Volumetric and viscometric behaviour of binary systems: (1-hexanol + hydrocarbons)

Densities and viscosities of binary liquid mixtures of (1-hexanol  + n -hexane, or cyclohexane, or benzene) have been measured at a number of mole fractions at T =  (303, 313, and 323) K. The excess molar volume V_m^Eand apparent molar volume V_φhave been calculated from the density data. TheV_m^E anddV_m^E / dT for the system, (1-hexanol  + n -hexane) have been found negative, while those for the systems, (1-hexanol  +  cyclohexane) and (1-hexanol  +  benzene), were found to be positive. Excess viscosities η^Ecalculated from viscosity data, have been found to be negative over the whole composition range at the temperatures studied for all the three systems. Volumetric and viscometric behaviours indicate that dispersion is the major force of interaction between the components in (1-hexanol  +  cyclohexane, or benzene), while inclusion of hydrocarbon chains into the interstices of polymolecular ring structures of alcohol formed by hydrogen bonding has been assumed to play a significant role apart from dispersion in the system (1-hexanol  + n -hexane). Thermodynamic parameters of activation for viscous flow have been calculated from the viscosity data at different temperatures and a possible explanation suggested.     

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.     

Thermodynamic properties of (a pentyl ester + an-alkane). XIV. The HmEand VmEfor (an ester + an-alkane)

This paper presents experimental data for the excess molar enthalpies H_m^Eand excess molar volumes V_m^Eat T =  298.15 K and atmospheric pressure for 21 binary mixtures consisting of one of three pentyl esters (ethanoate, propanoate, and pentanoate) and one of seven odd n -alkanes (from pentane to heptadecane). The results have shown the mixing of these mixtures to be endothermic, with H_m^Evarying uniformly with the n -alkane chain length. The variation of V_m^Ewas also found to be uniform, with contraction effects observed for the mixtures that contained low molecular-weight hydrocarbons, and increasing with the pentyl ester chain length. Different group-contribution theories were used to calculate the excess properties for (an ester  +  an n -alkane). Comparison of the calculated and experimental results revealed that, in most cases, the differences increased with the molecular weight of the components. However, the differences for the calculated values of the excess volumes using the model of Nitta et al. decreased with n -alkane chain length but increased with ester chain length, the mean differences for the excess volumes being larger than 20 per cent.     

Volumetric properties of (an organic compound + di-n-butyl ether) atT = 298.15 K

Excess molar volumes V_m^Eof {di- n -butyl ether (DBE)  +  a monofunctional organic compound} have been determined atT =  298.15 K over the whole composition range by means of a vibrating-tube densimeter. TheV_m^E values were either positive (propylamine, or butylamine, or acetone, or tetrahydrofuran  +  DBE) or negative (methanol, or butanol, or diethyl ether, or cyclopentanone, or acetonitrile  +  DBE). Markedly asymmetric V_m^Ecurves were displayed by (DBE  +  methanol) and (DBE  +  acetonitrile). Partial molar volumes __ V_m^oat infinite dilution in DBE, both from this work and the literature, were analysed in terms of an additivity scheme, and the group contributions thus obtained were discussed and compared with analogous results in water. DBE revealed a greater capability of distinguishing between polar and non-polar solutes, as well as in discriminating differently shaped molecules (unbranched, branched, cyclic). The limiting slopes of apparent excess molar volumes are evaluated and briefly discussed in terms of solute–solute and solute–solvent interactions.     

Thermodynamic properties of (tetradecane + benzene, + toluene, + chlorobenzene, + bromobenzene, + anisole) binary mixtures at T = (298.15, 303.15, and 308.15) K

Density ρ, viscosity η, and refractive index n_D, values for (tetradecane + benzene, + toluene, + chlorobenzene, + bromobenzene, + anisole) binary mixtures over the entire range of mole fraction have been measured at temperatures (298.15, 303.15, and 308.15) K at atmospheric pressure. The speed of sound u has been measured at T = 298.15 K only. Using these data, excess molar volume V^E, deviations in viscosity Δη, Lorentz–Lorenz molar refraction ΔR, speed of sound Δu, and isentropic compressibility Δk_s have been calculated. These results have been fitted to the Redlich and Kister polynomial equation to estimate the binary interaction parameters and standard deviations. Excess molar volumes have exhibited both positive and negative trends in many mixtures, depending upon the nature of the second component of the mixture. For the (tetradecane + chlorobenzene) binary mixture, an incipient inversion has been observed. Calculated thermodynamic quantities have been discussed in terms of intermolecular interactions between mixing components.     

Volumetric properties of ternary (IL + 2-propanol or 1-butanol or 2-butanol + ethyl acetate) systems and binary (IL + 2-propanol or 1-butanol or 2-butanol) and (1-butanol or 2-butanol + ethyl acetate) systems

The experimental densities for the binary or ternary systems were determined at T = (298.15, 303.15, and 313.15) K. The ionic liquid methyl trioctylammonium bis(trifluoromethylsulfonyl)imide ([MOA]⁺[Tf₂N]⁻) was used for three of the five binary systems studied. The binary systems were ([MOA]⁺[Tf₂N]⁻ + 2-propanol or 1-butanol or 2-butanol) and (1-butanol or 2-butanol + ethyl acetate). The ternary systems were {methyl trioctylammonium bis(trifluoromethylsulfonyl)imide + 2-propanol or 1-butanol or 2-butanol + ethyl acetate}. The binary and ternary excess molar volumes for the above systems were calculated from the experimental density values for each temperature. The Redlich–Kister smoothing polynomial was fitted to the binary excess molar volume data. Virial-Based Mixing Rules were used to correlate the binary excess molar volume data. The binary excess molar volume results showed both negative and positive values over the entire composition range for all the temperatures.The ternary excess molar volume data were successfully correlated with the Cibulka equation using the Redlich–Kister binary parameters.     

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.     

Excess molar volume and viscosity study for the ternary system tetrahydrofuran (1) + 1-chlorobutane (2) + 2-butanol (3) at 283.15, 298.15 and 313.15 K

This work reports the measured density, ρ, and viscosity, η, values of liquid mixtures of tetrahydrofuran (1) + 1-chlorobutane (2) + 2-butanol (3) at temperatures of 283.15, 298.15 and 313.15 K over a range of mole fractions and atmospheric pressure. Excess molar volume, V^E, viscosity deviations, Δη, and excess free energies of activation of viscous flow, ΔG^*E, have been calculated from experimental data and fitted to Cibulka, Singh et al. and Nagata and Sakura equations. The results were analyzed in terms of the molecular interaction between the components of the mixtures. Excess molar volumes and viscosity deviations were predicted from binary contributions using geometrical solution models, Tsao and Smith; Jacob and Fitzner; Kholer; Rastogi et al.; Radojkovic et al. Finally, experimental results are compared with those obtained by applying group-contribution method proposed by Wu.     

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.     

Excess molar volumes of (an alkane + 1-chloroalkane) atT = 298.15 K

The densities of the following: (pentane  +  1-chloropropane, or 1-chlorobutane, or 1-chloropentane, or 1-chlorohexane), (hexane  +  1-chloropropane, or 1-chlorobutane, or 1-chloropentane, or 1-chlorohexane), (heptane  +  1-chloropropane, or 1-chlorobutane, or 1-chloropentane, or 1-chlorohexane), (octane  +  1-chloropropane, or 1-chlorobutane, or 1-chloropentane, or 1-chlorohexane), were measured at T =  298.15 K by means of a vibrating-tube densimeter. The excess molar volumes V_m^E, calculated from the density data, are negative for (pentane  +  1-chloropentane, or 1-chlorohexane) and (hexane  +  1-chlorohexane) over the entire range of composition. (Pentane  +  1-chlorobutane), (hexane  +  1-chloropentane) and (heptane  +  1-chlorohexane) exhibit an S-shapedV_m^E dependence. For all the other systems,V_m^E is positive. The V_m^Eresults were correlated using the fourth-order Redlich–Kister equation, with the maximum likelihood principle being applied for determining the adjustable parameters.     

Thermodynamic study of (heptane + amine) mixtures. II. Excess and partial molar volumes at 298.15 K

Excess molar volumes V^E at 298.15 K were determined by means of a vibrating tube densimeter for binary mixtures of heptane + primary n-alkyl (C₃ to C₁₀) and branched amines (iso-propyl-, iso-, sec-, and tert-butyl-, iso-, tert-pentyl-, and pentan-3-amine) in the whole composition range. The apparent molar volumes of solid dodecyl- and tetradecylamine in heptane dilute solution were also determined. The V^E values were found positive for mixtures involving C₃ to C₈ linear amines, with V^E decreasing with chain lengthening. Heptane + nonyl and decylamine showed s-shaped, markedly asymmetric, curves. Mixtures with branched C₃ to C₅ amines displayed positive V^E’s larger than those observed in the mixtures of the corresponding linear isomers. Partial molar volumes V° at infinite dilution in heptane were evaluated for the examined amines and compared with those of alkanes and alkanols taken from the literature. An additivity scheme, based on the intrinsic volume approach, was applied to estimate group (CH₃, CH₂, CH, C, NH₂, and OH) contributions to V°. The effect of branching on V° and the limiting slope of the apparent excess molar volumes were evaluated and discussed in terms of solute–solvent and solute–solute interactions.     

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.     

Thermodynamic properties of mixing for (1-alkanol + an-alkane + a cyclic alkane) atT = 298.15 K. I. (n-Hexane + cyclohexane + 1-butanol)

Experimental values of density, refractive index and speed of sound of (hexane  +  cyclohexane  +  1-butanol) were measured at T =  298.15 K and atmospheric pressure. From the experimental data, the corresponding derived properties (excess molar volumes, changes of refractive index on mixing and changes of isentropic compressibility) were computed. Such derived values were correlated using several polynomial equations. Several empirical methods were used in the calculation of the properties of ternary systems from binary data. The Nitta–Chao group contribution model was applied to predict excess molar volume for this mixture.     

(Vapour + liquid) equilibria and excess molar enthalpies for mixtures with strong complex formation. Trichloromethane or 1-bromo-1-chloro-2,2,2-trifluoroethane (halothane) with tetrahydropyran or piperidine

Isothermal (vapour  +  liquid) equilibria were measured for (trichloromethane  +  tetrahydropyran or piperidine) at T =  333.15 K and {1-bromo-1-chloro-2,2,2-trifluoroethane (halothane)  +  tetrahydropyran or piperidine} atT =  323.15 K with a circulation still. The results were verified by effective statistical procedures and used to calculate activity coefficients and excess molar Gibbs free energiesG_m^E . Excess molar enthalpiesH_m^E for these mixtures were determined at T =  298.15 K by means of an isothermal CSC microcalorimeter equipped with recently reconstructed flow mixing cells. Reliable performance of the calorimetric setup was proved by the good agreement of H_m^Efor (hexane  +  cyclohexane), (2-propanone  +  water), and (methanol  +  water), with the best literature results. The trichloromethane- or halothane-containing mixtures exhibit strong negative deviations from Raoult’s law and are highly exothermic, thus indicating that complex formation via hydrogen bonding is a governing nonideality effect. A close similarity in the behaviour of corresponding mixtures with trichloromethane and halothane is observed, but for halothane-containing mixtures,G_m^E and H_m^Eare consistently more negative, confirming that halothane is a more powerful proton donor than chloroform.     

Thermodynamics of isomeric hexynes + MTBE binary mixtures

The vapor pressures of liquid hex-1-yne or hex-2-yne + methyl 1,1-dimethylethyl ether (MTBE) binary mixtures and of the three pure components were measured by a static method at several temperatures between 263 and 343 K. These data were correlated with the Antoine equation. Excess molar Gibbs energies G^E were calculated for several constant temperatures, taking into account the vapor-phase imperfection in terms of the second molar virial coefficients, and were fitted to the Redlich–Kister equation. Calorimetric excess enthalpy H^E measurements, for these binary mixtures, are also reported at 298.15 K. The experimental VLE and H^E data were used, examining the binary mixtures hex-1-yne or hex-2-yne + MTBE in the framework of the DISQUAC and modified UNIFAC (Do) models. The DISQUAC calculations, reporting a new set of interaction parameters for the contact carbon–carbon triple bond/oxygen ether, is regarded as a preliminary approach.     

Density,speed of sound and refractive index of (n-hexane + cyclohexane + 1-hexanol) atT = 298.15 K

Densities, speeds of sound and refractive indices have been measured for (n -hexane  +  cyclohexane  +  1-hexanol) and its corresponding binaries atT =  298.15 K. In addition, ideal isentropic compressibilities were calculated from the speeds of sound, densities, and literature heat capacities and cubic expansion coefficients. The excess molar volumes and excess isentropic compressibilities, and deviations of the speed of sound and refractive index are correlated by polynomials and discussed.The Nitta–Chao model was used to estimate binary and ternary excess molar volumes, and several empirical equations were also used to calculate the excess and deviation properties.     

Excess properties and vapour pressure of {3-diethylaminopropylamine + cyclohexane}

The vapour pressures of liquid {3-diethylaminopropylamine (3-DEPA) + cyclohexane} were measured by a static method between T = (273.15 and 363.15) K at 10 K intervals. The excess molar volumes V^E at 298.15 K and excess molar enthalpies H^E at 303.15 K were also measured. The molar excess Gibbs free energies G^E were obtained with Barker’s method and fitted to the Redlich–Kister equation. The Wilson equation was also used. Deviations between experimental and predicted G^E and H^E, by using DISQUAC model, were evaluated     

Excess molar enthalpies of ternary mixtures (dibutyl ether or dipropyl ether + 2,2-dimethylbutane + 2,3-dimethylbutane) at the temperature 298.15 K

Excess molar enthalpies, measured at the temperature 298.15 K and atmospheric pressure conditions by means of a flow microcalorimeter, are reported for the ternary mixtures {x₁(dibutyl ether or dipropyl ether) + x₂ 2,2-dimethylbutane + (1 ? x₁ ? x₂) 2,3-dimethylbutane}. A smooth representation of the results is described and the constant-enthalpy contours for each ternary system are displayed on the respective Roozeboom diagrams. The results serve to show that good estimates of the excess molar enthalpies of the ternary systems can be obtained from the Liebermann–Fried model by using the physical properties of the constituent pure components and the parameters determined from the binary mixtures of these components.     

(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.