(352i) Thermodynamic and Spectroscopic Properties of Binary Liquid Solutions Containing Gamma-Valerolactone (GVL) and Alcohols

The knowledge about thermodynamic properties of liquid solutions play one of the most important roles in many operations, since solvents and their mixtures are extremely present in various industrial processes such as extraction, reaction, separation and so forth [1]. In this way, excess properties quantify the deviation from ideality. Molecules do not have only their own energy, but also they share it among them through intermolecular forces, whose intensity reflects the deviation magnitude. Particularly, when a highly self-associated alcohol interacts with another polar chemical species, rupture of hydrogen bonds occur due to specific interactions among unlike molecules.

In this study, density, speed of sound, and dynamic viscosity for binary liquid systems of {gamma-valerolactone (GVL) + 1-propanol, or + 1-butanol, or + 1-pentanol) have been determined at different temperatures (293.15-313.15 K) and ambient pressure (92.3 kPa). These results have been used to calculate excess thermodynamic properties such as excess molar volume, excess partial molar volume, deviations from isentropic compressibility and viscosity, and excess Gibbs energy of viscous flow. Spectroscopic properties (H1-NMR, C13-NMR, ATR-FTIR) have also contributed to take conclusions about possible microscopic phenomena present in the mixtures.

All excess properties showed negative deviations for all temperatures and systems in the whole composition range, except excess molar volumes and excess partial molar volumes, which resulted both negative and positive values in 1-propanol-GVL solutions as well as positive values for 1-butanol-GVL or 1-pentanol-GVL systems. The spectroscopic results showed changes in their bands and chemical shifts as composition varied, proving that hydrogen bonds and dipole-dipole interactions must be predominant among the molecules present in the systems.

References:

[1] Mcglashan, M. L. Pure & Applied Chemistry, 57, 1985.