Thermodynamics of mixtures with strongly negative deviations from Raoult's law. XVII. Permittivities and refractive indices for alkan-1-ol + N,N-diethylethanamine systems at (293.15-303.15) K. Application of the Kirkwood-Fröhlich model

Abstract

Relative permittivities at 1 MHz, ${\epsilon }_{\text{r}}$, at 0.1 MPa and (293.15-303.15) K and refractive indices, $n_{\text{D}}$, at similar conditions have been measured for the alkan-1-ol (methanol, propan-1-ol, butan-1-ol, pentan-1-ol or heptan-1-ol) + N,N-diethylethanamine (TEA) systems. Positive values of the excess permittivities, ${\epsilon }_{\text{r}}^{\text{E}}$ , are encountered for the methanol system at high alcohol concentrations. The remaining mixtures are characterized by negative ${\epsilon }_{\text{r}}^{\text{E}}$ values over the whole composition range. At ${\varphi }_1$ (volume fraction) = 0.5, ${\epsilon }_{\text{r}}^{\text{E}}$ changes in the order: methanol > propan-1-ol > butan-1-ol < pentan-1-ol < heptan-1-ol. Mixtures formed by alkan-1-ol and an isomeric amine, hexan-1-amine (HxA) or N-propylpropan-1-amine (DPA) or cyclohexylamine, behave similarly. This has been explained in terms of the lower and weaker self-association of longer alkan-1-ols. From the permittivity data, it is shown that: (i) (alkan-1-ol)-TEA interactions contribute positively to ${\epsilon }_{\text{r}}^{\text{E}}$; (ii) TEA is an effective breaker of the network of the alkan-1-ols; (iii) structural effects, which are very important for the volumetric and calorimetric data of alkan-1-ol + TEA systems, are also relevant when evaluating dielectric data. This is confirmed by the comparison of ${\epsilon }_{\text{r}}^{\text{E}}$ measurements for alkan-1-ol + aliphatic amine mixtures; (iv) the aromaticity effect (i.e., the replacement of TEA by pyridine in systems with a given alkan-1-ol) leads to an increase of the mixture polarization. Calculations conducted in the framework of the Kirkwood-Fröhlich model are consistent with the previous statements.

arXiv admin note: text overlap with arXiv:2409.11801, arXiv:2409.17926

References in corpus (3)

• Dielectric and refractive index measurements for the systems 1-pentanol + octane, or + dibutyl ether or for dibutyl ether + octane at different temperatures
• Thermodynamics of mixtures with strongly negative deviations from Raoult's law. XVI. Permittivities and refractive indices for 1-alkanol + di-n-propylamine systems at (293.15-303.15) K. Application of the Kirkwood-Fröhlich model
• Thermodynamics of mixtures with strongly negative deviations from Raoult's law. XV. Permittivities and refractive indices for 1-alkanol + n-hexylamine systems at (293.15-303.15) K. Application of the Kirkwood-Fröhlich model

Cited by in corpus (4)

• Density, speed of sound, refractive index and relative permittivity of methanol, propan-1-ol or pentan-1-ol + aniline liquid mixtures. Application of the Kirkwood-Fröhlich model
• Thermodynamics of mixtures with strong negative deviations from Raoult's law. XVIII: Excess molar enthalpies for the (1-alkanol + cyclohexylamine) systems at 298.15 K and modelling
• Density, speed of sound, refractive index and relative permittivity of methanol, propan-1-ol or pentan-1-ol + benzylamine liquid mixtures. Application of the Kirkwood-Fröhlich model
• Thermodynamics of mixtures containing amines. XVII. Excess molar enthalpy and volume measurements for benzylamine + heptane or + 1-alkanol mixtures at 298.15 K. Application of the DISQUAC and ERAS models