Thermophysical\nProperties and Molecular Interactions\nin Binary Mixtures of Oxolane with 2‑Alkoxyethanols

Densities (ρ), viscosities (η), and refractive\nindices\n(<i>n</i><sub>D</sub>) have been measured for binary mixtures\nof oxolane (tetrahydrofuran, THF) with 2-alkoxyethanols (2-ethoxyethanol,\nEE; 2-butoxyethanol, BE) over the entire composition range and at\ntemperatures from 298.15 to 323.15 K in 5 K increments. From these\ndata, excess molar volume (<i>V</i><sub>m</sub><sup>E</sup>), thermal expansivity (α), excess thermal expansivity (α<sup>E</sup>), deviation in viscosity (Δη), free energy for\nthe activation of viscous flow (Δ<i>G</i><sup>≠</sup>) and its excess (Δ<i>G</i><sup>≠E</sup>),\nand deviation in refractive index (Δ<i>n</i><sub>D</sub>) were calculated. The variations in these properties with the composition\nand temperature indicate that cross-hydrogen bonding, chain length\neffects, and molecular packing play significant roles in both EE +\nTHF and BE + THF systems. The measured ρ, η, and <i>n</i><sub>D</sub> data were fitted to concentration-dependent\npolynomial equations, while excess properties (<i>V</i><sub>m</sub><sup>E</sup>, Δη, Δ<i>G</i><sup>≠E</sup>, and Δ<i>n</i><sub>D</sub>) were\nfitted to Redlich–Kister-type equations. Densities were additionally\ncorrelated using the Jouyban-Acree model. The correlating abilities\nof various viscosity models (McAllister three-body, McAllister four-body,\nand Ausländer) were also evaluated. Furthermore, density functional\ntheory, a quantum mechanical approach, was used to assess intra- and\nintermolecular interactions within the binary mixtures.