of aromatic and aliphatic hydrocarbons.     

Binary and ternary (liquid + liquid) equilibrium for {methylcyclohexane (1) + toluene (2) + 1-hexyl-3-methylimidazolium tetracyanoborate (3)/1-butyl-3-methylimidazolium tetracyanoborate (3)}

This paper focuses on the study of the solubility behaviour of 1-hexyl-3-methylimidazolium tetracyanoborate [HMIM][TCB] and 1-butyl-3-methylimidazolium tetracyanoborate [BMIM][TCB] in combination with methylcyclohexane and toluene as representatives for non-aromatic and aromatic components. Binary and ternary (liquid + liquid) equilibrium data were collected at three different temperatures and at atmospheric pressure (0.1 MPa). The experimental data were well-correlated with the NRTL and UNIQUAC thermodynamic models; however, the UNIQUAC model gave better predictions than the NRTL, with a root mean square error below 0.97%. The non-aromatic/aromatic selectivities of the ionic liquids make them suitable solvents to be used in extractive distillation processes.     

Measurements of densities,viscosities, speeds of sound and relative permittivities and excess molar volumes,excess isentropic compressibilities and deviations in relative permittivities and molar polarizations for dibutyl ether + benzene, + toluene and + p-xylene at different temperatures

The densities ρ, dynamic viscosities η, speeds of sound u, and relative permittivities ε_r, for (dibutyl ether + benzene, or toluene, or p-xylene) have been measured at different temperatures over the whole composition range and at atmospheric pressure. The mixture viscosities have been correlated with semi empirical equations. Calculations of the speed of sound based on Nomoto’s equation have been found to be close to experimental values for the three mixtures and at two temperatures. Excess functions such as excess molar volumes V_m^E, excess isentropic compressibilities κ_s^E, deviations in relative permittivities δε_r, and molar polarizations δP_m were calculated and fitted to Redlich–Kister type equations.     

The excess molar enthalpies and volumes of (N-methyl-2-pyrrolidinone + an alkan-1-ol) at T=298.15 K

The excess molar enthalpies H_m^E, for the mixtures (N-methyl-2-pyrrolidinone + ethanol, or pentan-1-ol, or hexan-1-ol, or heptan-1-ol, or octan-1-ol, or nonal-1-ol, or decan-1-ol, or undecan-1-ol) at T=298.15 K and atmospheric pressure have been obtained using flow calorimetry. Excess molar volumes at T=298.15 K and atmospheric pressure have also been determined for (N-methyl-2-pyrrolidinone + nonal-1-ol, or decan-1-ol, or undecan-1-ol) from density measurements using a vibrating tube densimeter. The experimental results have been correlated and compared with the results from the Flory–Benson–Treszczanowicz (FBT) theory and from the Extended Real Associated Solution (ERAS) model. The ERAS model accounts free volume effects according to the Flory–Patterson model and additionally association effects between the molecules involved. For the mixtures studied here the association effects arise from the self association of an alkan-1-ol molecules and also the cross-association of the proton of the alkan-1-ol with carbonyl oxygen of N-methyl-2-pyrrolidinone (NMP) molecule. The parameters adjusted to the mixtures properties are two cross-association parameters and the interaction parameter responsible for the exchange energy of the van der Waals interactions. Self-association parameters of the alcohols and NMP are taken from the literature.     

Excess molar volumes,and excess molar enthalpies of (N-methyl-2-pyrrolidinone + an ether ) at the temperature 298.15 K

Excess molar volumes V_m^E have been calculated from measured density values over the whole composition range at T =  298.15 K and atmospheric pressure for six { N -methyl-2-pyrrolidinone  +  1,1-dimethylethyl methyl ether, or dipropyl ether, or 1,1-dimethylpropyl methyl ether, or diisopropyl ether, or dibutyl ether, or dipentyl ether}. Excess molar enthalpiesH_m^E were also measured for five { N -methyl-2-pyrrolidinone  +  1,1-dimethylethyl methyl ether, or dipropyl ether, or 1,1-dimethylpropyl methyl ether, or diisopropyl ether, or dibutyl ether} at T =  298.15 K and atmospheric pressure. The results are discussed in terms of intermolecular associations. The experimental results have been correlated with the UNIQUAC and NRTL equations.     

Physical properties of the ternary system (ethanol + water + 1-butyl-3-methylimidazolium methylsulphate) and its binary mixtures at several temperatures

In this paper, we report experimental densities, dynamic viscosities, and refractive indices and their derived properties of the ternary system (1-butyl-3-methylimidazolium methylsulphate + ethanol + water) at T = 298.15 K and of its binary systems 1-butyl-3-methylimidazolium methylsulphate with ethanol and with water at several temperatures T = (298.15, 313.15, 328.15) K. These physical properties have been measured over the whole composition range and at 0.1 MPa. Excess molar volumes, viscosity deviations, and excess free energy of activation for the binary systems at the abovementioned temperatures, were calculated and fitted to the Redlich–Kister equation to determine the fitting parameters and the root-mean-square deviations and for the ternary systems were calculated and fitted to Cibulka, Singh et al., and Nagata and Sakura equations. The ternary excess properties were predicted from binary contributions using geometrical solution models. Refractive indices were measured from T = 298.15 K over the whole composition range for the binary and ternary systems. The results were used to calculate deviations in the refractive index.     

(Liquid + liquid) equilibrium of (NaNO3 + PEG 4000 + H2O) ternary system at different temperatures

Phase diagram and (liquid + liquid) equilibrium (LLE) data for the (NaNO₃ + polyethylene glycol 4000 (PEG 4000) + H₂O) system have been determined experimentally at T = (288.15 and 308.15) K. The effects of temperature on the binodal curves and tie-lines have been studied and it was found that an increasing in temperature caused the expansion of two-phase region. The Chen-NRTL, modified Wilson and UNIQUAC models were used to correlate the experimental tie-line data. The results show that the quality of fitting is better with the UNIQUAC model.     

Excess molar enthalpies and excess molar volumes of (1,3-dimethyl-2-imidazolidinone + an aromatic hydrocarbon) atT = 298.15 K

Excess molar enthalpies H_m^Eand excess molar volumesV_m^E of (1,3-dimethyl-2-imidazolidinone  +  benzene, or methylbenzene, or 1,2-dimethylbenzene, or 1,3-dimethylbenzene, or 1,4-dimethylbenzene, or 1,3,5-trimethylbenzene, or ethylbenzene) over the whole range of compositions have been measured at T =  298.15 K. The excess molar enthalpy values were positive for five of the seven systems studied and the excess molar volume values were negative for six of the seven systems studied. The excess enthalpy ranged from a maximum of 435 J · mol ^− 1for (1,3-dimethyl-2-imidazoline  +  1,3,5-trimethylbenzene) to a minimum of  − 308 J · mol ^− 1for (1,3-dimethyl-2-imidazoline  +  benzene). The excess molar volume values ranged from a maximum of 0.95cm³mol ^− 1 for (1,3-dimethyl-2-imidazoline  +  ethylbenzene) and a minimum of  − 1.41 cm³mol ^− 1for (1,3-dimethyl-2-imidazoline  +  methylbenzene). The Redlich–Kister polynomial was used to correlate both the excess molar enthalpy and the excess molar volume data and the NRTL and UNIQUAC models were used to correlate the enthalpy of mixing data. The NRTL equation was found to be more suitable than the UNIQUAC equation for these systems. The results are discussed in terms of the polarizability of the aromatic compound and the effect of methyl substituents on the benzene ring.     

Excess enthalpies and excess volumes of (2-methoxyethanol + 1,4-dioxane) and (1,2-dimethoxyethane + benzene) at temperatures between 283.15 K and 313.15 K

The measurement of excess enthalpies, H^E, at T=298.15 K and densities at temperatures between 283.15 K and 313.15 K are reported for the (2-methoxyethanol + 1,4-dioxane) and (1,2-dimethoxyethane + benzene) systems. The values of H^E and the excess volumes, V^E, are positive, and the temperature dependence of V^E is quite small for (2-methoxyethanol + 1,4-dioxane). The (1,2-dimethoxyethane + benzene) system shows a negative H^E and sigmoid curves in V^E, which change sign from positive to negative with an increase in 1,2-dimethoxyethane. The temperature dependence of V^E for this system is negative.     

Excess molar volumes and excess molar enthalpies of binary mixtures for 1,2-dichloropropane + 2-alkoxyethanol acetates at 298.15 K

The excess molar volumes and excess molar enthalpies over the whole range of composition have been measured for the binary mixtures formed by 1,2-dichloropropane (1,2-DCP) with three 2-alkoxyethanol acetates at 298.15 K and atmospheric pressure using a digital vibrating-tube densimeter and an isothermal calorimeter with flow-mixing cell, respectively. The 2-alkoxyethanol acetates are ethylene glycol monomethyl ether acetate (EGMEA), ethylene glycol monoethyl ether acetate (EGEEA), and ethylene glycol monobutyl ether acetate (EGBEA). The of the mixture has been shown positive for EGMEA, ‘S-shaped’ for EGEEA, being negative at low and positive at high mole fraction of 1,2-DCP, and negative for EGBEA. All the values for the above mixtures showed an exothermic effect (negative values) which increase with increase in carbon number of the 2-alkoxyethanol acetates, showing minimum values varying from −374 J mol⁻¹ (EGMEA) to −428 J mol⁻¹ (EGBEA) around 0.54–0.56 mol fraction of 1,2-DCP. The experimental results of and were fitted to Redlich–Kister equation to correlate the composition dependence of both excess properties. In this work, the experimental excess enthalpy data have been also correlated using thermodynamic models (Wilson, NRTL, and UNIQUAC) and have been qualitatively discussed.     

Temperature dependence of the excess molar volume of (heptane + 1-chloroalkane)

The densities of (heptane + 1-chlorobutane, or 1-chloropentane, or 1-chlorohexane) were measured at the temperatures (308.15, 318.15, and 328.15) K by means of a vibrating-tube densimeter. The excess molar volumes, V_m^E, calculated from the density data, along with our previous data⁽¹⁾ determined at T=298.15 K for the same systems, provide the temperature dependence of V_m^E in the temperature range of 298 to 328 K. The V_m^E results were correlated using the fourth-order Redlich–Kister equation, with the maximum likelihood principle applied for the determination of the adjustable parameters. It was found that the deviations from ideal behaviour (both positive and negative) in the systems studied increase with increasing temperature.     

(Liquid + liquid) equilibria of (water + propionic acid + 2-ethyl-1-hexanol): Experimental data and correlation

(Liquid + liquid) equilibrium (LLE) data for (water + propionic acid + 2-ethyl-1-hexanol) were determined at atmospheric pressure over the temperature range of (298.15 to 308.15) K. A type-1 LLE phase diagram was obtained for this ternary system. The LLE data were correlated fairly well with UNIQUAC model, indicating the reliability of the UNIQUAC equation for this ternary system. The average root mean square deviation between the observed and calculated mole fractions was 1.57%. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvent.