Molar volume

Densities (ρ), ultrasonic speeds (u), and excess molar volumes () of binary mixtures of some aromatic ketones in acrylonitrile have been measured over the entire range of composition at 308.15 K. From these experimental results, parameters such as the isentropic compressibilities K S , interaction parameter χ 12, Flory parameters, A i coefficients, standard deviations σ(Y E), and molar sound

This work shows the experimental data of excess properties at several temperatures and the vapor–liquid equilibria (VLE) obtained for four binary systems of alkyl methanoates (methyl to butyl) with decane, all measured at constant pressure of 101.32kPa. The isobaric VLE data were thermodynamically consistent according to the Fredenslund test and did not present an azeotrope. The experimental data of HmE

Apparent molar heat capacities $$C_{{\text{p}},\phi }$$ and volumes $$V_\phi$$ of aqueous trifluoromethanesulfonic (triflic) acid, HCF3SO3 (aq.) were determined with a Picker flow microcalorimeter and vibrating-tube densimeter at temperatures from 283 to 328 K and molalities from 0.05 to 9.5 mol-kg-1. Values of $$V_\phi$$ and $$C_{{\text{p}},\phi }$$ display a maximum near 0.8 mol-kg-1. $$V_\phi$$ also displays a shallow minimum at ~5

Excess molar volumes, \(V_{123}^{\mathrm{E}}\) , of 1,3-dioxolane or 1,4-dioxane (1) + aniline (2) + benzene or toluene (3) ternary mixtures have been determined over the entire mole fraction range at 308.15 K. \(V_{123}^{\mathrm{E}}\) data have been fitted to the Redlich-Kister equation to evaluate ternary adjustable parameters and standard deviations. The observed \(V_{123}^{\mathrm{E}}\) data have been analyzed in terms of (i) Graph theory, (ii) Prigogine-Flory-Patterson theory, and (iii) Sanchez and Lacombe theory. It has been observed that \(V_{123}^{\mathrm{E}}\) values predicted by Graph theory compare well with the corresponding experimental values.

Refractive indexes at 25°C were measured for binary mixtures of tetrahydrofuran with 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol. Densities, from which excess molar volumes were derived, were measured at the same temperature for the system tetrahydrofuran + 1-decanol. Refractive indexes and densities for the pure compounds were determined at 11 temperatures between 20 and 30°C. The thermal expansion coefficients and the temperature derivatives of the refractive index for these liquids were calculated at 25°C. The temperature dependence of the molar refraction was also examined. The contribution to the molar refraction of a CH2 group was calculated as was the difference between contributions from CH3 and CH2OH groups. The change of molar refraction on mixing is d iscussed in terms of molecular interactions and alkyl chain length.

Densities were determined for binary mixtures containing the protic ionic liquid bis(2-hydroxyethyl)ammonium acetate [BHEAA] and an alcohol (methanol, ethanol, and 1-propanol) at four different temperatures (293.15, 303.15, 313.15, and 323.15) K and ambient pressure. Coefficients of thermal expansion and excess molar volumes were calculated from the experimental densities. The excess molar volumes were fitted using the Redlich-Kister polynomial equation. Negative deviations from ideal behavior of the excess molar volume were observed for all systems investigated in this study. The results were interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and alcohol. It was observed that an increase of the alcohol carbon chain length led to lower interactions on mixing.

Resumen Usando el método de solvatación del modelo de apantallamiento tipo conductor (COSMO) y el método de Amovilli-Mennucci contenido en el programa GAMESS, se estimaron las energías libres de Van der Waals y electrostáticas de moléculas orgánicas en su propio medio dieléctrico. Con estas energías y el volumen de la cavidad del soluto, se diseñaron dos modelos de relación estructura-propiedad (QSPR) para determinar el volumen molar y la entalpía de vaporización a la temperatura de ebullición de las moléculas orgánicas. El mejor modelo obtenido usando el volumen molar presenta una correlación igual a 0,9949 y la correlación del modelo usando la entalpía de vaporización fue 0,9895. Palabras clave: Energía libre electrostática; entalpía de vaporización; estructura-propiedad; volumen molar.

The densities ρ, and viscosities η, of pure toluene, cyclohexane, and n-hexane and those of their binary and ternary mixtures have been measured at 298.15 K and atmospheric pressure over the entire range of compositions. Excess molar volumes V123E, viscosity deviations Δη123, and excess Gibbs energy of activation G123*E, were obtained from the experimental results and those values for the binary and ternary systems were fitted to Redlich–Kister's and Cibulka's type function in terms of mole fractions. The V123E data were positive and Δη123 and G123*E, values were negative. Several semi-empirical relations are used to predict the ternary excess molar volumes and viscosity deviations from experimental results on the constituted ternary and analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.