Hydrophobic Deep eutectic Solvents based on cineole and organic acids

Abstract

The hydrophobic Natural Deep Eutectic Solvent formed by the combination of cineole and decanoic acid (capric acid) was studied using a combined experimental and computational approach. Experimental study was carried considering relevant physicochemical properties as density, viscosity, refraction index and thermal conductivity as a function of temperature, as well as Raman spectra for 785 nm excitation wavelength. Thermophysical properties measured showed a low -viscous low-dense fluid, which is of great relevance for its technological application, as well as the Raman spectra confirmed the formation of hydrogen bonding. The analysis of nanoscopic properties and structuring was carried out using theoretical method as the Density Functional Theory (BP86/def2-TZVP plus Grimme’s D3 theoretical level) and classical Molecular Dynamics simulation (using AMOEBA polarizable force field). Molecular modelling studies using quantum chemistry and classical molecular dynamics methods allowed a nanoscopic characterization of the fluid as well as of its intermolecular forces (hydrogen bonding). Phase equilibria were predicted using COSMO method considered solid–liquid (melting behavior) and vapor – liquid (evaporation), as well as excess properties. The COSMO results showed a low volatile, wide liquid range fluid, characterized by non-ideality because of the formation of hydrogen bonding. Likewise, the interaction of the considered material with POPC lipid was studied using COSMOperm method to analyze its behavior at lipid bilayers as models of cell membranes for the consideration of its possible toxicological effects, showing how the considered molecules are able to penetrate and disrupt the model membranes because of the lipophilic nature of the considered molecules.