J. Ortega

Analysis of thermodynamic properties of 1-alkanol + n-alkane mixtures using the nitta—chao group contribution model

Abstract In 1977, Nitta et al. published a group contribution molecular model for thermodynamic properties of polar and non-polar liquids and their solutions, including energy of vaporization, pVT relationships, excess properties and activity coefficients. At the same time they reported the corresponding characteristic parameters for methyl, methylene, hydroxyl and carbonyl groups and for their mutual interactions. Since the values predicted by the Nitta et al. model for certain excess properties of alcohol + alkane systems using these parameters differ significantly from experimental findings, we have recalculated the relevant parameters using data for a larger number of mixtures and for properties such as excess volumes that were not included in the original database.

Excess molar volumes of (ethyl formate or ethyl acetate + an isomer of hexanol) at 298.15 K

Excess molar volumes VmE were determined over the entire composition range at 298.15 K for ethyl formate or ethyl acetate + hexan-1-ol, +2-methylpentan-1-ol, +3-methylpentan-2-ol, +2-methylpentan-3-ol, +3-methylpentan-3-ol, +2-methylpentan-2-ol, +4-methyl-pentan-2-ol, and +hexan-2-ol. Excess volumes were determined from density measurements made with a vibrating-tube densimeter. The VmE values were all positive, decreasing with the n value of the ester: Cn−1H2n−1CO2C2H5.

Analysis of excess enthalpies of ethyl formate + n-alkane or 1-alkanol with two group contribution models

Abstract We present experimental values of enthalpies of mixing at 298.15 K for mixtures composed of ethyl formate with n-alkanes (from n-hexane to n-decane) or 1-alkanols (from 1-propanol to 1-decanol). Then hE data for the latter mixtures have been used to determine characteristic formate-alkanol interaction parameters for three group contribution models: the UNIFAC model with and without consideration of 1-alkanol association effects, and the Nitta-Chao model. The experimental data are reproduced within mean errors of less than 6% by all the used models.

Excess enthalpies of five examples of (2-hexanone + an n-alkane) and five of (2-hexanone + an n-alkanol) at 298.15 K

Abstract Excess molar enthalpies H m E have been measured as a function of the mole fraction x at 298.15 K and atmospheric pressure for the 10 mixtures: {x CH 3 COC 4 H 9 + (1−x) C n H 2n+2 }, (n = 6, 7, 8, 9, and 10) ; {x CH 3 COC 4 H 9 + (1−x) C n H 2n+1 OH }, (n = 6, 7, 8, 9, and 10) . Measurements were carried out using a Calvet microcalorimeter, and variable-degree polynomials have been fitted to the results.

Excess molar volumes of (ethyl formate + each of several alkanols) at 298.15 K

Abstract The excess molar volumes at 298.15 K of 10 examples of { x HCO 2 C 2 H 5 + (1 − x )C n H 2 n + 1 OH} (1 ⩽ n ⩽ 10) have been obtained for 0 ⩽ x ⩽ 1 from densities measured with a vibrating-tube densimeter. All the excess molar volumes are positive except these of { x HCO 2 C 2 H 5 + (1 − x )CH 3 OH}. Variable-degree polynomials have been fitted to the experimental results.

Excess volumes of (toluene + each of several isomers of hexanol) at 298.15 K

Abstract The excess molar volumes V m E of (toluene + each of several isomers of hexanol) have been determined at 298.15 K over the whole range of mole fraction x using a vibrating-tube digital densimeter. All the excess molar volumes are positive except those of x {C 6 H 5 CH 3 + (1 − x )C 6 H 13 OH}, which are negative for x