Propriedades volumétricas, viscosimétricas, acústicas e espectroscópicas de soluções líquidas binárias contendo gama-valerolactona (GVL) e álcoois

Abstract

Substances derived from biomass have called attention, once these compounds belong to the group of renewable solvents, whose physicochemical properties present great potential for applications in several areas of science and industry, namely in biorefineries. Therefore, thermodynamic properties of systems containing such liquids is of practical interest, because experimental data can be used in modeling in order to improve processes or yet to develop and verify new models and solution theories, which have shown their complexity. The present project aims at studying excess thermodynamic properties, that quantify the real solution deviation in comparison to the ideal one, and spectroscopic analyses of binary liquid systems constituted of gamma-valerolactone (GVL) + alcohols (ethanol, 1-propanol, 1-butanol or 1- pentanol). For this purpose, original values of density, speed of sound and dynamic viscosity were determined for these solutions in the whole composition range and in temperatures T = (293.15 – 313.15) K under ambient pressure (92.3 kPa). From these experimental results, it was possible to calculate volumetric properties such as excess molar volume (Vm E ), acoustic property as deviation in isentropic compressibility (??S), viscometric as deviation in viscosity (??) and excess Gibbs energy of activation of viscous flow (?G *E). These properties resulted in negative values at all conditions, except for Vm E , which was totally negative only in ethanol-GVL system. To complete the thermodynamic discussion, both nuclear magnetic resonance (1H-NMR and 13C-NMR) and infrared (ATR-FTIR) spectroscopies have been performed, whose spectra proved the existence of weak hydrogen bondings between GVLalcohol