Chiral Solvent Discovery: Exploring Chiral Eutectic Mixtures and Deep Eutectic Solvents

Deep eutectic solvents (DES) are mixtures that have a melting point much lower than any of the components. Because the properties of DES, such as chiral discrimination, can be controlled through choice of components, DES have potential as solvents in many chemical and industrial applications. However, the large number of potential components makes high throughput methods of DES discovery critical for their development. In this study, mixtures of small quantities of hydrogen bond acceptors (HBAs) and chiral hydrogen bond donors (HBDs) were mixed at 55 °C and cooled to 20 °C to screen for potential liquid formation. Variable molar ratios of 10 HBAs were mixed with 93 chiral HBDs to measure a total of 1250 mixtures, and 356 mixtures were liquid at 20 °C. All of the results including mixtures that did not form liquids are provided in a publicly available database. Several of the mixtures were prepared in larger quantities to characterize their physical properties, including melting points, densities, and viscosities. The results of this study can be used to guide the discovery and development of new chiral solvents, such as DES and eutectic mixtures.