Assessment and design of greener deep eutectic solvents - A multicriteria decision analysis

Deep eutectic solvents (DES) are often considered as green solvents because of their properties, such as negligible vapor pressure, biodegradability, low toxicity or natural origin of their components. Due to the fact that DES are cheaper than ionic liquids, they have gained many applications in a short period of time. However, claims about their greenness sometimes seem to be exaggerated. Especially, bearing in mind lots of data gaps for DES properties as well as their individual components. To clarify the situation on their greenness status, a comprehensive assessment of commonly used hydrogen bond acceptors and donors separately and as DES is performed. The application of multicriteria decision analysis (TOPSIS ranking) with combination of biological effect modeling for DES to rank these alternatives according to greenness criteria is proposed. Also traditional organic solvents and ionic liquids as greenness reference points for better understanding are introduced. The ranking results show that many DES, which are synthetized by mixing sugars alcohols, alcohols, sugars and amides are promising environmentally friendly solvents, more than some imidazolium-based ionic liquids. Mixtures including components with metal ions and organic acids are less green. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Deep eutectic solvents (DES) are considered green solvents due to their properties such as low vapor pressure and biodegradability, but claims about their greenness can be exaggerated. A comprehensive assessment of their components is needed, alongside the use of multicriteria decision analysis and biological effect modeling to rank their greenness. The ranking results show that DES synthesized by mixing sugars alcohols, alcohols, sugars, and amides are promising environmentally friendly solvents, while mixtures with metal ions and organic acids are less green.