The distribution ratios, D,of potassium between an aqueous KCl solution and 57 organic solvents (8 alcohols, 12 ketones, 6 esters, 3 ethers, and 28 hydrocarbons(24 halo- and 2 nitro-substituted and 2 unsubstituted)) were determined in the presence or in the absence of L. The presence of L markedly enhances the extractability of potassium when the halogenated hydrocarbon solvents are used, but only a slight enhancement can be observed for the oxygen-containing solvents. Among the properties showing good correlations with D, Hansen’s three-dimensional solubility parameters and Dimroth’s ET values are most satisfactory for their applicability to a wide variety of solvents.
Alkali and alkaline earth metal cations were chromatographed over silica gels and polymer matrices which had been modified by the addition of benzo-15-crown-5, benzo-18-crown-6, and benzo-21-crown-7, using water as the mobile phase. The retention sequences of the cations agreed closely with the stability sequences of the corresponding crown-ether complexes. The best separation was attained on the silica gels modified by the use of benzo-18-crown-6. The retention times increased in this sequence: Li+<Na+<Rb+<Cs+<K+; Mg2+<Ca2+<Sr2+<Ba2+. The retention sequences on the benzo-15-crown-5 and benzo-21-crown-7 columns were Li+<Na+≈Cs+<Rb+<K+ and Li+≈Na+<K+<Rb+≈Cs+ respectively. The resin-based columns showed similar retention sequences, but were inferior in their separation ability to the silica-based ones. The retention times were affected by many factors, such as the cation concentration, the species of the counter anions, the kind and composition of the second solvents in the mixed mobile phase, and the column temperature.
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