Deep Eutectic Solvents in Synthesis Applications

Deep eutectic solvents (DES) are designer mixtures of two or more components—typically a hydrogen-bond donor and a hydrogen-bond acceptor—that form a liquid phase at temperatures markedly lower than those of the individual constituents. Their negligible vapour pressure, tunable physicochemical properties, facile preparation from inexpensive and often renewable feedstocks, and broad solvation capacity have established DES as versatile green media for a wide range of synthetic transformations. In organic chemistry, they function not only as benign reaction media for oxidations, multicomponent condensations and organocatalytic processes but also as active participants when tailored with acid or base functionalities. In materials science, polymerizable eutectic systems serve simultaneously as solvent, monomer and template in the formation of hydrogels, porous monoliths and nanocomposites. In pharmaceutical manufacture, DES enable one‐pot preparations of active intermediates and improve atom economy by eliminating volatile organic co-solvents. Beyond laboratory research, practical applications include the reversible activation of carbon dioxide into cyclic carbonates, metal processing and biomass conversion, underscoring the global importance of DES in sustainable synthesis and industrial scalability.

Research from Nature Portfolio

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Research from all publishers

In a 2024 Chemical Engineering Journal report, polymerizable deep eutectic solvents based on mono- and bis-vinyl imidazolium salts were shown to act as both dispersion media and reactive matrices for multi-walled carbon nanotubes. The study achieved highly functional hybrid materials in under one hour and demonstrated the recovery and reuse of these materials as efficient catalysts for solvent-free conversion of CO₂ into cyclic carbonates without auxiliary co-catalysts. A 2021 Reaction Chemistry & Engineering investigation highlighted the use of DES in organic oxidation reactions, illustrating how hydrogen peroxide–mediated oxidations benefit from DES’s ability to solubilise lipophilic and hydrophilic substrates, immobilise oxidants on solvent components and enable straightforward recycling of the reaction medium. A 2021 study in Molecules detailed choline chloride–based DES as multifaceted agents in pharmaceutical synthesis: these mixtures served as solvents, Brønsted-acid catalysts and even chemical donors in one-pot protocols, enhancing yields of active pharmaceutical intermediates, simplifying downstream separation and allowing solvent recovery.

Deep Eutectic Solvents in Synthesis Applications publication trend

The graph below shows the total number of articles in deep eutectic solvents in synthesis applications across all publications each year (not limited to Nature Index journals).

Technical terms

Deep eutectic solvent (DES): A eutectic mixture of two or more components that achieves a melting point significantly lower than those of its individual constituents, owing to strong intermolecular interactions such as hydrogen bonding.

Natural deep eutectic solvent (NADES): A subset of DES composed of naturally occurring compounds—often plant-derived metabolites—valued for their biodegradability and low toxicity.

Polymerizable eutectic solvent: A DES in which at least one component contains polymerisable functional groups, enabling the solvent itself to participate in polymer formation and templating.

Eutectic point: The specific ratio of components in a mixture at which the lowest possible melting temperature is reached, yielding a homogeneous liquid under ambient conditions.

References

1. Polymerizable deep eutectic solvents: Convenient reactive dispersion media for the preparation of novel multi-walled carbon nanotubes-based functional materials. Chemical Engineering Journal (2024).
2. Deep eutectic solvents: alternative reaction media for organic oxidation reactions. Reaction Chemistry & Engineering (2021).
3. Choline Chloride-Based DES as Solvents/Catalysts/Chemical Donors in Pharmaceutical Synthesis. Molecules (2021).