Dielectric and refractive index measurements for the systems 1-pentanol + octane, or + dibutyl ether or for dibutyl ether + octane at different temperatures

• Published in: Thermochimica acta Vol. 543; pp. 246 - 253
• Main Authors: Alonso, Víctor, González, Juan Antonio, García de la Fuente, Isaías, Cobos, José Carlos
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 10-09-2012; Elsevier
• Subjects: 1-Pentanol; calorimetry; Chemical thermodynamics; Chemistry; Correlation factor; Cyclic species; equations; Exact sciences and technology; General and physical chemistry; General. Theory; octane; pentanols; Permittivity; Refractive index; temperature; Cyclic species; Correlation factor; Permittivity; Refractive index; 1-Pentanol
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2012.05.036

▸ ɛr(T), nD(T) data for 1-pentanol + octane, +dibutylether, and dibutylether + octane are given. ▸ Correlation factors, gk, at 298.15 K are calculated from Kirkwood–Fröhlich equations. ▸ The ether is more active than octane when breaking alkanol self-association. ▸ This is supported by values of molar polarization, ɛr(T) and of gk.
Relative permittivities, ɛr and refractive indices, nD, have been measured at (288.15–308.15) K and (293.15–303.15) K, respectively, for the mixtures 1-pentanol + octane, or + dibutyl ether and dibutyl ether + octane. These data have been used, together with density measurements available in the literature, to determine the correlation factor, gk, for the studied systems according to the Kirkwood–Fröhlich equations. Results show that the existence of cyclic species of 1-pentanol is predominant at low concentrations of this alkanol when is mixed with octane. These species are broken in large extent by the more active molecules of oxaalkane in the dibutyl ether mixture, which is in agreement with calorimetric data. The dibutyl ether + octane system does not show meaningful structure. These conclusions are confirmed by values of the molar polarization and by the temperature dependence of ɛr. The empirical expressions of Lorentz–Lorenz, Wiener, Heller, Gladstone–Dale and Newton correlate well the nD data.