Insight into the physicochemical properties of deep eutectic solvents by systematically investigating the components

Abstract

Deep eutectic solvents (DESs) have been recognized as environmentally friendly alternatives to the conventional fossil solvents, which are in consistent with the concept of green chemistry. In order to offer theoretical guidance for designing DESs with specific physicochemical properties, the structure–function relationships between the molecular structures of DESs components and their physicochemical properties were systematically analyzed. The investigation of the functional groups, carbon chain length and type of halogen ions in DESs components provided a deeper understanding of the formation and properties of DESs. Density, viscosity, solvatochromic parameters (ENR value、π* value、α value and β value) were selected as the analyzable physicochemical properties. Except for the conclusion about the proper hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) for DESs with specific physicochemical properties, an effective neural network model system was also provided for the prediction of DESs properties. The molecular structural parameters of DESs used as input layers were calculated from the initial and constant molecular structural parameters of HBAs and HBDs. Not only considerable time was saved without complex calculation of the interactions energy between components, it was also helpful in constructing comprehensive database of the molecular information of the DESs components to provide convenience for future research.