Excess molar enthalpies and excess molar volumes of (1,3-dimethyl-2-imidazolidinone + an aromatic hydrocarbon) atT = 298.15 K

Excess molar enthalpies H_m^Eand excess molar volumesV_m^E of (1,3-dimethyl-2-imidazolidinone  +  benzene, or methylbenzene, or 1,2-dimethylbenzene, or 1,3-dimethylbenzene, or 1,4-dimethylbenzene, or 1,3,5-trimethylbenzene, or ethylbenzene) over the whole range of compositions have been measured at T =  298.15 K. The excess molar enthalpy values were positive for five of the seven systems studied and the excess molar volume values were negative for six of the seven systems studied. The excess enthalpy ranged from a maximum of 435 J · mol ^− 1for (1,3-dimethyl-2-imidazoline  +  1,3,5-trimethylbenzene) to a minimum of  − 308 J · mol ^− 1for (1,3-dimethyl-2-imidazoline  +  benzene). The excess molar volume values ranged from a maximum of 0.95cm³mol ^− 1 for (1,3-dimethyl-2-imidazoline  +  ethylbenzene) and a minimum of  − 1.41 cm³mol ^− 1for (1,3-dimethyl-2-imidazoline  +  methylbenzene). The Redlich–Kister polynomial was used to correlate both the excess molar enthalpy and the excess molar volume data and the NRTL and UNIQUAC models were used to correlate the enthalpy of mixing data. The NRTL equation was found to be more suitable than the UNIQUAC equation for these systems. The results are discussed in terms of the polarizability of the aromatic compound and the effect of methyl substituents on the benzene ring.     

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.     

Excess molar enthalpies and excess molar heat capacities of (2-butanone + cyclohexane,or methylcyclohexane,or benzene,or toluene,or chlorobenzene,or cyclohexanone) atT = 298.15 K

Excess molar enthalpies of (2- butanone  +  cyclohexane, or methylcyclohexane, or toluene, or chlorobenzene, or cyclohexanone) and excess molar heat capacities of (2- butanone  +  benzene, or toluene, or chlorobenzene, or cyclohexanone) were measured atT =  298.15 K. Aliphatic systems were endothermic and the chlorobenzene system was exothermic. On the other hand, the toluene system changed sign to be S-shaped similar to the benzene system reported by Kiyohara et al. The values of excess molar enthalpies of the present mixtures were slightly larger than the corresponding mixtures of cyclohexanone already reported. Excess molar heat capacities of aromatic systems were characteristically S-shaped for the mixture containing aromatics. The values of the present mixtures were less than the corresponding mixtures of cyclohexanone. The mixture (2-butanone  +  cyclohexanone) was endothermic forH_m^E and negative for C_p,m^E.     

(P, Vm, T) Measurements of (octane + 1-chlorohexane) at temperatures from 298.15 K to 328.15 K and at pressures up to 40 MPa

Densities were measured for the liquid octane and 1-chlorohexane, and for nine of their mixtures at four temperatures between 298.15 K and 328.15 K and at pressures up to 40 MPa. An apparatus for density measurements of liquids and liquid mixtures whose main part is a high-pressure vibrating-tube densimeter working in a static mode was used for the measurement. The density data were fitted to the Tait equation and the isothermal compressibilities were calculated with the aid of this equation. Excess molar volumes were also computed from the densities and fitted to the Redlich–Kister equation.     

Excess molar volumes and partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and p = 0.1 MPa

The excess molar volumes and the partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and at atmospheric pressure are reported. The hydrogen bonding between the OH⋯NC groups are discussed in terms of the chain length of the alkanol. The alkanols studied are (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol).The excess molar volume data was fitted to the Redlich–Kister equation The partial molar volumes were calculated from the Redlich–Kister coefficients.     

Excess molar volumes,and excess molar enthalpies of (N-methyl-2-pyrrolidinone + an ether ) at the temperature 298.15 K

Excess molar volumes V_m^E have been calculated from measured density values over the whole composition range at T =  298.15 K and atmospheric pressure for six { N -methyl-2-pyrrolidinone  +  1,1-dimethylethyl methyl ether, or dipropyl ether, or 1,1-dimethylpropyl methyl ether, or diisopropyl ether, or dibutyl ether, or dipentyl ether}. Excess molar enthalpiesH_m^E were also measured for five { N -methyl-2-pyrrolidinone  +  1,1-dimethylethyl methyl ether, or dipropyl ether, or 1,1-dimethylpropyl methyl ether, or diisopropyl ether, or dibutyl ether} at T =  298.15 K and atmospheric pressure. The results are discussed in terms of intermolecular associations. The experimental results have been correlated with the UNIQUAC and NRTL equations.     

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 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.     

Excess molar enthalpies of (methanol + 1-propanol) + oxane or 1,4-dioxane mixtures at the temperature 298.15 K

Experimental excess molar enthalpies H_m^E at the temperature 298.15 K and atmospheric pressure in a flow microcalorimeter are reported for the ternary mixtures: {x₁CH₃OH+x₂C₂H₅OH+(1−x₁−x₂)C₅H₁₀O} and {x₁CH₃OH+x₂C₂H₅OH+(1−x₁−x₂)C₄H₈O₂}. The results have been correlated by means of a polynomial equation and used to construct constant excess enthalpy contours. Further, the results have been compared with those calculated from a UNIQUAC associated-solution model taking into consideration the molecular association of like alcohols, solvation between unlike alcohols and alcohols with oxane (tetrahydropyran) or 1,4-dioxane using only binary information.     

Excess molar volumes and excess molar enthalpies of binary mixtures for 1,2-dichloropropane + 2-alkoxyethanol acetates at 298.15 K

The excess molar volumes and excess molar enthalpies over the whole range of composition have been measured for the binary mixtures formed by 1,2-dichloropropane (1,2-DCP) with three 2-alkoxyethanol acetates at 298.15 K and atmospheric pressure using a digital vibrating-tube densimeter and an isothermal calorimeter with flow-mixing cell, respectively. The 2-alkoxyethanol acetates are ethylene glycol monomethyl ether acetate (EGMEA), ethylene glycol monoethyl ether acetate (EGEEA), and ethylene glycol monobutyl ether acetate (EGBEA). The of the mixture has been shown positive for EGMEA, ‘S-shaped’ for EGEEA, being negative at low and positive at high mole fraction of 1,2-DCP, and negative for EGBEA. All the values for the above mixtures showed an exothermic effect (negative values) which increase with increase in carbon number of the 2-alkoxyethanol acetates, showing minimum values varying from −374 J mol⁻¹ (EGMEA) to −428 J mol⁻¹ (EGBEA) around 0.54–0.56 mol fraction of 1,2-DCP. The experimental results of and were fitted to Redlich–Kister equation to correlate the composition dependence of both excess properties. In this work, the experimental excess enthalpy data have been also correlated using thermodynamic models (Wilson, NRTL, and UNIQUAC) and have been qualitatively discussed.     

Physical properties of (propyl propanoate + hexane + toluene) at 298.15 K

The aim of this paper is to report experimental densities, excess molar enthalpies and refractive indexes of the ternary system (propyl propanoate + hexane + toluene) and of the corresponding binary mixtures (propyl propanoate + toluene) and (hexane + toluene) at the temperature 298.15 K and atmospheric pressure, over the whole composition range. Also, the excess molar volumes and the changes in the refractive index on mixing have been calculated from the measured data for all mixtures.     

Excess molar enthalpies and excess molar volumes of (an alkanol + a nitrile compound) atT = 298.15 K andp = 0.1 MPa

Excess molar enthalpies and excess molar volumes at T =  298.15 K andp =  0.1 MPa are reported for (methanol, or ethanol, or 1-propanol  +  1,4-dicyanobutane, or butanenitrile, or benzonitrile). For all the mixtures investigated in this work the excess molar enthalpy is large and positive. The excess molar enthalpy decreases as the carbon chain number of the alkanol species increases from methanol to propanol. The excess molar volumes are both positive and negative. The Extended Real Associated Solution and the Flory–Benson–Treszczanowicz models were used to represent the data. Both these models describe better the excess molar enthalpy than the excess molar volumes of (an alkanol  +  a nitrile compound).     

Excess molar enthalpies for (benzonitrile + an aromatic hydrocarbon) atT = 298.15 K

The excess molar enthalpies of (benzonitrile  +  benzene, or methylbenzene, or 1,2-dimethylbenzene, or 1,3-dimethylbenzene, or 1,4-dimethylbenzene, or 1,3,5-trimethylbenzene, or ethylbenzene) have been determined at T =  298.15 K. The excess molar enthalpies range from  − 10 J · mol ^− 1for methylbenzene to 130 J · mol ^− 1for 1,3,5-trimethylbenzene. The Redlich–Kister equation, the NRTL, and UNIQUAC models were used to correlate the data. The results indicate a relatively strong association between benzonitrile and each of the aromatic compounds, decreasing with increasing methyl substitution on the benzene moiety.