(382u) Density, Speed of Sound and Viscosity for Binary Liquid Mixtures Containing Gamma-Valerolactone (GVL) + Ethanol at Different Temperatures

Liquid solutions are very common in industry, namely in chemical processes such as extraction, separation and hydrolysis. The knowledge of thermodynamic and physicochemical properties of their real behavior is extremely necessary to try to understand the chemical, physical and structural phenomena present in the systems. Biorefineries have been seen as sustainable and promising since they produce chemicals from biomass, substituting partially products derived from crude oil [1]. Acidic hydrolysis of biomass leads to mainly both compounds: levulinic acid (LA) and formic acid. LA is a key molecule to biorefinery since it can be the origin of many other high value products, for example, gamma-valerolactone (GVL), which is known as a building block. Moreover, GVL properties favor its use as a solvent as well as an ideal precursor to alkanes, fuel and food production [2]. In the present study, experimental values for density, speed of sound and viscosity for the binary liquid mixtures of GVL + ethanol as a function of composition at T = (293.15 - 313.15) K and ambient pressure were determined. These results have been used to determine volumetric properties (excess molar volume, partial molar volumes, excess partial molar volumes and apparent molar volumes), acoustic properties (deviation in isentropic compressibility), viscometric properties (deviation in viscosity and excess Gibbs energy of activation of viscous flow ΔG*^E). The excess properties were fitted to the Redlich-Kister equation. Moreover, spectroscopic properties (FT-IR, ¹H NMR and ¹³C NMR) have been investigated to elucidate the main structural and interactional phenomena present in the system studied.

A commercial density and speed of sound analyzer manufactured by Anton Paar (Model DSA 5000) were used to measurement the densities and speeds of sound of pure components and their solutions. The viscosity values were measured using a Stabinger viscometer (SVM 3000/G2) also manufactured by Anton Paar. Analyses of ¹H-NMR and ¹³C-NMR were carried out by an Avance III 600 HD Bruker spectrometer at 600 MHz for proton and 150 MHz for carbon. Finally, a Fourier transform infrared spectroscopy Nicolet with attenuated total reflectance (FTIR-ATR) (Model 6700) generated the IR spectra. The behavior of excess molar volume, deviations in isentropic compressibility, deviations in viscosity, and excess Gibbs energy of activation were negative over the whole composition range and for all temperatures studied. The thermodynamic and spectroscopic results indicate specific interactions between the unlike molecules present in the system.

References

[1] Strappaveccia G.; Luciani L.; Bartollini E.; Marrocchi A.; Pizzo F.; Vaccaro L. Green

Chem., 17 (2015) 1071.

[2] Gustavo Metzkera G.; Burtoloso A.C.B. Chem. Commun., 51 (2015) 14199.