Implicit and explicit solvent models to understand the d(+)-glucose solvation in aqueous protic ionic liquid solution: Volumetric and computational approach

Abstract

The nature of interactions between biopolymers (polysaccharides) and ionic liquids (ILs) governs the dissolution/functionalization processes, so an understanding of these interactions demands reliable reference data on thermophysical properties of systems composed of biopolymer model compound (monosaccharide), ILs and solvent (water). In this regard, we report herein the volumetric properties of d(+)-glucose (Glu) in aqueous solutions of protic ionic liquid (propylammonium formate; PAF) at different concentrations and temperatures. The experimental results were further supported by computational studies. Structures of Glu and PAF were optimized in gas phase by employing density functional theory at CAM-B3LYP/6-311G++ (2d, 2p) level. Further, interactions between the two in presence of solvent (water) were studied by employing implicit as well as explicit solvent models. The hydrophilic-ionic interactions between Glu and PAF are significant at lower concentrations of PAF and diminish with increasing concentration of PAF as well as temperature. Overall, hydrophobic type of interactions between Glu and ions of PAF dominate the solvation behaviour at higher concentration and temperature, and these observations have been further supported by computational results.