Studies on the importance of chain length of alkanols on the thermodynamic and transport properties of liquid mixtures at various temperatures

Abstract

Densities (ρ), speeds of sound (u), and viscosities (η) are reported for binary mixtures of N,N-diethyl aniline with higher 1-alkanols (1-octanol, 1-nonanol and 1-decanol) over the entire composition range of mole fraction at T=(303.15–318.15) K and at atmospheric pressure 0.1MPa. The excess properties such as excess molar volume, excess isentropic compressibility and deviation in viscosity are calculated from the experimental density, speed of sound and viscosity. Excess properties are correlated using the Redlich–Kister polynomial smoothing equation. The excess partial molar volumes and excess partial molar isentropic compressibilities are calculated for all the binary systems throughout the composition range and also at infinite dilutions. The results are analysed in terms of rupture of hydrogen bonded chain of the dipolar interaction between solute and alkan-1-ol exceeds the intermolecular interaction through dipole-dipole and hydrogen bonding between N,N-diethyl aniline and 1-alkanol molecules. The VE results are analysed in the light of Prigogine-Flory-Patterson theory. Analysis of each of the three contributions viz. interactional, free volume and P∗ to VE has shown that interactional contribution are positive for all systems, the free volume effect are negative for all the mixtures and P∗ contribution are positive for all the mixtures except 1-octanol which has a negative internal pressure. The variations of these parameters with composition and temperature discussed in terms of intermolecular interactions prevailing in these mixtures.