Acute toxicity and biodegradability of N-alkyl-N-methylmorpholinium and N-alkyl-DABCO based ionic liquids

N-Alkyl-N-methylmorpholiniumand N-alkyl substituted1,4-diazabicyclo[2.2.2]octane(DABCO)based ionic liquids(ILs), N-alkyl-DABCO,bearingshortalkylchainsarecharacterisedbyalowtoxicityto Vibrio fischeri, althoughtoxicitysignificantlyincreasesonincreasingthealkylchainlength.Alkylchainlength affects alsobiodegradabilityinthe28daystests;thehigherlevelofbiodegradationwasfoundinboththe series inthecaseoftheethyl(C2)derivatives.Inthecaseof N-ethyl DABCObasedIL,although biodegradabilityisstillaround40%,andconsequentlythisILcannotbeclassifiedas‘‘readilybiodegrad- able’’,thisvalueissimilartothemorebiodegradablefunctionalizedimidazoliumbasedILs.