Excess Molar Volumes and Excess Isentropic Compressibilities of o-Toluidine + Tetrahydropyran with Pyridine or Benzene or Toluene Ternary Mixtures at 298.15, 303.15 and 308.15 K

The densities, ρ ₁₂₃, and speeds of sound, u ₁₂₃, of ternary o-toluidine (OT, 1) + tetrahydropyran (THP, 2) + pyridine (Py) or benzene or toluene (3) mixtures have been measured as a function of composition at 298.15, 303.15 and 308.15 K. Values of the excess molar volumes, $ V_{123}^{\text{E}} , $ and excess isentropic compressibilities, $ (\kappa_{\text{S}}^{\text{E}} )_{123} , $ of the studied mixtures have been determined by employing the measured experimental data. The observed thermodynamic properties were fitted with the Redlich–Kister equation to determine adjustable ternary parameters and standard deviations. The $ V_{123}^{\text{E}} $ and $ (\kappa_{\text{S}}^{\text{E}} )_{123} $ values were also analyzed in terms of Graph theory. It was observed that Graph theory correctly predicts the sign as well as magnitude of $ V_{123}^{\text{E}} $ and $ (\kappa_{\text{S}}^{\text{E}} )_{123} $ values of the investigated mixtures. Analysis of the data suggests strong interactions and a more close packed arrangement in OT (1) + THP (2) + Py (3) mixtures as compared to those of the OT (1) + THP (2) + benzene (3) or toluene (3) mixtures. This may be due to the presence of a nitrogen atom in Py which results in stronger interactions for the OT:THP molecular entity as compared to those with benzene or toluene.     

Measurements of the Molar Heat Capacities and Excess Molar Heat Capacities for Water + Organic Solvents Mixtures at 288.15 K to 303.15 K and Atmospheric Pressure

Experimental molar heat capacity data (Cp _m) and excess molar heat capacity data (Cp^E_m\mathit{Cp}^{\mathrm{E}}_{\mathrm{m}}) of binary mixtures containing water + (formamide or N,N-dimethylformamide or dimethylsulfoxide or N,N-dimethylacetamide or 1,4-dioxane) at several compositions, in the temperature range 288.15 K to 303.15 K and atmospheric pressure, have been determined using a modified 1455 PAAR solution calorimeter. The excess heat capacities are positive for aqueous solutions containing 1,4-dioxane, N,N-dimethylformamide or dimethylsulfoxide, negative for solutions containing water + formamide and show a sigmoid behavior for mixtures containing water + N,N-dimethylacetamide, over the whole composition range. The experimental excess molar heat capacities are discussed in terms of the influence of temperature and of the organic solvent type present in the binary aqueous mixtures, as well as in terms of the existing molecular interactions and the organic solvent’s molecular size and structure.     

Measurement and Correlation of Excess Molar Enthalpy of Binary Mixtures Containing Butyl Acetate + 1-Alkanols (C1–C6) at 298.15 K

Excess molar enthalpies, ?H _m ^E , for the binary mixtures of butyl acetate + 1-alkanols, namely (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol), were measured over the whole range of composition at 298.15 K using a Parr 1455 solution calorimeter. The excess partial molar enthalpies, ?H _m,i ^E , were calculated from the experimental excess molar enthalpies using the Redlich–Kister polynomial equation. The sign of ?H _m ^E for all systems are positive because of the disruption of hydrogen bonding and dipole–dipole interactions in the alkanols and esters, respectively. The magnitude of the ?H _m ^E values increases with increasing alkyl chain length. The behavior of ?H _m ^E was analyzed in terms of the length of the alkanol chain, the nature and type of intermolecular interactions and the balance between positive and negative effects on deviations from ideality. The experimental excess molar enthalpy data have also been correlated using the Redlich–Kister and SSF equations and two local composition models (UNIQUAC and NRTL).     

Excess Molar Volumes of Ternary Mixtures of a Cyclic Ether with Aromatic Hydrocarbons at 308.15 K

Excess molar volumes, V_ijk^EV_{ijk}^{E}, are reported for ternary mixtures of tetrahydropyran (i)+benzene (j)+toluene or o- or p-xylenes (k) and tetrahydropyran (i)+toluene (j)+o- or p-xylenes (k) as a function of composition at 308.15 K. These V_ijk^EV_{ijk}^{E} values have been fitted to the Redlich–Kister equation to predict ternary adjustable parameters and standard deviations. The measured V_ijk^EV_{ijk}^{E} data have been analyzed in terms of Graph theory (which involves the topology of the constituents of mixtures). It has been observed that V_ijk^EV_{ijk}^{E} values predicted by Graph theory compare well with their corresponding experimental values.     

Densities and Excess Molar Volumes of Binary and Ternary Mixtures Containing Acetonitrile + Acetophenone + 1,2-Pentanediol: Experimental Data,Correlation and Prediction by PFP Theory and ERAS Model

Densities were determined experimentally over the entire range of composition at 298.15 K for the ternary system acetonitrile (1) + acetophenone (2) + 1,2-pentanediol (3) and for the three corresponding binary systems. Excess molar volumes were calculated for the binary and the ternary systems. These results were fitted to variable-degree polynomials. Further, the Prigogine-Flory-Patterson (PFP) theory and Extended Real Associated Solution (ERAS) model were applied to V_m^EV_{m}^{\mathrm{E}} for the binary mixtures of acetonitrile + acetophenone, acetonitrile + 1,2-pentanediol and acetophenone + 1,2-pentanediol, and the findings compared with the experimental results.     

Excess Molar Volumes and Viscosities for Binary Mixtures of 1-Alkoxypropan-2-ols with 1-Butanol, and 2-Butanol at 298.15 K and Atmospheric Pressure

Excess molar volumes Vm^E and kinematic viscosities v have been measured as a function of composition for binary mixtures of propylene glycol monomethyl ether （1-methoxy-2-propanol）, MeOCH2CH（OH）Me, propylene glycol monoethyl ether （1-ethoxy-2-propanol）, EtOCH2CH（OH）Me, propylene glycol monopropyl ether （1-propoxy-2-propanol）, PrOCH2CH（OH）Me, propylene glycol monobutyl ether （1-butoxy-2-propanol）, BuOCH2CH（OH）Me, and propylene glycol tert-butyl ether （1-tert-butoxy-2-propanol）, t-BuOCH2CH（OH）Me with 1-butanol, and 2-butanol, at 298.15 K and atmospheric pressure. The excess molar volumes are negative across the entire range of composition for all the systems with 1-butanol, and positive for the systems 2-butanol＋ 1-methoxy-2-propanol, and ＋1-propoxy-2-propanol, negative for the systems 2-butanol＋1-butoxy-2-propanol, and change sign for the systems 2-butanol＋ 1-ethoxy-2-propanol, and ＋ 1-tert-butoxy-2-propanol. From the experimental data, the deviation in dynamic viscosity η from ∑χiηi has been calculated. Both excess molar volumes and viscosity deviations have been correlated using a Redlich-Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors.     

Excess Molar Volumes, Excess Molar Enthalpies, and Excess Isentropic Compressibilities of Binary Mixtures Containing N-Methyl-2-Pyrrolidone and Isomeric Xylenes at 308.15?K

Excess molar volumes, excess molar enthalpies and speeds of sound of 1-methyl pyrrolidin-2-one?+?o- or m- or p-xylene binary mixtures have been measured over the entire composition range at 308.15?K. The speed of sound data were used to determine the excess isentropic compressibilities. It is observed that while the values of the excess molar enthalpies for the investigated mixtures are positive, the values of the excess molar volumes and excess isentropic compressibilities are negative over the entire composition range. The measured thermodynamic data have been analyzed in terms of Graph, Prigogine?CFlory?CPatterson, and the Sanchez and Lacombe theories. It is observed that Graph theory correctly predicts the signs and magnitudes of the excess molar volumes, excess molar enthalpies, and excess isentropic compressibilities of the studied mixtures. However, the excess molar volumes, excess molar enthalpies and excess isentropic compressibilities predicted by Prigogine?CFlory?CPatterson and Sanchez and Lacombe theories are of same sign.     

Volumetric Properties of 1,3-Dioxolane + Toluene + o- or p-Xylene Ternary Mixtures at 25.00 °C and Atmospheric Pressure

Excess molar volumes, $ V_{123}^{\text{E}} $ V 123 E , of 1, 3-dioxolane (1) + toluene (2) + o- or p-xylene (3) ternary mixtures have been determined dilatometrically over the entire composition range at 298.15 K. For thermodynamic consistency the experimental values were fitted to Redlich–Kister Equation. The $ V_{123}^{\text{E}} $ V 123 E values of 1, 3-dioxolane (1) + toluene (2) + o- or p-xylene (3) ternary mixtures have been found to be negative over the whole composition range. It has been observed that $ V_{123}^{\text{E}} $ V 123 E values calculated by graph theory are of the same sign and magnitude with respect to their experimental values.     

Activity Coefficient Determination for the Ternary Systems CsCl in N-Methylformamide or Urea + Water Mixtures at T = 298.15 K

The mean activity coefficients for CsCl in N-methylformamide or urea (w) + H₂O (1 ? w) systems were determined in this work by potentiometry, using ion-selective electrodes at 298.15 K. The value of mass fraction w was varied between 0.00 and 0.40 in five unit-steps and the molality of CsCl was between 0.0020 and 1.4009 mol·kg^?1. The experimental data have been correlated with the Pitzer, modified Pitzer and the extended Debye–Hückel equations. The resulting values of the mean activity coefficients, the osmotic coefficients and the standard Gibbs energy of transfer, together with the Pitzer ion-interaction parameters (β ⁽⁰⁾, β ⁽¹⁾ and C ^φ), extended Debye–Hückel parameters (a, c and d), and modified Pitzer parameters (b, B _MX, C _MX) are reported for the investigated systems.     

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.     

Physico-chemical Properties of Binary and Ternary Mixtures of Ethyl Acetate + Ethanol + 1-Butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide at 298.15 K and Atmospheric Pressure

Densities, viscosities and refractive indices have been measured at 298.15 K and atmospheric pressure for binary and ternary mixtures of ethanol, ethyl acetate and 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl) imide [C₄mim][NTF₂]. From these experimental properties, the corresponding excess properties have been calculated and adequately fitted with the Redlich-Kister polynomial equation. The adjustable parameters and standard deviations between experimental and calculated values are reported. Interest of this mixture is due to the possibility of using [C₄mim][NTF₂] as an entrainer in the extractive distillation of ethanol + ethyl acetate. These results are compared with previously determined experimental data for mixtures of ethyl acetate and/or ethanol with the ionic liquid 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide, [C₈mim][NTF₂].     

Volumetric and Transport Properties of Ternary Mixtures Containing 1-Butanol or 1-Pentanol,Triethylamine and Cyclohexane at 303.15 K: Experimental Data,Correlation and Prediction by the ERAS Model

The excess molar volumes, V _m^E, viscosity deviations, Δη, and excess Gibbs energies of activation, ΔG ^*E, of viscous flow have been investigated from density and viscosity measurements for two ternary mixtures, 1-butanol + triethylamine + cyclohexane and 1-pentanol + triethylamine + cyclohexane, and corresponding binaries at 303.15 K and atmospheric pressure over the entire range of composition. The empirical equations due to Redlich-Kister, Kohler, Rastogi et al., Jacob-Fitzner, Tsao-Smith, Lark et al., Heric-Brewer, and Singh et al. have been employed to correlate V _m^E, Δη and ΔG ^*E of the ternary mixtures with their corresponding binary parameters. The results are discussed in terms of the molecular interactions between the components of the mixture. Further, the Extended Real Associated Solution, ERAS, model has been applied to V _m^E for the present binary and ternary mixtures, and the results are compared with experimental data.     

Ultrasonic Investigations in Ternary Mixtures Containing Water, 2-Butoxyethanol and <Emphasis Type="Italic">t</Emphasis>-Butanol at 298.15 K

Ultrasonic speeds in, and isentropic compressibilities of, aqueous solutions of water + 2-butoxyethanol (2BE)+t-butanol have been determined at 298.15 K. The concentrations of t-butanol at which the ultrasonic speed becomes maximum and isentropic compressibility becomes minimum are found to decrease with increases in the concentration of 2BE, x _2BE, in the cosolvent (aqueous 2BE). This behavior indicates that the aqueous ternary solutions are less structured than aqueous t-butanol. In the presence of 2-butoxyethanol, enhancement in the hydrogen bonded structure of water due to hydrophobic hydration between t-butanol and water molecules decreases as the concentration of x _2BE in the cosolvent increases. When x _2BE>0.2, the ternary solution behaves like a normal liquid. This behavior is also very well reflected in the concentration dependence of the excess ultrasonic speed and excess isentropic compressibility. The optimum concentrations of t-butanol, ($x_{\mathrm{t}\mbox{-}\mathrm{B}}$x_{\mathrm{t}\mbox{-}\mathrm{B}})_opt, at which extrema in ultrasonic speed, isentropic compressibility, excess ultrasonic speed and excess isentropic compressibility are observed decrease with increase in x _2BE in the cosolvent. The results are explained as being due to a reduction in the strength of hydrophobic interactions responsible for enhancement in the structure of water in aqueous t-butanol in the presence 2BE. Beyond (x_t-Bx_{\mathrm{t}\mbox{-}\mathrm{B}})_opt, the hydrogen bonded network of water collapses and water, 2-butoxyethanol and t-butanol molecules interact with each other as normal liquid molecules.     

Thermodynamics of 1:1 Electrolyte Solutions in Water + N,N-Dimethylformamide Mixed Solvent System at 25°C: Molar Excess Enthalpy of Mixing

The molar excess enthalpies of mixing for the six possible binary combinationsof solutions of NaCl, KCl, NaBr, and KBr as a function of ionic strength fractionhave been measured at 25°C. The experiments were performed at constant ionicstrengths of 1.000 and 2.000 mol-kg^–1 with an LKB flow microcalorimeter inthe mixed solvent water + dimethylformamide. The equations of Friedman'sModel were fitted to the results. Our parameters differ appreciably from thecorresponding results in water and Young's cross square rule does not apply.While Pitzer's ion-interaction model was able to represent the enthalpy data forcommon ion mixings, it was unable to model the data of the noncommon ionmixtures. The data suggests that the problem may arise from variations in solvationof the ions and ion clusters including preferential solvation of certain species.     

Thermodynamic Properties of Binary Liquid Mixtures of n-Dodecane with an Alkan-1-ol or an Alkan-2-ol at 298.15 K: A Comparative Study

Experimental densities (ρ), viscosities (η), and speeds of sound (u) of the binary mixtures of n-dodecane with an alkan-1-ol (hexan-1-ol, heptan-1-ol, octan-1-ol) or an alkan-2-ol (hexan-2-ol, heptan-2-ol and octan-2-ol) were measured over the whole mixture composition range at T = 298.15 K. From these data, the excess molar volume ( $ V_{\text{m}}^{\text{E}} $ V m E ), deviations in viscosity (Δη), and excess isentropic compressibility ( $ \kappa_{S}^{\text{E}} $ κ S E ) have been calculated. The results were fitted by means of the Redlich–Kister equation, in order to estimate the binary coefficients and standard errors. Differences among these binary systems are ascribed to the different association abilities of the alkan-1-ols and alkan-2-ols. Experimental data on the constituted binaries were analyzed using McAllister’s multi-body interaction model, the Jouyban–Acree model, the Prigogine–Flory–Patterson theory, and the Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behavior among the mixtures.     

Densities and Viscosities for Binary and Ternary Mixtures of 2-Methylbutan-2-ol (1) + Trichloroethylene (2) + Acetonitrile (3) at 298.15 K and at Ambient Pressure (81.5 kPa)

Densities (ρ) and viscosities (η) of ternary mixtures of 2-methylbutan-2-ol (1) + trichloroethylene (2) + acetonitrile (3) and the related binary mixtures of {2-methylbutan-2-ol (1) + trichloroethylene (2)}, {2-methylbutan-2-ol (1) + acetonitrile (3)}, and {trichloroethylene (2) + acetonitrile (3)} have been measured over the whole composition range at 298.15 K and at ambient pressure (81.5 kPa). Excess molar volumes $ V_{\text{m}}^{\text{E}} $ , viscosity deviations Δη, and excess Gibbs energies of activation ΔG ^*E were derived from the experimental data. The binary and ternary data of $ V_{\text{m}}^{\text{E}} $ , Δη, and ΔG ^*E for the binary and ternary mixtures were correlated as functions of the mole fraction by using the Redlich–Kister and the Cibulka equations. Kinematic viscosities of the binary mixtures were correlated by means of several semi-empirical equations to determine the fitting parameters and the SDs. The experimental results are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.