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We report the synthesis, characterization and cellulose dissolution properties of a series of ionic liquids bearing alkyl and hydroxyl-functionalized imidazolium and pyrrolidinium cations, and dial...

Binary mixtures of ionic liquids (ILs) were prepared and characterized to obtain ILs with viscosity and conductivity properties optimized for use in energy storage devices such as supercapacitors. The bis(trifluoromethylsulfonyl)amide anion (NTf2 -) was the common anion for both ILs in the mixture. Ethoxyethyl was the common substituent on the solute and solvent, as ether substituents have been shown to produce low viscosity ILs. N-Ethoxyethyl-N-methylpyrrolidinium NTf2 was used as the solvent for all of the IL mixtures. The solutes were either monocationic or dicationic and made up 10% of the binary mixture by weight. We report here on the physical properties of the individual ILs and their binary mixtures.

The need for improved energy storage capability in supercapacitors has prompted the use of ionic liquids as alternatives to acetonitrile based solvents. Despite the advantages of supercapacitors, their use in transportation is not favorable because of the deterioration of organic solvents with increasing temperatures and their high vapor pressures. We report here on the synthesis and characterization of ionic liquids optimized for use in supercapacitors. The cations were designed to bear ether substituents which are known to lower the viscosity of ILs. ILs and binary mixtures of ILs based on pyrrolidinium, imidazolium and dicationic ammonium cations bearing ether substituents and bis(trifluoromethylsulfonyl)amide [NTf2 -] anions have been synthesized, purified and characterized. The halide salts were synthesized by reaction of the amine with 2-bromoethylethylether. They were then converted to the NTf2 salts after purification. The structures of the salts were confirmed using H-1 and C-13 Nuclear Magnetic Resonance spectroscopy. The dicationic ILs were used as the solutes in the binary IL mixyures. The binary IL mixtures have been analyzed for their transport properties using NMR. The work at BNL was supported by the BNL Office of Educational Programs and the DOE Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract # DE-AC02-98CH10886.