Use of deep eutectic solvents as catalyst: A mini-review

Deep eutectic solvents (DESs) exhibit numerous advantages over conventional ones used in several chemical and biochemical processes. Besides addressing most of the principles of green chemistry, DESs can also act as catalyst depending on their nature. The use of DESs as acid catalyst has several advantages such as utilization at stoichiometric amount, non-toxicity, possibility of the recovery, similar or higher catalytic effect than the acid itself alone, the recyclability and reusability without a significant loss of activity. In this mini-review, the state- of-the-art in the use of DESs as catalyst is presented. The DESs, which show Lewis type acidity, Brønsted type acidity and other types of catalytic influence in various types of reactions including esterification, organic synthesis, glycolysis and depolymerisation are presented and their roles in the reactions are discussed