Excess enthalpies of the ternary mixtures: tetrahydrofuran + (diisopropyl ether or 2-methyltetrahydrofuran) + n-heptane at 298.15 K

Excess molar enthalpies, measured at 298.15 K in a flow microcalorimeter, are reported for the ternary mixtures (tetrahydrofuran + diisopropyl ether + n-heptane) and (tetrahydrofuran + 2-methyltetrahydrofuran + n-heptane). Smooth representations of the results are described and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The latter are compared with diagrams obtained when the model of Liebermann and Fried is used to estimate the excess enthalpies of the ternary mixtures from the physical properties of the components and their binary mixtures.     

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 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.     

Application of the principle of congruence to ternary alkane mixtures

Excess enthalpies and excess volumes at 298.15 K and atmospheric pressure have been measured for mixtures of n-hexane + (an equimolar mixture of n-tridecane + n-nonadecane). The agreement of the results with the corresponding results for mixtures of n-hexane + n-hexadecane is interpreted as confirmation of the applicability of the principle of congruence to multicomponent mixtures.     

Molar excess volumes and molar excess enthalpies of methylenebromide + aromatic hydrocarbon mixtures

Molar excess volumes V^e and molar excess enthalpies H^e of binary methylenebromide (i) +benzene. +toluene, and + o^?, + m^? and + p-xylene (j) mixtures have been determined at 298.15 and 308.15 K. The data have been analysed in terms of recent approaches for solutions of nonelectrolytes, and the results suggest that these mixtures are characterised by specific interactions between the components. Self-volume interaction coefficients V_iiV_jj have also been evaluated.     

Excess enthalpies of ketone+methyl methylthiomethyl sulfoxide or +dimethyl sulfoxide at 298.15 k

Excess enthalpies of sixteen binary mixtures between one each of methyl methylthiomethyl sulfoxide (MMTSO) and dimethyl sulfoxide (DMSO) and one of ketone {CH₃CO(CH₂)_nCH₃, n=0 to 6 and CH₃COC₆H₅} have been determined at 298.15 K. All the mixtures showed positive excess enthalpies over the whole range of mole fractions. Excess enthalpies of ketone+MMTSO or DMSO increased with increasing the number of methylene radicals in the methyl alkyl ketone molecules. Excess enthalpies of MMTSO+ketone are smaller than those of DMSO+ketone for the same ketone mixtures. The limiting excess partial molar enthalpies of the ketone, H ₁ ^E,∞, in all the mixtures with MMTSO were smaller than those of DMSO. Linear relationships were obtained between limiting excess partial molar enthalpies and the number of methylene groups except 2-propanone.     

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.     

Thermodynamic properties of binary mixtures containing aldehydes. II. Liquid-vapor equilibria in normal or branched alkanal + normal alkane mixtures: Analysis in terms of a quasichemical group-contribution model

Recent liquid-vapor equilibrium data for three alkanal + n-alkane mixtures are examined on the basis of the surface-interaction version of the quasichemical group-contribution theory used in Part I to correlate and predict excess enthalpies and excess Gibbs energies for such mixtures. The predictions prove to be accurate to better than 10%. Using the new data, revised interaction parameters are proposed for the estimation of liquid-vapor equilibrium for normal or branched alkanal + normal alkane mixtures.     

Excess molar enthalpies of triethylamine + ethylbenzene, + n-propylbenzene, + n-butylbenzene, + isopropylbenzene,and + isobutylbenzene at 303.15 K

Excess molar enthalpies H_m^E of triethylamine + ethylbenzene, + n-propylbenzene, + n-butylbenzene, + isopropylbenzene, and + isobutylbenzene were measured over the entire composition range at 303.15 K with an LKB flow microcalorimeter. H_m^E values are positive and decrease with increasing chain length of the alkylbenzene.     

Excess volumes for n-alkanols + n-alkanes I. Binary mixtures of methanol,ethanol, n-propanol,and n-butanol + n-heptane

Excess volumes V^E measured at 298.15 K in a successive-dilution dilatometer are reported for binary mixtures of the n-alkanols C₁ to C₄ + n-heptane. For ethanol +, and n-butanol + n-heptane, the measurements were extended to high dilutions of alkanol. V^E is positive for all of the mixtures but decreases rapidly in magnitude for increasing chain length of the n-alkanol. The results were used to estimate the excess partial molar volumes of the components.     

Excess enthalpies of alkane-1-amines {CnH2n+1NH2, n = 3-8} + methyl methylthiomethyl sulfoxide and +dimethyl sulfoxide at 298.15 K

Excess enthalpies of binary mixtures between each of alkane-1-amines {C_nH_2n+1NH₂, n=3-8} and methyl methylthiomethyl sulfoxide (MMTSO) or dimethyl sulfoxide (DMSO) have been determined at 298.15 K. All mixtures showed positive enthalpy changes over the whole range of mole fractions.The limiting excess partial molar enthalpies of the aliphatic amines, H₁^E,∞, of all the mixtures with MMTSO or DMSO studied were smaller than those of MMTSO or DMSO, H₂^E,∞, respectively. Linear relations are obtained between limiting excess partial molar enthalpies and number of methylene groups.     

Ternary excess molar enthalpies for the mixtures of methanol and ethanol with tetrahydropyran or 1,4-dioxane at 298.15 K

Ternary excess molar enthalpies, H_m^E, at 298.15 K and atmospheric pressure measured by using a flow microcalorimeter are reported for the (methanol+ethanol+tetrahydropyran) and (methanol+ethanol+1,4-dioxane) mixtures. The pseudobinary excess molar enthalpies for all the systems are found to be positive over the entire range of compositions. The experimental results are correlated with a polynomial equation to estimate the coefficients and standard errors. The results have been compared with those calculated from a UNIQUAC associated solution model in terms of the self-association of alcohols as well as solvation between unlike alcohols and alcohols with tetrahydropyran or 1,4-dioxane. The association constants, solvation constants and optimally fitted binary parameters obtained solely from the pertinent binary correlation predict the ternary excess molar enthalpies with an excellent accuracy.     

Excess molar enthalpies of (methylcyclohexane+an alkanol) at 323.15 K I. Results for n-butanol,n-pentanol,and n-hexanol

Calorimetric measurements of excess molar enthalpies are reported for (methylcyclohexane + n-butanol or n-pentanol or n-hexanol) at 323.15 K. To each set of results variable-degree polynomials were fitted by the least-squares method.     

Molar excess enthalpies of cis-decalin + benzene, + toluene, +isooctane and +heptane at 298.15 K

Molar excess enthalpies H^E of cis-decalin + benzene, +toluene, +isooctane and +heptane mixtures have been measured by an LKB flow microcalorimeter at 298.15 K. The experimental results are analyzed using the Flory-Patterson-Prigogine theory. The isomer effect of decalin molecule and the effect of the molecular size and shape of the component molecules are discussed.     

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.