Database of deep eutectic solvents and their physical properties: A review

Deep eutectic solvents (DESs) are stable liquids at ambient conditions and generally composed of the binary or ternary compositions of two or three components, which have a significant lower melting point in comparison to their pure components as well as to that of an ideal liquid mixture. DESs are one of the solvents which almost comply with the green solvents criteria by possessing interesting characteristics such as safety, non-toxicity in the case of natural DESs, non-flammability, non-volatility, thermal stability, sustainability, biodegradability, and low cost and they overcome their analogous and organic solvents in most application fields. In this review, we report a database of DESs, which have been prepared from various hydrogen-bond acceptors and hydrogen-bond donors at different molar ratios from 2003 to 2021, along with their reported physical properties including melting point, density, viscosity, conductivity, surface tension, and refractive index. To provide a comprehensive resource to researchers interested in the DESs filed, all the hydrogen-bond acceptors and hydrogen-bond donors used to prepare DESs in different molar ratios along with the effects of type, size and molar ratio of DES constituents as well as temperature on the physical properties have been discussed in this review.