Low toxicity functionalised imidazolium salts for task specific ionic liquid electrolytes in dye-sensitised solar cells: a step towards less hazardous energy production
This invention relates to ionic liquid (ILs) solvents for chemical synthesis based on an alkyl-imidazolium cation core containing ionic liquids which have enhanced biodegradability and reduced toxicity relative to existing imidazolium bases ILs such as 1-butyl-3-methylimidazolium (bmmim) salts. Many of the described ILs produce a score of over 60% biodegradability over 28 days in a biodegradability test such as the Sturm Test, the Closed Bottle Test (OECD 301D) or the CO
2
Headspace Test (ISO 14593). The ILs of the invention comprise an alkyl substituted imidazolium cationic core having a —C═OX— side chain in the 3-position of the imidazole ring, wherein X═O, NH, N or S and an associated counteranion characterized in that the —C═OX side chain comprises at least one ether linkage. The biodegradable and non-toxic IL may be used as green solvents for the chemical, pharmaceutical, biofuel and biomass industries. The ILs of the invention are particularly useful in hydrogenation, pericyclic and metathesis reactions.
A series of imidazolium ionic liquids was prepared and screened against 7 bacterial strains. The incorporation of ether groups into the ester side-chain significantly reduced the toxicity compared with alkyl ester derivatives. Biodegradation data are also presented for 15 of the ionic liquidsâincluding 6 examples which can be classed as readily biodegradable.
Low toxicity functionalised imidazolium salts for task specific ionic liquid electrolytes in dye-sensitised solar cells: a step towards less hazardous energy production