Z. Naturforsch. 2013, 68b, 1154 – 1162
Synthesis and Sorption Analysis of Task-specific Fluorous Ionic Liquids
Verena Adamer, Gerhard Laus, Ulrich J. Griesser, and Herwig Schottenberger
Faculty of Chemistry and Pharmacy, University of Innsbruck, 6020 Innsbruck, Austria
Reprint requests to Prof. Dr. Herwig Schottenberger. Fax: (+43) 512 507 57099. E-mail: herwig.schottenberger@uibk.ac.at
Received June 3, 2013 / published online October 4, 2013
Six 1-alkyl-4-tridecafluorooctyl-1,2,4-triazolium triflimides 2af and 4-amino-1-tridecafluorooctyl-1,2,4-triazolium triflimide (4) were prepared from the respective iodides 1af (1a, 2a: n-propyl; 1b, 2b: n-butyl; 1c, 2c: n-hexyl; 1d, 2d: n-heptyl; 1e, 2e: n-octyl; 1f, 2f: n-decyl) and iodide 3 by ion metathesis. Compounds 2a and 4 are liquid at room temperature. Two liquid fluorous imidazolium salts bearing functionalized polar substituents were synthesized in an analogous manner, namely 1-(2-(diethylamino)ethyl)-3-(heptadecafluorodecyl)imidazolium triflimide (5b) and 1-(2-hydroxyethyl)-3-(heptadecafluorodecyl)imidazolium triflimide (6b) from the respective bromides 5a and 6a. The bis(triflimide) 5c has a melting point slightly above room temperature. Three fluorous ionic liquids (ILs; 2a, 5b, and 6b) were subjected to vapor sorption analysis at 25 °C and exhibited dual affinity to water and, even much more pronounced, to methoxynonafluorobutane (hydrofluoroether HFE-7100). Thus, IL 6b absorbed 3.2 % (by weight) water and 200 % HFE, whereas ILs 2a and 5b absorbed 0.4 and 0.5 % water, but 300 and 1200 % HFE, respectively. Commercial 1-butyl-2,3-dimethyl-imidazolium triflimide and 1-ethyl-3-methyl-imidazolium triflimide were used as reference compounds and absorbed 0.9 and 2.2 % water, respectively, but only 17 % HFE.
Key words: Fluorous, Hydrofluoroether, Imidazole, Ionic Liquid, Sorption, Triazole
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