Excess molar volumes and viscosities of binary mixtures of cyclohexane and n-alkane at 298.15 K

Awwad, A.M. and Salman, M.A., 1986. Excess molar volumes and viscosities of binary mixtures of cyclohexane and n-alkane at 298.15 K. Fluid Phase Equilibria, 25: 195-208.Excess molar volumes, viscosities, excess molar viscosities, and excess molar activation energies of viscous flow were determined for binary mixtures of cyclohexane + n-pentane, + n-hexane, + n-heptane, + n-octane, + n-nonane, + n-decane, + n-dodecane, + n-tetradecane and + n-hexadecane at 298.15 K. The effect of orientational order of n-alkane on solution molar volumes and viscosities is investigated as well as the adequacy of the Flory theory and free volume theories used to predict solution molar volumes and viscosities. For longer n-alkanes V^E, η^E and ΔG*^E are positive and associated with the orientational order.     

Thermodynamics of liquid mixtures containing a very strongly polar compound: Part 6. DISQUAC characterization of N,N-dialkylamides

Systems of N,N di(n-alkylamides) (hereafter, N,N-dialkylamides) with alkane, benzene, toluene, 1-alkanol or 1-alkyne have been investigated in the framework of the DISQUAC model. The corresponding interaction parameters are reported. They change regularly with the molecular structure of the mixture components. This variation is similar to those encountered when treating other systems in terms of DISQUAC. The model describes consistently a whole set of thermodynamic properties: liquid–liquid equilibria (LLE), vapor–liquid equilibria (VLE), solid–liquid equilibria (SLE), molar excess Gibbs energies (G^E), molar excess enthalpies (H^E), molar excess heat capacities at constant pressure (C_P^E), partial molar excess properties at infinite dilution, enthalpies and heat capacities. The model also provides good results for the Kirkwood–Buff integrals and for the linear coefficients of preferential solvation. For ternary systems, DISQUAC predictions on VLE and H^E, obtained using binary parameters only, are in good agreement with the experimental data. A short comparison between DISQUAC and Dortmund UNIFAC results is shown. DISQUAC improves UNIFAC results on H^E and C_P^E, magnitudes which strongly depend on the molecular structure. The investigated mixtures behave similarly to those characterized by thermodynamic properties which arise from dipolar interactions. Association/solvation effects do not play, as a whole, an important role in the studied systems. This may explain that the ERAS model fails when representing the thermodynamic properties of dimethylformamide + 1-alkanol mixtures.     

Excess Gibbs free energies and excess enthalpies for triethylamine + n-hexane,triethylamine + n-octane,and tributylamine + n-hexane at 298.15 K

Total vapour pressures have been measured by the isoteniscope method for triethylamine + n-hexane, triethylamine + n-octane, and tributylamine + n-hexane at 298.15 K. The excess Gibbs free energies G^E for the liquid phase have been calculated from the measurements; G^E is positive for the triethylamine systems and negative for the tributylamine system. The excess enthalpies H^E for these three mixtures and for tributylamine + n-octane have been measured at the same temperature. Except for tributylamine + n-hexane, all these H^E's are positive.     

Excess enthalpies of some aromatic aldehydes in n-hexane, n-heptane and benzene

Calorimetric measurements of molar excess enthalpies, H^E, at 298.15 K, of mixtures containing aromatic aldehydes of general formula C₆H₅(CH₂)_mCHO (with m = 0, 1 and 2) + n-hexane, n-heptane or benzene are reported, together with the values of H^E at equimolar composition compared with the corresponding values of H^E for the aromatic ketones in the same solvents. The experimental results clearly indicate that the intermolecular interactions between the carbonyl groups (CHO) are influenced by the intramolecular interactions between the carbonyl and phenyl groups, particularly for the mixtures containing benzaldehyde.     

Thermodynamic properties of binary mixtures containing n-alkylamines: I. Isothermal vapour–liquid equilibrium and excess molar enthalpy of n-alkylamine+toluene mixtures. Measurement and analysis in terms of group contributions

Molar excess enthalpies, H^E, at 303.15 K and atmospheric pressure, of n-propyl-, n-butyl-, n-pentyl-, n-octyl- or n-decylamine+toluene, as well as the isothermal vapour–liquid equilibria, VLE, of n-butylamine+toluene and of n-butylamine+benzene at 298.15 K have been determined. These experimental results, along with the data available in the literature on molar excess Gibbs energies, G^E, activity coefficients at infinite dilution, γ_i^∞, and molar excess enthalpies, H^E, for n-alkylamine+toluene mixtures are examined on the basis of the DISQUAC group contribution model. The modified UNIFAC is also used to describe the mixtures.     

The vapour pressure behaviour and the association of N-methylethylamine,diethylamine and their N-deuterioanalogues in mixtures with n-hexane

The vapour pressure isotherms of mixtures of N-methylethylamine and N-methyl(N-²H)ethylamine with n-hexane have been measured between 273 and 323 K. The vapour pressure isotherms of mixtures of diethylamine and (N-²H)diethylamine with nhexane between 293 and 353 K have also been measured. In addition, the vapour pressures of the pure amines have been determined down to 228 or 243 K. As evidenced by the small values for the Wilson coefficients, the activity coefficients, the Gibbs free energies and the data derived from the theory of ideal associated solutions, the association of diethlamine is very weak; that of N-methylethylamine is not much larger. The observations on the vapour pressure isotope effect of the two amines and their N-deuterioanalogues are compatible with this interpretation. The normal effect is smaller for diethylamine, with ratios P_D/P_H of 0.972–0.997 between 243 and 323 K, than for N-methylethylamine with values of 0.965–0.991, and the partial pressure quotients calculated for mixtures of the two compounds with n-hexane show the transition from the normal to the inverse effect on low dilution. The data for the N-deuterioanalogues and their mixtures with n-hexane suggest a somewhat greater energy of the deuterium bonds.     

Topological and thermodynamic investigations of binary mixtures: Molar excess volumes, molar excess enthalpies and isentropic compressibility changes of mixing

Molar excess volumes, V^E, molar excess enthalpies, H^E, and speeds of sound, u, of o-toluidine (i) + cyclohexane or n-hexane or n-heptane (j) binary mixtures have been determined over entire range of composition at 308.15 K. Speeds of sound data have been utilized to predict isentropic compressibility changes of mixing, of (i + j) mixtures. The observed V^E, H^E and data have been analyzed in terms of Graph theory. The analysis of V^E data by Graph theory reveals that o-toluidine exists as an associated molecular entity and (i + j) mixtures contain 1:1 molecular complex. It has been observed that V^E, H^E and values calculated by Graph theory compare well with their corresponding experimental values. The observed data have also been analyzed in term of Flory theory.     

Isothermal vapor–liquid equilibria and excess molar volumes for the ternary mixtures containing 2-methyl pyrazine

Isothermal vapor–liquid equilibrium (VLE) data at 353.15 K and excess molar volumes (V^E) at 298.15 K are reported for the binary systems of ethyl acetate (EA)+cyclohexane and EA+n-hexane and also for the ternary systems of EA+cyclohexane+2-methyl pyrazine (2MP) and EA+n-hexane+2MP. The experimental binary VLE data were correlated with common g^E model equations. The correlated Wilson parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson parameters were compared with experimental ternary data. The experimental excess molar volumes were correlated with the Redlich–Kister equation for the binary mixtures, and Cibulka’s equation for the ternary mixtures.     

Refractive Indices Measurement and Correlation for Selected Binary Systems of Various Polarities at 25 °C

New refractive indices at 25 °C were measured and are reported here for 19 binary mixtures of pentan-3-one+1,2-dichloroethane, +1,3-dichloropropane, +1,4-dichlorobutane, +trichloromethane, +1,1,1-trichloroethane, +1,1,2,2-tetrachloroethane; cyclopentanone+1-chlorobutane, +1,1,2,2-tetrachloroethane; cyclohexanone+1,1,2,2-tetrachloroethane; 5-chloro-2-pentanone+n-hexane, +toluene, +ethylbenzene; nitromethane+trichloromethane; and nitromethane or nitroethane, +1,2-dichloroethane, +1,3-dichloropropane, +1,4-dichlorobutane. The experimental refractive index deviations from linear mixing behavior have been evaluated and correlated consistently with the 3-parameter Redlich–Kister equation with good results. The molar refraction was also examined for the systems including pentan-3-one, cyclopentanone, cyclohexanone and 5-chloro-2-pentanone for which densities and excess molar volumes are available from previous works. Different theoretical (n, ρ) mixing rules were tested for these systems. The excess Gibbs energy G ^E and excess enthalpy H ^E values were considered together with the excess molar volumes V ^E, excess refractive indexes $ n_{\text{D}}^{\text{E}} $ , molar refraction R and excess molar refractions R ^E on mixing in the discussion of the influence of the alkyl chain length or of the nature of the second component in the mixture in terms of molecular interactions.     

Thermodynamic properties of binary mixtures containing n-alkylamines: II. Isothermal vapour–liquid equilibrium and excess molar enthalpy of n-alkylamine+ethylbenzene mixtures. Measurement and analysis in terms of group contributions

Molar excess enthalpies, H^E, at 303.15 K and atmospheric pressure, of n-propyl-, n-butyl-, n-pentyl-, n-octyl- or n-decylamine+ethylbenzene, as well as the isothermal vapour–liquid equilibrium (VLE) of n-butylamine+ethylbenzene at 298.15 K have been determined. These experimental results, along with the data available in the literature on molar excess Gibbs energies, G^E, for n-alkylamine+ethylbenzene mixtures are examined on the basis of the DISQUAC group contribution model. The modified (mod.) UNIFAC is also used to describe the mixtures.     

Topological aspects of the thermodynamics of binary mixtures of non-electrolytes

An approach based on the “graph” theory has been evolved to predict molar excess enthalpies, H^E, and molar excess volumes, V^E, for a number of binary mixtures of non-electrolytes. The calculated H^E and V^E values compare reasonably well with their corresponding experimental values. The limitations of this approach have also been discussed.     

Excess molar volumes and dynamic viscosities for binary mixtures of toluene + n-alkanes (C5–C10) at T = 298.15 K – Comparison with Prigogine–Flory–Patterson theory

Densities ρ, dynamic viscosities η, for binary mixtures of toluene with some n-alkanes, namely, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane have been measured over the complete composition range. Excess molar volumes V^E, viscosity deviations Δη, and excess Gibbs free energy of activation ΔG^1E, were calculated there from and were correlated by Redlich–Kister type function in terms of mole fractions. For mixtures of toluene with n-pentane and n-hexane the V^E is negative and for the remaining systems is positive. The Δη values are negative for all the studied mixtures. The ΔG^1E values shows the positive values for the binary mixtures with n-decane, whereas the negative values have been observed for all the remaining binary mixtures. From the results, the excess thermal expansivities at constant pressure α^E, is also estimated. The Prigogine–Flory–Patterson (PFP) theory and its applicability in predicting V^E is tested. The results obtained for viscosity of binary mixtures were used to test the semi-empirical relations of Grunberg and Nissan, Tamura and Kurata, Hind et al., Katti and Chaudhri, McAllister, Heric, Kendall, and Monroe. The experimental on the constituted binaries are analyzed to discus the nature and strength of intermolecular interactions in these mixtures.     

Liquid Solution Densities of Ternary-Pseudobinary Mixtures of (Benzene + Cyclohexane) in the Presence of Tetrachloromethane or <Emphasis Type="Italic">n</Emphasis>-Hexane

Densities have been obtained as a function of composition for ternary-pseudobinary mixtures of [(benzene + tetrachloromethane or n-hexane) + (cyclohexane + tetrachloromethane or n-hexane)] at atmospheric pressure and the temperature 298.15 K, by means of a vibrating-tube densimeter. Excess molar volumes, V_m^E, partial molar volumes and excess partial molar volumes were calculated from the density data. The values of V_m^E have been correlated using the Redlich–Kister equation and the coefficients and standard errors were estimated. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show that the third component, CCl₄ or n-C₆H₁₄, have quite different influences on the volumetric properties of binary liquid mixtures of benzene with cyclohexane.     

Thermodynamics of binary mixtures containing aldehydes. excess enthalpies of n-alkanals + benzene and + tetrachloromethane mixtures

Molar excess enthalpies H^E have been measured as a function of mole fraction at atmospheric pressure and 298.15 K for the binary liquid mixtures of ethanal, propanal, butanal and pentanal + benzene or + tetrachloromethane. The results show that the excess enthalpies decrease with increasing the n-alkanal chain length, with negative values for n-pentanal.     

Experimental enthalpies of mixtures of alkylfluoroethers + n-alkanes at 298.15 K

In this work, excess molar enthalpies, H_m^E, at 298.15 K and atmospheric pressure of methylnonafluorobutylether + alkane (hexane, octane, decane, dodecane) and ethylnonafluorobutylether + alkane (hexane, octane, decane, dodecane) are reported. Values of excess molar enthalpies were measured using a Calvet microcalorimeter. The binary experimental data were fitted using a Redlich–Kister variable-degree polynomial. The excess molar enthalpy is positive for all the mixtures. Phase separation is found in the range of 0.3<x<0.8 and 0.3<x<0.94 for the mixtures methylnonafluorobutyl ether + (decane, or dodecane), respectively.     

Excess heat capacities of binary mixtures of carbon tetrachloride with n-alkanes at 298.15 K

A Picker flow microcalorimeter was used to determine molar excess heat capacities C_P^E at 298.15 K for mixtures of carbon tetrachloride + n-heptane, n-nonane, and n-decane. The excess heat capacities are negative in all cases. The absolute value |C_P^E| increases with increasing chain length of the alkane. A formal interchange parameter, c_P12, is calculated and its dependence on n-alkane chain length is discussed briefly in terms of molecular orientations.     

Calorimetric effects of short-range orientational order in solutions of benzene or n-alkylbenzenes in n-alkanes

A Picker flow microcalorimeter was used to determine molar excess heat capacities, C^E_p, at 298.15 K, as function of concentration, for the eleven liquid mixtures: benzene+n-tetradecane; toluene+n-heptane, and +n-tetradecane; ethylbenzene+n-heptane, +n-decane, +n-dodecane; and +n-tetradecane; n-propylbenzene +n-heptane, and +n-tetradecane; n-butylbenzene+n-heptane, and +n-tetradecane. In addition, molar excess volumes, V^E, at 298.15 K, were obtained for each of these systems (except benzene+n-tetradecane) and for toluene+n-hexane. The excess volumes which are generally negative with a short alkane, increase and become positive with increasing chain length of the alkane. The excess heat capacities are negative in all cases. The absolute ¦C^E_p¦ increased with increasing chain length of the n-alkane. A formal interchange parameter, C_p12, is calculated and its dependence on n-alkane chain length is discussed in terms of molecular orientations.     

Densities and excess molar volumes of the ternary mixture (1-butanol+n-hexane+1-chlorobutane) at 298.15 and 313.15 K. Application of the ERAS model

Densities of the liquid mixtures (n-hexane+1-chlorobutane) and (1-butanol+n-hexane+1-chlorobutane) have been measured by the vibrating tube technique at 298.15 K and 313.15 K. With these densities, excess molar volumes were calculated. An extended version of the so-called ERAS model has been used for describing V^E of the complete ternary system at 298.15 K. Qualitatively the ERAS-model gives an adequate representation of this system, being similar the shapes of both the experimental and the predicted curves.