Preparation, cation-anion interactions and physicochemical properties of ether-functionalized imidazolium ionic liquids

作者：Schrekker Henri S^*; Silva Dagoberto O; Gelesky Marcos A; Stracke Marcelo P; Schrekker Clarissa M L; Goncalves Reinaldo S; Dupont Jairton

来源：Journal of the Brazilian Chemical Society, 2008, 19(3): 426-433.

DOI：10.1590/S0103-50532008000300009

• imidazolium ionic liquids
• ether-functionalized
• hydrogen bonding
• physicochemical properties
• task-specific

A set of 1-alkyl ether (and 1-alkyl)-3-methylimidazolium ionic liquids 2-4 ([C(x)O(y)MIm](+)[Anion](-) or [C(x)MIm](+)[Anion](-), where MIm = 3-methylimidazolium; C(x)O(y) = 1-alkyl ether, C(7)O(3) = -(CH(2))(2)O(CH(2))(2)O(CH(2))(2)OCH(3) (A), C(3)O(1) = -(CH(2))(2)OCH(3) (B) C(x) = 1-alkyl, C(10) = C(10)H(21) (C), C(4) = C(4)H(9) (D); and [Anion](-) = H(3)CSO(3)(-) (2), BF(4)(-) (3) or PF(6)(-) (4)) was prepared and characterized. The cation-anion hydrogen bonding strength showed to be mainly anion dependent and decreased in the order H(3)CSO(3)(-) > BF(4)(-) > PF(6)(-). All methanesulfonate ionic liquids 2 possessed a strongly deshielded H(2) imidazolium ring proton. 1-Alkyl ether functionalized ionic liquids showed higher densities in comparison to their 1-alkyl equivalents. The salts 2a-b, 3a-d and 4a-b are room-temperature ionic liquids. All 1-alkyl ether functionahzed ionic liquids (except 4b) are completely amorphous. The widest liquid ranges were obtained with the tetrafluoroborate ionic liquids due to their late solidification and excellent thermal stability. These data provide important information for the understanding of their application scope and the preparation of task-specific ionic liquids.

• 出版日期2008