Theoretical investigation on the structure and physicochemical properties of choline chloride-based deep eutectic solvents

• Published in: Journal of molecular liquids 2022-11, Vol.366, p.120243, Article 120243
• Main Authors: Han, Peixing, Nie, Wenjie, Zhao, Guanjia, Gao, Peng
• Format: Article
• Language: English
• Subjects: Deep eutectic solvents; Density; Hydrogen bond; Molecular dynamic simulation; Radial distribution function; Viscosity
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2022.120243

•Five choline-based deep eutectic solvents (DESs) were studied by molecular dynamics simulation.•Density and viscosity of the studied DESs were calculated at 293.15–353.15 K.•The formation and main sites of hydrogen bonding were discussed in terms of DES structure.•The effects of temperature on the behaviour of the DES system were investigated.•The relationships between nanostructure and physicochemical properties of the DES were analysed. Deep eutectic solvents (DESs) are analogous to ionic liquids that have been widely employed in scientific research and engineering applications. The physicochemical properties of DESs, including the density, viscosity, and nanostructure, serve as the foundation for green solvent development. In the present work, the density and viscosity of choline-based DESs at 293.15–353.15 K were simulated using molecular dynamics (MD) simulation under the Generation Amber Force Field. The radial distribution function (RDF) and number of hydrogen bonds of the selected systems were analysed. It was found that a large amount of the hydrogen bonding network was formulated between chlorine and hydrogen atoms in hydroxyl groups, which greatly decreased the melting temperature of the solvent in comparison with the pure components. The intermolecular interaction decreased with increasing temperature as well as the length of the alkyl chain on the hydrogen bond donor (HBD). Furthermore, an increase in the number of hydroxyl groups in HBD molecules leads to the formation of a more complex and extensive hydrogen bond network, which results in a higher viscosity of the DES.