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.     

Thermodynamic excess properties for binary mixtures of (butanenitrile + a carboxylic acid) atT = 298.15 K

Excess molar enthalpies and excess molar volumes for (butanenitrile  +  acetic acid, or propanoic acid, or butanoic acid, or 2-methylpropanoic acid, or pentanoic acid, or 3-me thylbutanoic acid) atT =  298.15 K are presented. The excess molar enthalpy values are found to be positive for all six systems, whereas the excess molar volumes are found to be negative. The excess molar enthalpy values are correlated by the UNIQUAC and NRTL models and also by the Redlich–Kister polynomial.     

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.     

Application of the PFV EoS correlation to excess molar volumes of (1-ethyl-3-methylimidazolium ethylsulfate + alkanols) at different temperatures

The experimental densities for the binary systems of an ionic liquid and an alkanol {1-ethyl-3-methylimidazolium ethylsulfate [EMIM]⁺ [EtSO₄]^? + methanol or 1-propanol or 2-propanol} were determined at T = (298.15, 303.15, and 313.15) K. The excess molar volumes for the above systems were then calculated from the experimental density values for each temperature. The Redlich–Kister smoothing polynomial was used to fit the experimental results and the partial molar volumes were determined from the Redlich–Kister coefficients. For all the systems studied, the excess molar volume results were negative over the entire composition range for all the temperatures. The excess molar volumes were correlated with the pentic four parameter virial (PFV) equation of state (EoS) model.     

Excess molar volumes and isentropic compressibility of binary systems {trioctylmethylammonium bis(trifluoromethysulfonyl)imide + methanol or ethanol or 1-propanol} at different temperatures

This paper reports measurements of densities for the binary systems of an ionic liquid and an alkanol at T = (298.15, 303.15, and 313.15) K. The IL is trioctylmethylammonium bis(trifluoromethylsulfonyl)imide [OMA]⁺[Tf₂N]^? and the alkanols are methanol, or ethanol, or 1-propanol. The speed of sound at T = 298.15 K for the same binary systems was also measured. The excess molar volumes and the isentropic compressibilities for the above systems were then calculated from the experimental densities and the speed of sound, respectively. Redlich–Kister smoothing polynomial equation was used to fit the excess molar volume and the deviation in isentropic compressibility data. The partial molar volumes were determined from the Redlich–Kister coefficients. For all the systems studied, the excess molar volumes have both negative and positive values, while the deviations in isentropic compressibility are negative over the entire composition range.     

Excess molar enthalpies of binary systems containing 2-octanone,hexanoic acid,or octanoic acid at T = 298.15 K

An isothermal titration calorimeter was used to measure the excess molar enthalpies (H^E) of six binary systems at T = 298.15 K under atmospheric pressure. The systems investigated include (1-hexanol + 2-octanone), (1-octanol + 2-octanone), (1-hexanol + octanoic acid), (1-hexanol + hexanoic acid), {N,N-dimethylformamide (DMF) + hexanoic acid}, and {dimethyl sulfoxide (DMSO) + hexanoic acid}. The values of excess molar enthalpies are all positive except for the DMSO- and the DMF-containing systems. In the 1-hexanol with hexanoic acid or octanoic acid systems, the maximum values of H^E are located around the mole fraction of 0.4 of 1-hexanol, but the H^E vary nearly symmetrically with composition for other four systems. In addition to the modified Redlich–Kister and the NRTL models, the Peng–Robinson (PR) and the Patel–Teja (PT) equations of state were used to correlate the excess molar enthalpy data. The modified Redlich–Kister equation correlates the H^E data to within about experimental uncertainty. The calculated results from the PR and the PT are comparable. It is indicated that the overall average absolute relative deviations (AARD) of the excess enthalpy calculations are reduced from 18.8% and 18.8% to 6.6% and 7.0%, respectively, as the second adjustable binary interaction parameter, k_bij, is added in the PR and the PT equations. Also, the NRTL model correlates the H^E data to an overall AARD of 10.8% by using two adjustable model parameters.     

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.     

Excess molar volumes and viscosities of (1,1,2,2-tetrabromoethane + 1-alkanols) at T = (293.15 and 303.15) K

Density and viscosity measurements for binary mixtures of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-hexanol, or + 1-heptanol, or + 1-octanol, or + 1-decanol) at T = (293.15 and 303.15) K, have been conducted at atmospheric pressure. The excess molar volumes V^E, have been calculated from the experimental measurements, and the results were fitted to Redlich–Kister equation. The viscosity data were correlated with the model of Grunberg and Nissan, and McAllister four-body model. The excess molar volumes of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-haxanol, or + 1-heptanol, or + 1-octanol) had a sigmoidal shape and the values varied from negative to positive with the increase in the molar fraction of 1,1,2,2-tetrabromoethane. The remaining binary mixture of (1,1,2,2-tetrabromoethane + 1-decanol) was positive over the entire composition range. The effects of the 1-alkanol chain length as well as the temperature on the excess molar volume have been studied. The results have been qualitatively used to explain the molecular interaction between the components of these mixtures.     

Volumetric properties and enthalpies of solution of alcohols CkH2k+1OH (k = 1, 2, 6) in 1-methyl-3-alkylimidazolium bis(trifluoromethylsulfonyl)imide {[C1CnIm][NTf2] n = 2, 4, 6, 8, 10} ionic liquids

We present a study on the effect of the alkyl chain length of the imidazolium ring in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids, [C₁C_nIm][NTf₂] (n = 2 to 10), on the mixing properties of (ionic liquid + alcohol) mixtures (enthalpy and volume). We have measured small excess molar volumes with highly asymmetric curves as a function of mole fraction composition (S-shape) with more negative values in the alcohol-rich regions. The excess molar volumes increase with the increase of the alkyl-chain length of the imidazolium cation of the ionic liquid. The values of the partial molar excess enthalpy and the enthalpy of mixing are positive and, for the case of methanol, do not vary monotonously with the length of the alkyl side-chain of the cation on the ionic liquid – increasing from n = 2 to 6 and then decreasing from n = 8. This non-monotonous variation is explained by a more favourable interaction of methanol with the cation head group of the ionic liquid for alkyl chains longer than eight carbon atoms. It is also observed that the mixing is less favourable for the smaller alcohols, the enthalpy of mixing decreasing to less positive values as the alkyl chain of the alcohol increases. Based on the data from this work and on the knowledge of the vapour pressure of {[C₁C_nIm][NTf₂] + alcohol} binary mixtures at T = 298 K reported in the literature, the excess Gibbs free energy, excess enthalpy and excess entropy could be then calculated and it was observed that these mixtures behave like the ones constituted by a non-associating and a non-polar component, with its solution behaviour being determined by the enthalpy.     

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.     

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.     

Excess molar enthalpies of (acetonitrile + butan-2-one) and (methanol + acetonitrile + butan-2-one) atT = 298.15 K

The excess molar enthalpies of (acetonitrile  +  butan-2-one) and (methanol  +  acetonitrile  +  butan-2-one) were measured atT =  298.15 K and atmospheric pressure using a flow microcalorimeter. The experimental results are correlated with polynomial equations and compared with those calculated from associated solution models taking account into self-association of methanol and acetonitrile as well as solvation between unlike molecules and a non-polar interaction term.     

Excess molar enthalpies of {diethyl oxalate + (methanol, + ethanol, + 1-propanol,and + 2-propanol)} at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa

A flow-mixing isothermal microcalorimeter was used to measure excess molar enthalpies for four binary systems of {diethyl oxalate + (methanol, + ethanol, + 1-propanol, and + 2-propanol)} at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa. The densities of the diethyl oxalate at different temperature were measured by using a vibrating-tube densimeter. All systems exhibit endothermic behaviour over the whole composition range, which means that the rupture of interactions is energetically the main effect. The excess molar enthalpies increase with temperature and the molecular size of the alcohols. The experimental results were correlated by using the Redlich–Kister equation and two local-composition models (NRTL and UNIQUAC).     

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 enthalpies for mixtures of acrylonitrile and an aromatic hydrocarbon at T = 298.15 K and p = 101325 Pa

Excess molar enthalpies for (acrylonitrile  +  benzene, or methylbenzene, or 1,2-dimethylbenzene, or 1,3-dimethylbenzene, or 1,4-dimethylbenzene, or 1,3,5-trimethylbenzene, or ethylbenzene) atT =  298.15 K and p =  101325 Pa are presented. The excess molar enthalpy range from 531J · mol ^− 1at x =  0.5 for 1,3,5-trimethylbenzene to 210J · mol ^− 1at x =  0.5 for toluene. The Redlich–Kister equation, the NRTL and UNIQUAC models were used to correlate the data.     

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.     

Density,refractive index on mixing,and speed of sound of the ternary mixtures (dimethyl carbonate or diethyl carbonate + methanol + toluene) and the corresponding binaries atT = 298.15 K

The density, refractive index on mixing, and speed of sound at T =  298.15 K and atmospheric pressure have been measured over the whole composition range for {dimethyl carbonate (DMC), or diethyl carbonate (DEC)  +  methanol  +  toluene}, (diethyl carbonate  +  methanol), (dimethyl carbonate, or diethyl carbonate  +  toluene), and (methanol  +  toluene). Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems have been calculated. Redlich–Kister and Cibulka equations have been used to estimate the binary and ternary fitting parameters and standard deviations from the regression lines are shown. Values of derived and excess properties were estimated and compared by different methods.     

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.     

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.     

Densities,refractive indices,and derived properties of (cyclohexane,orn-heptane + an aromatic hydrocarbon) atT = 298.15 K

This paper reports experimental densities and refractive indices of (cyclohexane, or n -heptane  + o -xylene, or m -xylene, or p -xylene, or ethylbenzene) over the whole composition range at T =  298.15 K and at atmospheric pressure. Excess molar volumes and changes of refractive indices were calculated from the experimental data obtained. Partial excess molar volumes were also computed for all the mixtures studied. The results were fitted by means of the Redlich–Kister equation with the aid of F -test to optimize the number of parameters. Measurements were compared with other literature values. Different empirical and semiempirical models were applied in order to estimate physical property values and good agreement was obtained with experimental results.