title: Fluorous ionic liquids as solvents for the liquid-liquid extraction of metal ions by macrocyclic polyethers.
abstract: The predominant mode of strontium ion transfer from aqueous nitrate media into a series of 1-fluoroalkyl-3-methylimidazolium bis[(trifluoromethylsulfonyl)]imides containing dicyclohexano-18-crown-6 (DCH18C6) is shown to shift from cation exchange to strontium nitrato-crown ether complex partitioning as the length of the fluoroalkyl substituent is increased. Fluoroalkyl substituents are shown to be only slightly more effective than their non-fluorous analogs at inducing this shift. At the same time, the fluorinated ionic liquids (ILs) yield strontium distribution ratios as much as an order of magnitude lower than the corresponding 1-alkyl-3-methylimidazolium (C(n)mim(+)) salts. Fluorous ILs thus appear to offer no compelling advantages over C(n)mim(+) ionic liquids as extraction solvents.
authors.affiliation: Chemistry Division, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: Holly
authors.initials: H
authors.lastname: Heitzman
authors.forename: Blake A
authors.initials: BA
authors.lastname: Young
authors.forename: David J
authors.initials: DJ
authors.lastname: Rausch
authors.forename: Paul
authors.initials: P
authors.lastname: Rickert
authors.forename: Dominique C
authors.initials: DC
authors.lastname: Stepinski
authors.forename: Mark L
authors.initials: ML
authors.lastname: Dietz