Toxicity of various anions associated with methoxyethyl methyl imidazolium-based ionic liquids on Clostridium sp

• Published in: Chemosphere (Oxford) 2011-03, Vol.82 (11), p.1597-1603
• Main Authors: Wang, Hao, Malhotra, Sanjay V., Francis, Arokiasamy J.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Anions; Anions - chemistry; Anions - toxicity; Applied ecology; Atomic properties; Bacteria; Biodegradation, Environmental; Biological and medical sciences; Cations; Clostridium; Clostridium - drug effects; Clostridium - growth & development; Clostridium sp; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Fluorine; Fundamental and applied biological sciences. Psychology; General aspects; Green Chemistry Technology; Hydrogen-Ion Concentration; Imidazoles - chemistry; Imidazoles - toxicity; Ionic liquids; Ionic Liquids - chemistry; Ionic Liquids - toxicity; Toxic; Toxicity; Toxicology
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2010.11.049

► We investigate the toxicity of various anions associated with 1-methoxyethyl-3-methyl imidazolium on the growth of anaerobic bacterium, Clostridium sp. ► The higher concentration of ionic liquid, the more inhibition it demonstrates. ► Anions incorporating fluorine are more toxic than those without it, and their toxicity rises with an increase in the number of fluorine atoms. ► Addition of a methoxyethyl functional group to the side chain of the imidazolium cation renders it less toxic. We investigated the effects on the growth of the anaerobic bacterium, Clostridium sp., of the ionic liquid, 1-methoxyethyl-3-methyl imidazolium [MOEMIM]+, derived from imidazolium cation and paired with one of a variety of counter-ions, viz., tetrafluoroborate [BF4]-, hexafluorophosphate [PF6]-, trifluoroacetate [CF3COO]-, bis(trifluoromethane)sulfonamide [Tf2N]-, methane sulfonate [OMS], and 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4]. These anions, in association with [MOEMIM]+ lowered the growth rate of the bacterium, showing the following trend: [Tf2N]-≧[PF6]->[BF4]->[CF3COO]->[OMS]−. Anions incorporating fluorine were more toxic than those without it, and their toxicity rose with an increase in the number of fluorine atoms. Also, [MOEMIM]+[BF4]- was less toxic than [BMIM]+[BF4]-, probably due to the presence of a methoxyethyl functional group integrated in the cation side chain.