Combining amino acids and carbohydrates into readily biodegradable, task specific ionic liquids

Abstract

Combining amino acids and carbohydrates yields readily biodegradable ionic liquids with a hydrogen-bond-rich structure.

Insights into the Properties and Potential Applications of Renewable Carbohydrate-Based Ionic Liquids: A Review

“…Chrobok’s group has applied this method to study the glycosylation of d -glucopyranose with halogenoalcohols (e.g., bromoethanol, chloroethanol, 3-chloropropanol, or 3-chloro-1,2-propanediol), generating glycosides with yields of 50% to 78% after purification by column chromatography [ 12 , 15 , 41 , 42 ]. Glycosides can be further quaternized with amines to yield halide salts, which can be applied as task-specific ILs after metathesis with specific anions, such as [NTf 2 ] − [ 12 , 41 ], [MCPA] − , [2,4-D] − [ 15 ], [N(CN) 2 ] − [ 12 ], or amino acid anions [ 42 ]. It has also been reported that triazoles can be obtained via glycosylation of d -xylose with propargyl alcohol, followed by a click reaction and subsequent N -alkylation [ 43 ].…”

“…Combining carbohydrates with other bio-derived molecules (i.e., amino acids) has also been shown to yield readily biodegradable ILs ( 3a – g ), which can be decomposed in 5–6 days in activated sludge [ 42 ]. This result highlights how carbohydrate-derived ILs can be used as alternatives to the cholinium family of ILs ([Ch]ILs), which have emerged as the most readily biodegradable ILs to date [ 5 ].…”

“…Interestingly, a series of amino acid/carbohydrate-based ILs ( 3a – g ) studied in our group revealed the profound influence of the amino acid structure on T d [ 42 ]. Among the studied anions ([Arg] − , [Gly] − , [Ser] − , [His] − , [Leu] − , [Trp] − , and [Tyr] − ), the thermal stability of the corresponding ILs increased with elongation of the amino acid side chain.…”

“…This relationship is evidenced by evaluating the effect of elongating the amino acid side chain. In general, the stronger intermolecular interactions accompanying such elongations resulted in increased viscosities of the derivatives 3a – g [ 42 ].…”

“…Carbohydrate-derived ILs have very good solubility in water, which can facilitate the separation of water-insoluble reaction products and regeneration of the IL for the next reaction cycle. ILs based on carbohydrates and amino acids were successfully utilized as catalysts for the Knoevenagel condensation reaction, where conversion values of 67–94% were achieved following reaction times as short as 15 min under exceptionally mild conditions using water as the solvent [ 42 ]. Moreover, AAILs have been intensively studied in the absorption of greenhouse gases due to the available amino group, suitable for efficient CO 2 , NO x , and SO x capture.…”