Study on solute–solvent and solute–solute interactions for the dibenzo-24-crown-8-alkali metal picrate extraction system
書誌事項
- 公開日
- 2004-11
- 権利情報
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- https://www.elsevier.com/tdm/userlicense/1.0/
- DOI
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- 10.1016/j.molliq.2004.04.003
- 公開者
- Elsevier BV
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説明
Abstract The constants of overall extraction equilibrium (Kex) and distribution (KD,MLA) for various diluents and aqueous ion-pair formation (KMLA) of dibenzo-24-crown-8 (DB24C8)–alkali metal (Na–Cs) picrate (MA) 1:1:1 complexes (M(DB24C8)A) were determined at 25 °C; the partition constants of DB24C8 were also measured at 25 °C. The distribution behavior of DB24C8 and M(DB24C8)A complexes can be explained by regular solution theory; the molar volumes and the solubility parameters of DB24C8 and M(DB24C8)A were determined. The log KD,MLA value for the same diluent decreases from Na to K and increases from K to Cs; however, the reverse is true of the log KMLA values. The extraction selectivity of DB24C8 for the alkali metal picrates decreases in the order Cs>Rb>K>Na or Cs>K≥or >Rb>Na. This is governed largely by the aqueous stability order for the M(DB24C8)+ complex ions. For every diluent, the plot of log Kex values against the reciprocal effective ionic radii of the alkali metals gives a straight line, which is related to Born's formula of solvation free energy. The reason for this was elucidated.
収録刊行物
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- Journal of Molecular Liquids
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Journal of Molecular Liquids 115 (2-3), 139-147, 2004-11
Elsevier BV