The development of ionic liquids (ILs) with reduced viscosities and increased conductivities would be advantageous for many practical applications including as non-flammable electrolytes in energy storage devices like batteries. ILs containing bis(trifluoromethylsulfonyl)amide (NTf2–) anions have been shown to exhibit many favorable properties including reduced viscosities and recently ILs with related sulfonamide anions have been reported. In this work we explore the effect of varying the lengths and fluorination of side chains on sulfonamide anions of pyrrolidinium and imidazolium ILs on their physical properties. The ILs were prepared by first reacting 1-methylimidazole or 1-methylpyrrolidine with an alkylhalide of the desired chain length to produce the imidazolium or pyrrolidinium halide salts. The halide salts were then converted to ionic liquids via metathesis in water with the lithium or potassium salts of the fluorous anions: NTf2, bis(pentafluoroethylsulfonyl)amide (BETI), bis(fluorosulfonyl)amide (FSA), (nonafluorobutyl)sulfonyl(trifluoromethyl)sulfonyl amide (IM14) and (fluorosulfonyl) (trifluoromethyl)sulfonyl amide (IM10). The structures of the ILs were confirmed using 1H, 13C, and 19F Nuclear Magnetic Resonance (NMR) spectroscopy. The ILs were characterized for their physical properties including conductivity, viscosity and thermal profile. Results reveal that (nonafluorobutylsulfonyl)(trifluoromethylsulfonyl)amide (IM1,4) ILs have the least favorable transport properties while bis(fluorosulfonyl)amide (FSA) ILs have the most favorable transport properties in this family of ILs.

Exploring the effect of fluorinated side chains in a family of sulfonamide ionic liquids

256th National Meeting (2018)

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