title: Ion-pair extraction of Na(+), K(+) and Ca(2+) with some organic counter-ions and dicyclohexyl-18-crown-6 as adduct-forming reagent.
abstract: Extraction equilibria of ion-pairs formed by the Na(+), K(+) and Ca(2+) complexes of dicyclohexyl-18-crown-6 and beta- and gamma-dinitrophenol, picric acid and dipicrylamine have been studied in the two-phase system H(2)O/CH(2)Cl(2). Extraction constants and dissociation constants for the ion-pairs in the organic phase are given and show that the efficiency of extraction increases with the hydrophobicity of the counter-ion. At the same time, the selectivity decreases.
authors.affiliation: Department of Analytical Chemistry, The Royal Institute of Technology, S-100 44 Stockholm 70, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Jawaid
authors.forename: F
authors.initials: F
authors.lastname: Ingman