J. Canosa

Mixing properties of (methanol, ethanol, or 1-propanol) with (n-pentane, n-hexane, n-heptane and n-octane) at 298.15 K

In this work, we present experimental values of the density, refractive index, speed of sound, and dynamic viscosity of the binary mixtures (methanol, ethanol or 1-propanol) with (n-pentane, n-hexane, n-heptane, and n-octane) at 298.15 K and atmospheric pressure, as a function of the molar fraction. From the experimental values, the corresponding excess and deviation values were computed (excess molar volumes, changes of refractive index on mixing, changes of isentropic compressibility and dynamic viscosity deviations), variable-degree polynomials being fitted to the results. Different methods were applied in order to estimate values of these physical properties, in good agreement with experiment. The binodal tie lines for each methanol + alkane binary mixture at different temperatures were determined by the measurement of physical properties and application of the corresponding fitting polynomials. UNIFAC-Dortmund group contribution method was applied to predict these liquid-liquid equilibria.

HMImPF6 ionic liquid that separates the azeotropic mixture ethanol + heptane

1-Hexyl-3-methylimidazolium hexafluorophosphate (HMImPF6) is suitable for use as the solvent in the petrochemical extraction process for the removal of heptane from its azeotropic mixture with ethanol. The experimental determination of the liquid–liquid equilibrium (LLE) for the ternary system heptane + ethanol + HMImPF6 at 298.15 K was carried out. The solute distribution ratio and the selectivity of the HMImPF6 have been determined from the tie-line data. A comparative study has been made in terms of selectivity and solute distribution data with other ionic liquids. The NRTL equation was verified to accurately correlate the experimental data.

Binary mixture properties of diethyl ether with alcohols and alkanes from 288.15 K to 298.15 K

Abstract Density, refractive index and speed of sound of the binary mixtures (diethyl ether+methanol, or ethanol, or n-hexane, or n-heptane) from 288.15 K to 298.15 K and atmospheric pressure, have been measured over the whole composition range. Excess molar volumes, changes of refractive index on mixing and excess isentropic compressibilities for the binary systems were calculated and fitted to Redlich–Kisters equation to estimate the fitting parameters and the root mean square deviations between calculated and experimental data. Values of density and refractive index were evaluated and compared by different methods. Excess partial molar volumes and those corresponding to the infinite dilution condition are also calculated.

Thermodynamic behaviour of mixtures containing methyl acetate, methanol, and 1-butanol at 298.15 K: application of the ERAS model

Abstract Excess molar volumes, and changes of refractive indices, of the ternary mixture methyl acetate+methanol+1-butanol, and the binary mixtures methyl acetate+1-butanol, and methanol+1-butanol have been evaluated from density, and refractive indices measurements at 298.15 K, and 1 atm. These derived properties of binary, and ternary mixtures were fitted to Redlich–Kister, and Cibulka type equations, respectively. The ERAS model interaction parameters of the binary systems contained in the ternary mixture were computed, the obtained results showing good accuracy. The high polar/associative behaviour of the mixtures should be the cause of high deviations in ternary excess prediction. The obtained results suggest the convenience of extending the model to multicomponent polar/associative mixtures in order to take into account all binary polar effects, and higher order polar effects in the mixtures.

Thermodynamic properties of alkanediols+ acetates at 298.15 K

In this work we present experimental values of the density, refractive index, speed of sound, isentropic compressibility and liquid-liquid equilibria of the binary mixtures (methyl acetate, ethyl acetate, propyl acetate, and butyl acetate) with (1,2-ethanediol, 1,2-propanediol, or 1,3-propanediol) at 298.15 K and atmospheric pressure, as a function of mole fraction. From the experimental values, the corresponding excess and deviation values were computed (excess molar volumes, changes of refractive index on mixing, and changes of isentropic compressibility), variable-degree polynomials being fitted to the results. The validity of different estimation methods for predicting the experimental values of physical properties was tested. The limiting partial excess molar volume of the components in each binary mixture was determined by means of predetermined Redlich-Kister parameters. Group contribution method (UNIFAC-Dortmund) was applied in order to compare their capability in predicting the experimental equilibria values.