Understanding the Basics and Properties of Deep Eutectic Solvents
Résumé
The disclosure of deep eutectic solvents represents a landmark in green chemistry. These systems were reported only 17 years ago and yet resulted in a plethora of publications covering various research areas and diverse fields of application. Their economic and straightforward preparation using highly accessible and natural compounds together with their extremely great tunability were enough to consider them as alternatives to the conventional organic solvents. Besides, deep eutectic solvents hold interesting properties suggesting a promising contribution in multiple domains.
Herein, the classification of deep eutectic solvents and the reported preparation methods to date are presented. Further, their physicochemical properties, namely, their phase behavior, density, viscosity, ionic conductivity, surface tension, and polarity, are summarized. The stated properties are affected by various parameters such as the choice of the forming compounds, their molar ratio, the temperature, and the water content. Finally, in the last section, we entirely present the impact of water on both the physicochemical properties and the characteristic supramolecular network of deep eutectic solvents.