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A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids
Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, Joan XXIII s/n, 08028 Barcelona, Spain
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Received: 29 February 2012; in revised form: 20 March 2012 / Accepted: 23 March 2012 / Published: 2 April 2012
Abstract: A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form) in non-aqueous media. The anion loading of the AER (OH− form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7) and the anion exchange was equally successful with both lipophilic cations and anions.
Keywords: imidazolium salts; pyridinium salts; ammonium salts; anion exchange resin; counteranion exchange; ionic liquids
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Alcalde, E.; Dinarès, I.; Ibáñez, A.; Mesquida, N. A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids. Molecules 2012, 17, 4007-4027.
Alcalde E, Dinarès I, Ibáñez A, Mesquida N. A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids. Molecules. 2012; 17(4):4007-4027.
Alcalde, Ermitas; Dinarès, Immaculada; Ibáñez, Anna; Mesquida, Neus. 2012. "A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids." Molecules 17, no. 4: 4007-4027.