A multivariate insight into ionic liquids toxicities

Abstract

A multivariate insight into Ionic Liquids' (ILs) toxicity, a broad term highly dependent on the biological systems adopted as “sensors”, addressed four main groups of toxicities: aquatic toxicity, toxicity towards fungi and bacteria, cytotoxicity towards IPC-81 rat cell lines and acetylcholinesterase enzyme inhibition. This approach, summarizing toxicity information available from a huge amount of scattered literature data, allowed derivation of aquatic toxicity scores for 104 ILs and bacteria and fungi toxicity scores for 87 ILs as well as identification of a correlation between aquatic ecotoxicity and the response of IPC-81 rat cell lines. Further evidence on the effects of cation structural features such as the increase of IL toxicity on increasing the length of the side chain and its decrease when oxygen atoms are present in the side chain was obtained. Maximum dialkyloxyether imidazolium toxicity was observed for ILs having 7–9 carbon atoms in each side chain, while toxicity decreased for ILs with a higher number of carbons, probably due to the formation of micellar aggregates.