Molecular dynamics simulation of the structures and properties of deep eutectic solvents

Abstract:

As a new kind of green ionic liquid, deep eutectic solvents have many advantages such as low saturated vapor pressure, low melting point, low price, non-toxicity and degradability, and are widely used in scientific research and engineering applications. Their physical and chemical properties, such as density, viscosity and lattice structure, are the basis for developing solvents with specific functions and their applications. In this work, the density and viscosity of choline-based deep eutectic solvents at 293.15~353.15 K were calculated by molecular dynamics simulation within the framework of GAFF force field, and their average absolute deviations with experimental values in literature were 0.30% and 6.19%, respectively. At the molecular level, the radial distribution function is used to describe the structure distributions in different systems and the formation of hydrogen bonds network. It was found that the extensive hydrogen bonds network of the deep eutectic solvent system was mainly formed by the interaction of Cl atoms and H atoms on hydroxyl, and the interaction decreases with the increase of temperature, and increases with the increase of the length of the hydrogen bond donor alkyl chain. The present study will help us to further study the interaction mechanism between the composition, structure and physical properties of deep eutectic solvents.