title: Extraction Selectivities of Crown Ethers for Alkali Metal Cations:  Differences between Single-Species and Competitive Solvent Extractions.
abstract: Separation factor values for pairs of alkali metal cations determined in competitive solvent extractions of alkali metal picrates from aqueous solutions into chloroform by a variety of benzo- and cyclohexano-group-containing crown ethers vary significantly from extrapolations based upon the results of single-species extraction experiments. For almost all of the crown ether-alkali metal cation combinations examined, the separation factor values are greater for competitive solvent extraction. In view of the unexpected results for sodium picrate extraction by dibenzo-24-crown-8, the solid-state structure of the isolated complex was determined.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, and Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336.
authors.forename: G G
authors.initials: GG
authors.lastname: Talanova
authors.forename: N S
authors.initials: NS
authors.lastname: Elkarim
authors.forename: R E
authors.initials: RE
authors.lastname: Hanes
authors.forename: H S
authors.initials: HS
authors.lastname: Hwang
authors.forename: R D
authors.initials: RD
authors.lastname: Rogers
authors.forename: R A
authors.initials: RA
authors.lastname: Bartsch