Excess molar enthalpies for ternary mixtures of (methanol or ethanol + water + tributyl phosphate) at <Emphasis Type="Italic">T</Emphasis> = 298.15 K

Excess molar enthalpies for two ternary mixtures of {x ₁ tributylphosphate (TBP) + x ₂ water + x ₃ methanol/ethanol} were measured at T = 298.15 K and atmospheric pressure using a TAM Air isothermal calorimeter, by mixing methanol or ethanol with binary mixtures of (water + TBP). Excess enthalpies for initial binary mixtures of (water + TBP) were also measured under the same conditions, which showed phase separation at low molar fraction of TBP. Experimental results of the ternary mixtures were expressed with constant excess molar enthalpy contours on Roozeboon diagrams.     

Excess enthalpies of binary mixtures of <Emphasis Type="Italic">ortho</Emphasis>-, <Emphasis Type="Italic">meta</Emphasis>-, <Emphasis Type="Italic">para</Emphasis>-structural isomers containing aliphatic group

To obtain further systematic information for the isomer systems, the excess molar enthalpies for binary (o + m), (o + p), (m + p)-isomers of methoxymethylbenzene, ethylmethylbenzene, diethylbenzene, chloromethylbenzene, tolunitrile and fluorobenzonitrile, tolylacetonitrile were measured at 298.15 K. In this article, the results are discussed and compared with those of previous works. The excess enthalpies of binary systems in different solid and liquid states were measured when the pure component of o-/m-tolunitrile, fluorobenzonitrile was titrated into the prior (o + p) or (m + p) mixtures. A series calculation for the interaction energies (IE) between the isomers was carried out for the pair molecules by ab initio MO of Gaussian 09. Correlations between the excess enthalpies at a molar fraction of x = 0.5 and the intermolecular energy are discussed.     

Excess molar properties of ternary system (ethanol + water + 1,3-dimethylimidazolium methylsulphate) and its binary mixtures at several temperatures

The density, dynamic viscosity, and refractive index of the ternary system (ethanol + water + 1,3-dimethylimidazolium methylsulphate) at T = 298.15 K and of its binary systems 1,3-dimethylimidazolium methylsulphate with ethanol and with water at several temperatures T = (298.15, 313.15, and 328.15) K and at 0.1 MPa have been measured over the whole composition range. From these physical properties, excess molar volumes, viscosity deviations, refractive index deviations, and excess free energy of activation for the binary systems at the above mentioned temperatures, were calculated and fitted to the Redlich–Kister equation to determine the fitting parameters and the root-mean-square deviations. For the ternary system, the excess properties 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.     

Thermodynamic properties of new heat pump working pairs: 1,3-Dimethylimidazolium dimethylphosphate and water,ethanol and methanol

Ionic liquid 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]) + water/ethanol/methanol mixtures exhibit properties which render them suitable as candidates for working pairs in industrial applications of absorption heat pumps or chillers. In this paper, the thermodynamic properties including vapor pressure, density, viscosity, heat capacity as well as excess enthalpy of these binary systems were measured at various temperatures with different ionic liquid concentrations. The thermodynamic properties were correlated by different equations, respectively. The correlated values were significantly consistent with the experimental ones. In conclusion, the vapor–liquid equilibrium (VLE) data indicated that the vapor pressures of the three solvents in [MMIM][DMP] displayed a considerable negative deviation from Raoult's law, and the excess enthalpies of the three binary systems are negative. These characteristics are necessary and important for an absorption working pair.     

Excess enthalpies of ether + alcohol + hydrocarbon mixtures: Binary and ternary mixtures containing dibutyl ether (DBE), 1-butanol and benzene at 298.15 K and 313.15 K

Experimental excess molar enthalpies of the ternary systems dibutyl ether (DBE) + 1-butanol + benzene and the corresponding binary systems at T = 298.15 K and T = 313.15 K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and the ternary systems show endothermic character. The experimental data for the binary and ternary systems have been fitted using the Redlich-Kister equation and the NRTL and UNIQUAC models. The values of the standard deviation indicate good agreement between the experimental results and those calculated from the equations.     

(Vapor + liquid) equilibria for the {water + poly(ethylene glycol diacetyl ether) (PEGDAE) and methanol + PEGDAE} systems

We measured binary (vapor + liquid) equilibrium data for the {water + poly(ethylene glycol diacetyl ether) (PEGDAE) and methanol + PEGDAE} systems at pressures up to 400 kPa and temperatures from 333 K to 393 K. A static apparatus was used in this study. The measured data were correlated by the Peng–Robinson equation of state using the Wong–Sandler mixing rules with NRTL as the excess Gibbs free energy model.     

Experimental and predicted excess molar enthalpies for 1,4-dioxane + octane + cyclohexane at 303.15 K

Excess molar enthalpies for the ternary system 1,4-dioxane (1) + n-octane (2) + cyclohexane (3) and for the three constituent binary systems have been measured by a Calvet microcalorimeter at 303.15 K and ambient pressure. The experimental binary results were fitted by the Redlich–Kister equation. The excess molar enthalpies of the ternary system were correlated using the Cibulka equation. The DISQUAC group contribution model was applied to predict the excess molar enthalpy for this mixture.     

Complex Formation of Crown Ethers and Cations in Water–Organic Solvent Mixtures: Part XII. Effect of the Acid–Base Properties of the Mixture on the Thermodynamic Functions of Complex Formation of Benzo-15-Crown-5 with Na<Superscript>+</Superscript> in Water–Methanol Mixtures at 298.15 K

The enthalpies of solution of benzo-15-crown-5 ether in methanol–water mixtures and methanol–water–sodium iodide systems have been measured at 298.15 K. The values of standard enthalpies of solution of benzo-15-crown-5 ether are positive in the mixtures of water and methanol within the whole range of mixture composition. The equilibrium constants of complex formation of benzo-15-crown-5 ether with the sodium cation have been determined by conductivity measurements at 298.15 K. The thermodynamic functions of the formation of these complexes have been calculated. The Gibbs energy of complex formation depends on the base–acid properties of methanol–water mixture.     

Vapor pressures,excess enthalpies,and specific heat capacities of the binary working pairs containing the ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate

In present research the binary solutions containing ionic liquid (IL), 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM] [DMP]), are considered as new working pairs for absorption heat pumps or absorption refrigerators. The IL was synthesized in the lab and mixed with water, ethanol, or methanol. Experimental (vapor + liquid) equilibrium (VLE) of these binary systems was measured at different mole fractions ranging from 0.1 to 0.5 and was correlated by the NRTL equation within the average relative deviation of 2%, which means that the (vapor + liquid) equilibrium of these binary solutions containing ionic liquid can be predicted by traditional non-electrolyte solution model. Meanwhile these binary solutions are a negative deviation from Raoult’s law. Excess enthalpy of these binary systems was measured at the temperature of T = 298.15 K and at the pressure of 1 atm. The results indicate that the mixing processes of [EMIM] [DMP] with water, ethanol, or methanol are exothermal, which is a very important characteristic for working pairs used in absorption heat pumps or in absorption refrigerators.     

Enthalpies of solution of l-threonine in a (water + alcohol) mixture at 298.15 K

The enthalpies of solution of l-threonine in the (water + methanol), (water + ethanol), (water + n-propanol), and (water + i-propanol) mixtures, with an alcohol content up to 0.4 mol fractions, have been measured calorimetrically at T = 298.15 K. The standard enthalpies of solution and transfer of l-threonine from water to an aqueous alcohol have been calculated. The effect of the structure properties of the mixed solvent on the specified enthalpy characteristics of l-threonine is discussed. The enthalpy coefficients of pairwise interactions between amino acid and alcohol molecules have been computed. It has been found that these coefficients become increasingly positive in the methanol, ethanol, n-propanol, and i-propanol consequence. A comparative analysis of the thermodynamic characteristics of dissolution of l-threonine and some other amino acids (glycine, l-alanine and l-valine) in the mixtures studied has been made.     

Isothermal vapor–liquid equilibrium at 333.15 K and excess molar volumes at 298.15 K for the ternary system di-isopropyl ether + n-propyl alcohol + toluene and its binary subsystems

Isothermal vapor–liquid equilibrium data at 333.15 K are reported for the ternary system di-isopropyl ether (DIPE) + n-propyl alcohol + toluene and the binary subsystems DIPE + n-propyl alcohol, DIPE + toluene and n-propyl alcohol + toluene by using headspace gas chromatography. The excess molar volumes at 298.15 K for the same binary and ternary systems were also determined by directly measured densities. The experimental binary and ternary vapor–liquid equilibrium data were correlated with different G^E models and the excess molar volumes were correlated with the Redlich–Kister equation for the binary systems and the Cibulka equation for the ternary system, respectively.     

Quaternary Liquid–Liquid Equilibria for Fuel Additive Systems Containing Diethyl Carbonate or 1,1-Dimethylethyl Methyl Ether at 298.15 K and Atmospheric Pressure

Liquid–liquid equilibrium tie line data were determined for three quaternary systems water + ethanol + diethyl carbonate+n-heptane, water + ethanol + 1,1-dimethylethyl methyl ether + diethyl carbonate, and water + 1,1-dimethylethyl methyl ether + diethyl carbonate+n-heptane at 298.15 K and atmospheric pressure. The experimental liquid–liquid equilibria results have been correlated using a modified UNIQUAC model and an extended UNIQUAC model, both with multicomponent interaction parameters in addition to the binary ones.     

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.     

Excess molar enthalpies of the binary systems: (Dibutyl ether + isomers of pentanol) at T = (298.15 and 308.15) K

In this work, we present the experimental measurements of excess molar enthalpies for the binary systems of dibutyl ether with different isomers of pentanol: 1-pentanol, 2-pentanol, 3-pentanol, 3-methyl-2-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-methyl-2-butanol; all of them at T = (298.15 and 308.15) K and atmospheric pressure. Our goal was to determine the influence of the OH-group position on the different isomers of pentanol in the excess molar enthalpies of the binary systems studied. For this purpose we have analysed their experimental effective-reduced dipole moments. All values of excess molar enthalpies for the mixtures studied are positive whereas the results obtained for the effective-reduced dipole moments of the isomers of pentanol are similar.     

Phase equilibrium properties of binary and ternary systems containing di-isopropyl ether + 1-butanol + benzene at 313.15 K

(Vapour + liquid) equilibria data of (di-isopropyl ether + 1-butanol + benzene), (di-isopropyl ether + 1-butanol) and (1-butanol + benzene) have been measured at T = 313.15 K using an isothermal total pressure cell. Data reduction by Barker’s method provides correlations for the excess molar Gibbs energy using the Margules equation for the binary systems and the Wohl expansion for the ternary. The Wilson, NRTL and UNIQUAC models have been applied successfully to both the binary and the ternary systems reported here.     

Isothermal vapor–liquid equilibria for binary mixtures of benzene, toluene, m-xylene, and N-methylformamide at 333.15 K and 353.15 K

Isothermal vapor–liquid equilibrium (VLE) at 333.15 K and 353.15 K for four binary mixtures of benzene + toluene, benzene + N-methylformamide, toluene + m-xylene and toluene + N-methylformamide have been obtained at pressures ranged from 0 kPa to 101.3 kPa. The NRTL, UNIQUAC and Wilson activity coefficient models have been employed to correlate experimental pressures and liquid mole fractions. The non-ideal behavior of the vapor phase has been considered by using the Soave–Redlich–Kwong equation of state in calculating the vapor mole fraction. Liquid and vapor densities were also measured by using two vibrating tube densitometers. The P–x–y diagram and the activity coefficient indicate that two mixtures of benzene + toluene and toluene + m-xylene were close to the ideal solution. However, two mixtures containing N-methylformamide present a large positive deviation from the ideal solution. The excess Gibbs energy in the benzene + toluene mixture is negative indicates that it is an exothermic system.     

Excess enthalpy and excess volume for binary systems of two ionic liquids + water

In this work we report the experimental measurements of excess molar enthalpy and excess molar volume, at 298.15 K and atmospheric pressure, on ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) + water mixtures. Positive enthalpies were found for the two systems (maximum, at x ₁ around 0.37 correspond to about 700 and 900 J mol⁻¹ for EAN and PAN respectively). As the hydrophobic/hydrophilic ratio increases, along with the length of the alkyl chain in the ionic liquids, ILs, the specific interactions IL-water become less important. The excess molar volumes, V ^E, are negative over the entire composition range for the two binary mixtures. They have similar values but curves exhibit a different asymmetric shape and around equimolar composition they intersect each other. This behaviour: positive H ^E and negative V ^E, is not very common.     

Compressibility of ethylene glycol-dimethyl sulfoxide mixtures over the pressure range 0.1–100 MPa at 308.15 K

Compressibility coefficients k were measured for binary ethylene glycol (EG)-dimethyl sulfoxide (DMSO) mixtures over the whole composition range at pressures of 0.1–100 MPa and temperature 308.15 K. Excess molar volumes of mixtures, partial molar volumes of EG and DMSO, and changes in the excess molar Gibbs energy were calculated. The concentration dependences of compressibility factors k passed a minimum at pressures of ∼10 MPa. The k coefficient increased as the pressure grew, and the dependence became linear. The composition dependences of the specific volumes of mixtures passed minima at x ∼ 0.5 as the pressure increased (x is the mole fraction of dimethyl sulfoxide). The excess molar volumes were negative (EG-DMSO mixtures formed with compression). Changes in the excess molar Gibbs energy characterized the stabilizing action of pressure on the EG-DMSO system.     

Knudsen effusion mass spectrometric determination of mixing thermodynamic data of liquid Ag–In–Sn alloy

The vaporisation of a liquid Ag–In–Sn system has been investigated at 1273–1473 K by Knudsen effusion mass spectrometry (KEMS) and the data fitted to a Redlich–Kister–Muggianu (RKM) sub-regular solution model. Nineteen different compositions have been examined at six fixed indium mole fractions, X_In = 0.10, 0.117, 0.20, 0.30, 0.40 and 0.50. The ternary L-parameters, the thermodynamic activities and the thermodynamic properties of mixing have been evaluated using standard KEMS procedures and from the measured ion intensity ratios of Ag⁺ to In⁺ and Ag⁺ to Sn⁺, using a mathematical regression technique described by us for the first time. The intermediate data obtained directly from the regression technique are the RKM ternary L-parameters. From the obtained ternary L-parameters the integral molar excess Gibbs free energy, the excess chemical potentials, the activity coefficients and the activities have been evaluated. Using the temperature dependence of the activities, the integral and partial molar excess enthalpies and entropies were determined. In addition, for comparison, for some compositions, also the Knudsen effusion isothermal evaporation method (IEM) and the Gibbs–Duhem ion intensity ratio method (GD-IIR) were used to determine activities and good agreement was obtained with the data obtained from fitting to the RKM model.     

Excess enthalpies of binary and ternary mixtures containing dibutyl ether (DBE), 1-butanol,and heptane at T = 298.15 K and 313.15 K

Experimental excess molar enthalpies of the ternary systems {dibutyl ether (DBE) + 1-butanol + heptane} and the corresponding binary systems at T = 298.15 K and T = 313.15 K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and the ternary systems show endothermic character. The experimental data for the binary and ternary systems have been fitted using the Redlich–Kister equation, the NRTL and UNIQUAC models. The values of the standard deviation indicate good agreement between the experimental results and those calculated from the equations.