Anion effect on selectivity in solvent extraction of alkali metal salts by crown ethers

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Solvent Extraction and Ion Exchange

DOI:https://doi.org/10.1080/07366299508918313· OSTI ID:137385

Hankins, M G; Bartsch, R A ^[1]; Olsher, U ^[2]

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1. Texas Tech Univ., Lubbock, TX (United States)
2. Weizmann Inst. of Sciences, Revovat (Israel)

The influence of the co-extracted anion upon competitive solvent extraction of five alkali metal cations from aqueous solutions into organic diluents by the cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 has been assessed. The anions are bromide, chloride, iodide, nitrate, perchlorate, and thiocyanate and the organic diluents are chloroform and 1-octanol. The extraction efficiency is markedly influenced by the identity of the anion and exhibits some correlation with the inverse of the hydration enthalpy of the anion. Although potassium is the best exctracted cation with all anions, the selectivities for potassium over lithium, sodium, rubidium, and cesium are strongly affected by anion variation in chloroform, but not in 1-octanol. The selectivity ordering in chloroform does not correlate with the hydration enthalpy or softness parameter for the anion. Instead it appears to result from variation of the dimensional structure and the availability of specific binding sites in the anion. 21 refs., 1 fig., 5 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 137385
• Journal Information: Solvent Extraction and Ion Exchange, Journal Name: Solvent Extraction and Ion Exchange Journal Issue: 6 Vol. 13; ISSN 0736-6299; ISSN SEIEDB
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ALKALI METAL COMPOUNDS
ANIONS
BROMIDES
CESIUM IONS
CHLOROFORM
CROWN ETHERS
EXPERIMENTAL DATA
IODIDES
LITHIUM IONS
NITRATES
OCTANOLS
PERCHLORATES
POTASSIUM IONS
RUBIDIUM IONS
SALTS
SODIUM IONS
SOLVENT EXTRACTION
THIOCYANATES