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

Abstract Relative permittivities at 1 MHz, e r , and refractive indices at the sodium D-line, n D , are reported at 0.1 MPa and at (293.15–303.15) K for the binary systems 1-alkanol +  n -hexylamine (HxA). Also, their corresponding excess functions are calculated and correlated. Positive values of the excess permittivities, e r E , are encountered for the methanol system, whereas the remaining mixtures show negative values. This reveals that interactions between unlike molecules contribute positively to e r E . This contribution is dominant for the methanol mixture, while those arising from the breaking of interactions between like molecules are prevalent for the remaining mixtures. At φ 1 (volume fraction) = 0.5, e r E changes in the order: methanol > 1-propanol > 1-butanol > 1-pentanol