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A Simple and Practical Method for the Preparation and Purity Determination of Halide‐Free Imidazolium Ionic Liquids
Author(s) -
Cassol Claúdia C.,
Ebeling Günter,
Ferrera Bauer,
Dupont Jairton
Publication year - 2006
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200505295
Subject(s) - chemistry , ionic liquid , dichloromethane , halide , alkyl , yield (engineering) , extraction (chemistry) , solvent , inorganic chemistry , ionic bonding , filtration (mathematics) , organic chemistry , catalysis , ion , statistics , mathematics , materials science , metallurgy
Abstract The reaction of N ‐alkylimidazole with alkyl sulfonates at room temperature affords 1,3‐dialkylimidazolium alkanesulfonates as crystalline solids in high yields. The alkanesulfonate anions can be easily substituted by a series of other anions [BF 4 , PF 6 , PF 3 (CF 2 CF 3 ) 3 , CF 3 SO 3 and N(CF 3 SO 2 ) 2 ] by simple reaction of anions, salts, or acids in water at room temperature. Extraction with dichloromethane, filtration through a short basic alumina column and solvent evaporation affords the desired ionic liquids in 80–95% yield. The purity (>99.4%) of these ionic liquids can be determined by 1 H NMR spectra using the intensity of the 13 C satellites of the imidazolium N ‐methyl group as internal standard.