Binary Mixtures of 2-Ethyl-1-hexanol and 1, 2-Disubstituted Ethanes: Thermophysical, Ultraacoustic and Computational Studies

Densities (\(\rho\)) and viscosities (\(\eta\)) of the binary mixtures of 2-ethyl-1-hexanol (2-EH) with ethylenediamine, 1,2-dichloroethane (DCE) and monoethanolamine (MEA) were measured at T = (298.15–318.15) K under atmospheric pressure over the entire composition range (\(x_{{1}} = 0 - 1.0\)). For these binary mixtures ultrasonic speeds (\(u\)) and refractive indices (\(n_{{\text{D}}}\)) were also measured at 298.15 K. With these experimental data the excess molar volumes (\(V_{{\text{m}}}^{{\text{E}}}\)), viscosity deviations (\(\Delta \eta\)), excess molar refractions (\(R_{{\text{m}}}^{{\text{E}}}\)), excess isentropic compressibility (\(\kappa_{{\text{S}}}^{{\text{E}}}\)) and other derived properties were determined at various experimental temperatures. Such thermophysical properties were discussed in terms of molecular interactions and structural effects well corroborated with IR spectra of the mixtures. Excess molar volumes (\(V_{{\text{m}}}^{{\text{E}}}\)) of the binary mixtures were used to derive partial molar volumes (\(\overline{V}_{{\text{m,1}}}^{{0}}\) and \(\overline{V}_{{{\text{m,}}\,{\kern 1pt} {2}}}^{{0}}\)) and excess partial molar volumes (\(\overline{V}_{{\text{m,1}}}^{{\text{0,E}}}\) and \(\overline{V}_{{\text{m,2}}}^{{\text{0,E}}}\)) at infinite dilution to reveal the volume changes of the binary mixtures. Prigogine-Flory-Paterson theory (PFP), Peng-Robinson Equation of States (PR-EOS) and Bloomfield-Dewan (BF-D) model were used to predict excess molar volumes (\(V_{{\text{m}}}^{{\text{E}}}\)) and viscosities (\(\eta\)) of the mixtures. Ultrasonic speeds (\(u\)) of the binary mixtures predicted using empirical or semi-empirical theories like free length theory, Impedance dependence relation, Ideal mixture relation, Junjie’s relation, collision factor theory and Nomoto’s relation, etc. Computational studies have also been performed to establish the degree and nature of solvent–solvent interactions theoretically.