Liquid–(Solid + Liquid) Transitions in a Two-Component System of (CH 3 )CCl 3 + CCl 4

Liquid–(solid + liquid) transitions are studied in (CH3)CCl3 + CCl4 by using the Landau phenomelogical model. The Gibbs energy is expanded in terms of the orientational disorder (OD) parameters for the transitions of the liquid–(rhombohedral + liquid) and liquid–(face-centered cubic + liquid) in a two component system of (CH3)CCl3 + CCl4. From the Gibbs energy, the phase line equations are derived for the transitions studied and they are fitted to the observed T–X phase diagram of (CH3)CCl3 + CCl4 for the concentration (X) CCl4. Temperature and concentration dependences of the OD parameters (Ψ and η) and the inverse susceptibility ($$\chi_{\psi }^{ - 1}$$ and $$\chi_{\eta }^{ - 1}$$) for the two transitions of interest, are predicted by using the melting curves of (CH3)CCl3 + CCl4 on the basis of the Landau phenomenological model. Our predictions, which can be compared with the experimental data, indicate that the first order transition of the liquid–(solid + liquid), in particular, for (CH3)CCl3 + CCl4 can be described satisfactorily by the Landau mean field model.     

Solid–Liquid Phase Equilibria in the Ternary Systems (LiBO 2 + NaBO 2 + H 2 O) and (LiBO 2 + KBO 2 + H 2 O) at 288.15 K and 0.1 MPa

Solid–liquid phase equilibria for the two aqueous systems (LiBO2 + NaBO2 + H2O) and (LiBO2 + KBO2 + H2O) at T = 288.15 K and p = 0.1 MPa were determined using the isothermal dissolution equilibrium method. The experimental results show that the phase diagrams consist of one two-salt co-saturated invariant point, two univariant solubility isotherms, and three crystallization fields. The two systems belong to simple co-saturated type, and neither double salt nor solid solution were found. The densities change regularly as the sodium metaborate (potassium metaborate) concentration increases in solution, and reach their maximum values at the invariant point. Based on the Pitzer and its extended Harvie–Møller–Weare (HMW) model, the solubilities for the ternary systems at 288.15 K were represented, and the calculated results agree well with the experimental values.     

Volumetric and viscometric properties of aqueous solutions of N-(2-hydroxyethyl)morpholine at T = (293.15, 303.15, 313.15, 323.15, 333.15) K

Densities, ρ, and viscosities, η, of aqueous solutions of N-(2-hydroxyethyl)morpholine were measured over the entire composition range at T = (293.15, 303.15, 313.15, 323.15, 333.15) K and at atmospheric pressure. The excess molar volumes V^E and viscosity deviations η^E of aqueous solutions were calculated from the experimental results of density and viscosity measurements and fitted to the Redlich–Kister polynomial equation. Apparent molar volumes V?, partial molar volume at infinite dilution V^∞, and the thermal expansion coefficient α were also calculated. The V^E values were found to be negative over the entire composition range at all temperatures studied and become less negative with increasing temperature, whereas the viscosity data η^E exhibited positive deviations from ideal behaviour.     

Comments on “Physicochemical Properties and Spectral Studies for Binary Systems of 2-Ethoxyethanol (1) + Water (2) and + Dimethyl Sulfoxide (2)”

The activation Gibbs energies, activation enthalpies and activation entropies reported by the authors were found to be internally inconsistent. Errors were also found in the numerical values of the Redlich–Kister equation coefficients for describing the excess molar volumes and viscosity deviations of both binary systems studied by the authors.     

Excess molar volumes and viscosities of (1,1,2,2-tetrabromoethane + 1-alkanols) at T = (293.15 and 303.15) K

Density and viscosity measurements for binary mixtures of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-hexanol, or + 1-heptanol, or + 1-octanol, or + 1-decanol) at T = (293.15 and 303.15) K, have been conducted at atmospheric pressure. The excess molar volumes V^E, have been calculated from the experimental measurements, and the results were fitted to Redlich–Kister equation. The viscosity data were correlated with the model of Grunberg and Nissan, and McAllister four-body model. The excess molar volumes of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-haxanol, or + 1-heptanol, or + 1-octanol) had a sigmoidal shape and the values varied from negative to positive with the increase in the molar fraction of 1,1,2,2-tetrabromoethane. The remaining binary mixture of (1,1,2,2-tetrabromoethane + 1-decanol) was positive over the entire composition range. The effects of the 1-alkanol chain length as well as the temperature on the excess molar volume have been studied. The results have been qualitatively used to explain the molecular interaction between the components of these mixtures.     

Experimental Determination and Correlation of Liquid–Liquid Equilibria Data for the Ternary Systems of Water + 1-Butanol + Solvents (Isophorone and Mesityl Oxide) at Different Temperatures

Liquid–liquid equilibria (LLE) data for {water + 1-butanol + isophorone} and {water + 1-butanol + mesityl oxide} ternary systems were investigated systematically at different temperatures under atmospheric pressure. The Othmer–Tobias and Bachman equations were applied to analyze the dependability of the experimental LLE data. Selectivities and distribution coefficients were used to evaluate the extractive efficiency of the extractants. The Non-Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models were applied to correlate the studied systems and were well represented with all root mean square deviations (RMSD) less than 0.2%. Meanwhile, binary interaction parameters among these compounds were acquired during the correlation process.     

Thermodynamic and physicochemical properties of binary mixtures of nitromethane with {2-methoxyethanol + 2-butoxyethanol} systems at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K

The density, relative permittivity, viscosity and speed of sound at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K in the binary mixtures of nitromethane with 2-methoxyethanol and 2-butoxyethanol have been measured as a function of composition. From the experimental results, the excess molar volumes V^E, excess Gibbs free energy of activation for viscous flow $(\mathrm{\Delta }{G}^{1E})$, excess isentropic compressibility $({\kappa }_s^E)$ and the deviations in the relative permittivity, viscosity, and speed of sound from a mole fraction average have been calculated. The viscosity data, at T = 298.15 K, were correlated with equations of Hind et al., Grunberg and Nissan, Frenkel, and McAllister. The results are discussed in terms of intermolecular interactions and structure of studied binary mixtures.     

Viscosities of binary mixtures of some n-ethoxyethanols with ethyl tert-butyl ether at T = (293.15, 298.15, and 303.15) K

Viscosities at T = (293.15, 298.15, and 303.15) K in the binary mixtures of ethyl tert-butyl ether with 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, and 2-[2-(2-ethoxyethoxy)ethoxy]ethanol have been measured over the entire range of mixture compositions. From the experimental data, deviations in the viscosity (Δln η) and excess energies of activation for viscous flow (ΔG^1E) have been calculated. The viscosity data were correlated with equations of Hind et al., Grunberg and Nissan, Auslaender, and McAllister. The results for Δln η and ΔG^1E are discussed in terms of intermolecular interactions and structure of studied binary mixtures.     

Volumetric properties of binary mixtures of N-ethylformamide with tetrahydrofuran, 2-butanone,and ethylacetate from T = (293.15 to 313.15) K

Densities of binary liquid mixtures of N-ethylformamide (NEF) with tetrahydrofuran (THF), 2-butanone (B), and ethylacetate (EA) were measured at temperatures from (293.15 to 313.15) K and at atmospheric pressure over the whole composition range. Excess molar volumes, V^E, have been obtained from values of the experimental density and were fitted to the Redlich–Kister polynomial equation. The V^E values for all three mixtures are negative over the entire composition and temperature ranges. The V^E values become more negative as the temperature increases for all binary mixtures studied. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes, apparent molar volumes, partial molar excess volumes and excess thermal expansions have been calculated.     

Partition behaviour of benzoic acid in (water + n-dodecane) solutions at T = (293.15 and 298.15) K

The partition coefficients of benzoic acid in solutions of two immiscible solvents, water and n-dodecane, were measured at temperatures of (293.15 and 298.15) K. The experimental results indicated that at both temperatures the partition coefficients were not constant, but showed linear dependences on the concentration of benzoic acid in water. Dimerization of benzoic acid in n-dodecane and ionization in water were assumed based on the chemical theory and the experimental results verified this assumption quite well. Accordingly the association equilibrium constants of benzoic acid in n-dodecane were obtained by a linear regression. The regression results also showed that there was a very strong dimerization of benzoic acid in n-dodecane over the temperatures and concentration range investigated.     

Ultrasound speeds and molar isentropic compressions of (3-ethoxypropane-1-amine + water) mixtures from T = (283.15 to 303.15) K

Alkoxyamines containing two hydrophilic groups with great affinity to water are multipurpose compounds with important applications, either on theoretical or practical grounds. The thermodynamic characterization of aqueous mixtures of these compounds is scant. Ultrasound speed measurements have been made in 53 mixtures of the aqueous ethoxypropane-1-amine binary system, across the entire composition range and temperatures between T = (283.15 and 303.15) K, at atmospheric pressure. By combining ultrasound speed and density data, values of the isentropic compressibility were derived. Excess molar isentropic compressions were estimated and analytically fitted to Redlich–Kister polynomial equations. Excess partial molar quantities were then calculated including their limiting values, which were obtained from the Redlich–Kister fitting coefficients. The temperature dependences of limiting partial molar isentropic compressions and isobaric expansions were also scrutinized. Compressibility changes associated with different patterns of aggregation and hydration over the whole composition range are identified.     

Excess molar volume of (linalool + an alkanol) atT = 303.15 K

In this paper, densities of (linalool  +  methanol, or ethanol, or n -propanol, or n -butanol) are determined at T =  303.15 K using a vibrating-tube densimeter. The excess molar volumes V_m^Evalues are negative in all the systems over the entire composition range and correlated by the Redlich–Kister equation. The effects of chain length of alkanols onV_m^E have been discussed.     

(Liquid + liquid) equilibria for (benzene + cyclohexane + dimethyl sulfoxide) system at T = (298.15 or 303.15) K: Experimental data and correlation

(Liquid + liquid) equilibrium (LLE) data were measured experimentally at T = (298.15 or 303.15) K and atmospheric pressure for the (benzene + cyclohexane + dimethyl sulfone (DMSO)) system. The Othmer–Tobias equation was applied to verify the reliability of the data. Based on the data, the selectivity of DMSO was estimated and compared with that of ionic liquids. The highest selectivity coefficient of DMSO can reach beyond 14, which means it is able to compete with some ionic liquids and it would be a good extractant to separate benzene from cyclohexane. At the same time, the NRTL model was used to correlate the data and the results show that the model agrees on the experimental data very well.     

Influence of temperature on the (liquid + liquid) equilibria of {3-methyl pentane + cyclopentane + methanol} ternary system at T = (293.15, 297.15, and 299.15) K

In order to show the influence of temperature on the (liquid + liquid) equilibria (LLE) of the {3-methyl pentane (1) + cyclopentane (2) + methanol (3)} ternary system, equilibrium results at T = (293.15, 297.15, and 299.15) K are reported. The effect of the temperature on the (liquid + liquid) equilibrium is determined and discussed. Experimental results show that this ternary system is completely homogeneous beyond T = 300 K. All chemicals were quantified by gas chromatography using a thermal conductivity detector. The tie line results were satisfactorily correlated by the Othmer and Tobias method, and the plait point coordinates for the three temperatures were estimated. Experimental values for the ternary system are compared with values calculated by the NRTL and UNIQUAC equations, and predicted by means of the UNIFAC group contribution method. It is found that the UNIQUAC and NRTL models provide similar good correlations of the solubility curve at these three temperatures. Finally, the UNIFAC model predicts binodal band type curves in the range of temperatures studied here, similar to those observed for systems classified by Treybal as type 2, instead of type 1 as experimentally observed. Distribution coefficients were also analysed through distribution curves.     

Viscosity,density, and speed of sound of methylcyclopentane with primary and secondary alcohols at T = (293.15, 298.15, and 303.15) K

Viscosities, densities, and speed of sound have been measured over the whole composition range for (methylcyclopentane with ethanol, 1-propanol, 1-butanol, 2-propanol, 2-butanol, and 2-pentanol) at T = (293.15, 298.15, and 303.15) K and atmospheric pressure along with the properties of the pure components. Excess molar volumes, isentropic compressibility, deviations in isentropic compressibility, and viscosity deviations for the binary systems at the above-mentioned temperatures were calculated and fitted to Redlich–Kister equation to determine the fitting parameters and the root-mean square deviations. UNIQUAC equation was used to correlate the experimental data. Dynamic viscosities of the binary mixtures have been predicted using UNIFAC-VISCO and ASOG-VISCO methods.     

Densities and volumetric properties of (N-(2-hydroxyethyl)morpholine + ethanol, + 1-propanol, + 2-propanol, + 1-butanol,and + 2-butanol) at (293.15, 298.15, 303.15, 313.15, and 323.15) K

Densities of binary mixtures of N-(2-hydroxyethyl)morpholine with ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol were measured over the entire composition range at temperatures from (293.15 to 323.15) K and atmospheric pressure using a vibrating-tube densimeter. The excess molar volumes, V^E were calculated from density data and fitted to the Redlich–Kister polynomial equation. Apparent molar volumes, partial molar volume at infinite dilution and the thermal expansion coefficient of the mixtures were also calculated. The V^E values were found to be negative over the entire composition range and at all temperatures studied and become less negative with increasing carbon chain length of the alkanols.