Antibacterial, Antifungal and Ecotoxic Effects of Ammonium and Imidazolium Ionic Liquids Synthesized in Microwaves.

Jana Fojtášková,Lucie Obalová,Milan Maxa,Hana Sezimová,Petr Pánek,Martina Vráblová,Ivan Koutník

doi:10.3390/molecules25215181

Jana Fojtášková, Lucie Obalová + Show 5 more

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https://doi.org/10.3390/molecules25215181

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Abstract

Ionic liquids are increasingly used for their superior properties. Four water-immiscible ionic liquids (butyltriethylammonium bis(trifluoromethylsulfonyl)imide, octyltriethylammonium bis(trifluoromethylsulfonyl)imide, dodecyltriethylammonium bis(trifluoromethylsulfonyl)imide, butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and their water miscible precursors (bromides) were synthesized in a microwave reactor and by conventional heating. The best conditions for microwave-assisted synthesis concerning the yield and the purity of the product are proposed. The heating in the microwave reactor significantly shortened the reaction time. Biocide and ecotoxic effects of synthesized ionic liquids and their precursors were investigated. All tested compounds had at least a little effect on the growth or living of microorganisms (bacteria or mold). The precursor dodecyltriethylammonium bromide was found to be the strongest biocide, but posed a risk to the aquatic environment due to its relatively high EC50 value in the test with Vibrio fischeri. We assumed that apart from the alkyl chain length, the solubility in water, duration of action, or type of anion can influence the final biocide and ecotoxic effect.

Highlights

Ionic liquids (IL) are increasingly used for their superior properties
The classical synthesis of tetraalkylammonium and imidazolium salts is a well-studied synthesis that leads to products of high purity
The reaction time for classical synthesis is on the order of tens of hours to days

Summary

Introduction

Ionic liquids (IL) are increasingly used for their superior properties. Their typical feature is a melting point below 100 ◦ C. Room temperature ionic liquids (RTILs) are of particular interest for practical applications. Thanks to this property, they can replace common solvents; they can dissolve organic, inorganic, organometallic, and polymeric substances. The main advantage of ionic liquids includes the very low vapour pressure caused by their ionic character. Due to this, they are considered as green substitutes for volatile organic industrial solvents. This feature reduces the risk of exposure and solvent loss due to evaporation, thereby reducing air pollution [1]

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