Physico-chemical properties of binary mixtures of 1-butanol with chloroethanes or chloroethenes at 298.15 K

The densities ρ, speeds of sound u, and viscosities η, of pure 1-butanol, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, and tetrachloroethylene and those of their binary mixtures have been measured at 298.15 K and atmospheric pressure over the entire range of compositions. Excess molar volumes V ^E, viscosity deviations Δη, deviation in compressibilities Δκ_s and excess Gibbs energy of activation G*^E, were obtained from the experimental results and those were fitted to Redlich–Kister's type function in terms of mole fractions. Viscosities, speeds of sound and isentropic compressibilities of the binary mixtures have been correlated by means of several empirical and semi-empirical equations. The experimental data are analysed to discuss the nature and strength of intermolecular interactions in these mixtures.     

Densities and speeds of sound for binary mixtures of (1,3-dioxolane or 1,4-dioxane) with (2-methyl-1-propanol or 2-methyl-2-propanol) at the temperatures (298.15 and 313.15) K

This paper reports densities and speeds of sound for the binary mixtures of (1,3-dioxolane or 1,4-dioxane) with (2-methyl-1-propanol or 2-methyl-2-propanol) at the temperatures (298.15 and 313.15) K. Excess volumes and excess isentropic compressibility coefficients have been calculated from experimental data and fitted by means of a Redlich-Kister type equation. The ERAS model has been used to calculate the excess volumes of the four systems at both temperatures.     

Excess heat capacities at T=298.15 K and excess enthalpies at T=293.15 and 298.15 K of aqueous solution of 2-methoxyethanol

Excess isobaric heat capacities of mixture (2-methoxyethanol+water) were measured at T=298.15 K and excess enthalpies at T=293.15 and 298.15 K. Excess enthalpies were extremely exothermic, up to -1290 J mol^-1 atT=293.15 K and -1240 J mol^-1 at T=298.15 K. Excess isobaric heat capacities were positive and very large, approximately 9 J K^-1 mol^-1 at the maximum. In contrast to the data reported by Page and coworkers, the excess heat capacity data were positive in the entire composition range and there was no change in their signs. Consistently, no crossing was found between the curves of excess enthalpies at T=298.15 and 293.15 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Excess molar volume and isentropic compressibility of monoethanolamine in aqueous system at temperatures from 298.15 to 318.15 K

Densities and sound velocities for aqueous monoethanolamine (MEA) system are reported over the entire composition range at different temperatures (298.15, 303.15, 313.15 and 318.15 K). These experimental data have been further used in calculating the excess molar volume, partial molar volumes, isobaric thermal expansion coefficients and the deviation in isentropic compressibility. The excess molar volumes data were fitted to the Redlich–Kister polynomial equation to obtain their coefficients and standard deviations. The partial molar volume at infinite dilution of both water in MEA and MEA in water and have been determined using two different methods. Knowledge of the above properties of these mixtures is a basis for understanding some of the molecular interactions in these systems. From the analysis of the results, the type of interactions between the MEA and water is discussed in terms of the number and size of the alkyl groups attached to the nitrogen atom of MEA.     

Excess enthalpies of water+1,4-dioxane at 278.15, 298.15, 318.15 and 338.15 K

The excess molar enthalpies of (1–x)water+x1,4-dioxane have been measured at four different temperatures. All the mixtures showed negative enthalpies in the range of low mole fraction but positive ones in the range of high mole fraction of 1,4-dioxane. Excess enthalpies were increased with increasing temperature except those of at 278.15 K. Partial molar enthalpies have maximum around x=0.13 and minimum around x=0.75. Three different behaviors for the concentration dependence of partial molar enthalpies were observed for all temperature. Theoretical calculations of molecular interactions of three characteristic concentrations were carried out using the molecular orbital method.     

Binary mixtures of cyclohexanone, 2-butanone, 1,4-dioxane and 1,2-dimethoxyethane

Densities and sound velocities of binary mixtures of cyclohexanone, 2-butanone, 1,4-dioxane and 1,2-dimethoxyethane were measured at 298.15 K and also the densities at 303.15 K. Excess volumes were determined from densities. Isentropic compressibilities were determined from densities and sound velocities, and excess thermal expansion factors were determined from excess volumes of two temperatures. Excess isothermal compressibilities and excess isochoric heat capacities were then estimated using excess isobaric heat capacities previously reported. Excess volumes and excess isentropic and isothermal compressibilities were negative except for cyclohexanone+1,4-dioxane system. This revised version was published online in August 2006 with corrections to the Cover Date.     

Acoustical and excess thermodynamic studies of mixtures of 2-pyrrolidone with 1,3-propanediol and water as well as 1,3-propanediol with water at 308.15 K

The density (ρ), viscosity (η) and ultrasonic velocity (u) of three mixtures consisting of 2- pyrrolidone with 1,3-propanediol (PD) and water and also of PD and water have been measured as a function of mole fraction at 308.15 K. The experimentally collected data has been used to calculate the excess molar volume (V^E), deviation in viscosity (Δη), deviation in ultrasonic velocity (Δu), isentropic compressibility (κ_s), deviation in isentropic compressibility (Δκ_s) and excess Gibbs free energy of activation (ΔG*^E). The Redlich–Kister polynomial equation has been used to fit the derived parameters. The variation in excessive thermodynamic properties as a consequence of possible molecular interactions is discussed.     

Volumetric,viscometric and acoustic properties of binary mixtures of 2-propanol with n -alkanes (C6, C8, C10) at 298.15 and 308.15 K

Densities (ρ), viscosities (η), and speeds of sound, (u) of the binary mixtures of 2-propanol with n-alkanes (n-hexane, n-octane, and n-decane) were measured over the entire composition range at 298.15 and 308.15 K and at atmospheric pressure. Using the experimental values of density, viscosity and speed of sound, the excess molar volumes (V ^E), viscosity deviations (Δη), deviations in speed of sound (Δu), isentropic compressibility (κ _s), deviations in isentropic compressibility (Δκ _s), and excess Gibbs energies of activation of viscous flow (ΔG* ^E) were calculated. These results were fitted to the Redlich–Kister type polynomial equation. The variations of these excess parameters with composition were discussed from the viewpoint of intermolecular interactions in these mixtures. The excess properties are found to be either positive or negative depending on the molecular interactions and the nature of liquid mixtures.     

Thermodynamic Properties of Binary Mixtures of Cyclohexanone with n-Alkanols (C1–C5) at 293.15 K

The excess molar volumes (V^E), excess surface tensions (σ^E), and deviations in molar refraction (R^E) and isentropic compressibility (k_s^E) of binary mixtures of cyclohexanone with methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol have been determined over the entire composition range at 293.15 K. The results were fitted by the Redlich–Kister polynomial equation and the corresponding binary coefficients A_k have been derived. The standard deviations between the calculated and the experimental excess properties have been determined. The results provide information on the interactions of the molecules in the pure liquids as well as in the binary mixtures.     

Thermophysical properties of 1-hexanol over the temperature range from 303 K to 503 K and at pressures from the saturation line to 400 MPa

Isobaric thermal expansivities, _P(T,p), of 1-hexanol have been measured in a pressure-controlled scanning calorimeter from just above the saturation vapour pressure to 400 Mpa at temperatures from 302.6 K to 503.15 K. The specific volume isotherm, v(T_R,p), at T_R=302.6 K has been derived from measurements of isothermal compressibilities up to 400 MPa and from the specific density at atmospheric pressure. Specific volumes, isothermal compressibilities, thermal pressure coefficients, and isobaric and isochoric heat capacities for the whole pressure and temperature range are derived from these data and from literature data on the saturation vapour pressures and on the isobaric heat capacities at atmospheric or saturation vapour pressure.     

Thermodynamic properties of the azeotropic mixture of acetone and methanol

The molar heat capacities of the pure samples of acetone and methanol, and the azeotropic mixture composed of acetone and methanol were measured with an adiabatic calorimeter in the temperature range 78–320 K. The solid–solid and solid–liquid phase transitions of the pure samples and the mixture were determined based on the curve of the heat capacity with respect to temperature. The phase transitions took place at 126.16±0.68 and 178.96±1.47 K for the sample of acetone, 157.79±0.95 and 175.93±0.95 K for methanol, which were corresponding to the solid–solid and the solid–liquid phase transitions of the acetone and the methanol, respectively. And the phase transitions occurred at 126.58±0.24, 157.16±0.42, 175.50±0.46 and 179.74±0.89 K corresponding to the solid–solid and the solid–liquid phase transitions of the acetone and the methanol in the mixture, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to standard temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature.     

Volumetric properties of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B1) in dilute HCl and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K

Apparent molar volumes and apparent molar isentropic compressibilities of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B₁) were determined from accurately measured density and sound velocity data in water and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K. These volume and compressibility data were extrapolated to zero concentration using suitable empirical or theoretical equations to determine the corresponding infinite dilution values. Apparent molar expansibilities at infinite dilution were determined from slopes of apparent molar volume vs. temperature plots. Ionization of both ascorbic acid and thiamine hydrochloride were suppressed using sufficiently acidic solutions. Apparent molar volumes at infinite dilution for ascorbic acid and thiamine hydrochloride were found to increase with temperature in acidic solutions and in the presence of co-solute, NaCl. Apparent molar expansibility at infinite dilution were found to be constant over the temperature range studied and were all positive, indicating the hydrophilic character of the two vitamins studied in water and in the presence of co-solute, NaCl. Apparent molar isentropic compressibilities of ascorbic acid at infinite dilution were positive in water and in the presence of co-solute, NaCl, at low molalities. Those of thiamine hydrochloride at infinitive dilution were all negative, consistent with its ionic nature. Transfer apparent molar volumes of vitamins at infinite dilution from water solutions to NaCl solutions at various temperatures were determined. The results were interpreted in terms of complex vitamin-water-co-solute (NaCl) interactions.     

Excess Molar Enthalpies of the Ternary System {x1CH3CH2COOCH2CH3+x2CH3(CH2)4CH3+(1-x1-x2)CH3CH2CH2OH} at 298.15 K,and Prediction Using Different Theoric Methods

Abstract

Excess molar enthalpies at the temperature 298.15 K and atmospheric pressure of the ternary mixture {x₁CH₃CH₂COOCH₂CH₃+x₂CH₃(CH₂)₄CH₃+(1-x₁-x₂)CH₃CH₂CH₂OH}and of the involved binary mixtures {xCH₃CH₂COOCH₂CH₃+(1-x)CH₃CH₂CH₂OH} and {xCH₃(CH₂)₄CH₃ + (1-x)CH₃CH₂CH₂OH}were measured using a Calvet microcalorimeter. Variable degree polynomials were fitted to the results. The group contribution models of Nitta-Chao and UNIFAC (versions of Tassios, Larsen and Gmehling) were used to estimate ternary excess enthalpy values, and the results were compared to the experimental data. Several empirical expressions for estimating ternary properties from binary results were also applied.     

Volumetric and acoustic properties of the ternary system (1-butanol+1,4-dioxane+cyclohexane)

Densities and speeds of sound for the ternary system 1-butanol+1,4-dioxane+cyclohexane have been measured at the temperatures of 298.15 and 313.15 K. Excess molar volumes and excess isentropic compressibilities have been calculated from experimental data and fitted by the Redlich-Kister equation for ternary mixtures. The ERAS model has been used to calculate excess molar volumes of the ternary mixture from parameters obtained from the constituent binary mixtures.     

Studies of Thermodynamic Properties of Binary and Ternary Methanolic Solutions Containing KBr and 18-Crown-6 at 298.15 K

Experimental measurements of the speed of sound, density and osmotic vapour pressure are reported for binary 18-Crown-6 (18C6) + CH₃OH, KBr + CH₃OH and ternary KBr + 18C6 + CH₃OH solutions at 298.15 K. The density and compressibility data were processed to obtain the apparent molar volume (ø _V ) and apparent molar isentropic compressibility ( $\phi _{K_S } Experimental measurements of the speed of sound, density and osmotic vapour pressure are reported for binary 18-Crown-6 (18C6) + CH₃OH, KBr + CH₃OH and ternary KBr + 18C6 + CH₃OH solutions at 298.15 K. The density and compressibility data were processed to obtain the apparent molar volume (? _V ) and apparent molar isentropic compressibility () of the solutes in methanol. Expansivity data were obtained for the 18C6 + CH₃OH system from density data at different temperatures and were used for calculation of the isothermal compressibility values at 298.15 K. The isothermal compressibility and expansivity data are further used to obtain the apparent molar isothermal compressibility () and apparent molar expansivity (? _E ) of 18C6 in methanolic solutions and as well as the energy-volume coefficient parameter (∂ U/∂ V) _T in methanol solutions. The volume and compressibility changes due to complexation of KBr with 18C6 are obtained at infinite dilution for ? _V and ? _K . The results are compared with the similar data obtained by us previously for aqueous and CCl₄ solutions. The osmotic coefficient data were used to calculate activities and activity coefficients of each component at 298.15 K as a function of the concentration of binary and ternary methanolic solutions containing KBr and 18C6. The activity and activity coefficient data are used to evaluate the pair and triplet interaction parameters by making appropriate use of the McMillan-Meyer theory of solutions. The calculation of the thermodynamic equilibrium constant (K) is made using the pair interaction parameter, g _NE (non-electrolyte – electrolyte pair interaction), for the complexation equilibria. The nature of interactions present in the CH₃OH solutions is discussed.     

A partial derivatives approach for estimation of the viscosity Arrhenius temperature in N,N-dimethylformamide + 1,4-dioxane binary fluid mixtures at temperatures from 298.15 K to 318.15 K

Excess properties calculated from the literature values of experimental density and viscosity in N,N-dimethylformamide (DMF) + 1,4-dioxane (DO) fluid binary mixtures (from 303.15 to 318.15) K can lead us to test the different correlation equations as well as their corresponding relative functions. Inspection of the Arrhenius activation energy Ea and the enthalpy of activation of viscous flow ?H* shows very close values; here we can define partial molar activation energy Ea₁ and Ea₂ for DMF and DO, respectively, along with their individual contribution separately. Correlation between the two Arrhenius parameters of viscosity in all compositions shows the existence of the primary distinct behaviours separated by particular mole fractions in DMF. In addition, we add that the correlation between Arrhenius parameters reveals interesting Arrhenius temperature (T_A), which is closely related to the vaporisation temperature in the liquid–vapour equilibrium; moreover, the limiting corresponding partial molar properties allow us to estimate the boiling points of the pure components.     

Study on the capacities,heats of dilution and properties of concentrated potassium carnallite solutions at 298.15 K

The heats of dilution of the infinitesimally dilute potassium carnallite solutions at 298.15 K have been studied by continuous titration from 1.8942 to 0.01044 mol·kg^?1, and an equation for the curve of heats of dilution has been fitted. It was shown that the enthalpy of dilution for the same concentration of the carnallite solution is equal to the sum of those of KCl and MgCl₂ solutions. The equation for the curve of enthalpy of dilution corresponds to that of natural carnallite.