T. Maeda, K. Kimura, T. Shono
Nov 1, 1982
Citations
0
Influential Citations
33
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
Solvent extractions of alkali metal picrates were carried out using newly synthesized poly- and bis(crown ether)s containing benzo-12-crown-4 moieties in a water-chloroform system. The extraction equilibrium constants(Ke) and the complexation constants (Kc) in the chloroform phase were determined at 25 °C. The Ke values for the alkali metal cations decreases as follows: Na+>K+>Rb+≥Cs+ with the poly(benzo-12-crown-4) and K+, Rb+, Cs+>Na+ with the bis(benzo-12-crown-4). The poly(benzo-12-crown-4) improved the sodium-ion selectivity of the corresponding monocyclic analog because of the easy formation of 2:1 crown ether unit-cation complexes assisted by the cooperative action of two adjacent crown ether units, while the bis(benzo-12-crown-4) did not. A separate extraction experiment was also undertaken in a water-dichloromethane system in order to compare the extractability of these benzo-12-crown-4 derivatives with that of 12-crown-4.