Supramolecular deep eutectic solvents in extraction processes: a review

Solvent selection is essential for industrial and analytical extraction processes to ensure environmental safety and neutrality. Nevertheless, toxic and hazardous solvents are often used, due to their cost-effectiveness and ready availability. In green chemistry, alternative solvents such as supramolecular deep eutectic solvents are gaining attention due to their superior performance compared with traditional non-green solvents in certain applications. Here we review the use of supramolecular deep eutectic solvents as a green solvent for analytical and industrial liquid–liquid extraction processes, with focus on physicochemical properties, extraction conditions, the capacity factor, the enrichment factor, fuel desulfurization, extraction of biological active compounds, lignin valorization, and sample preparation.