Collect. Czech. Chem. Commun. 1984, 49, 39-44

Contribution to the thermodynamics of complexes of alkali metal cations with dibenzo-18-crown-6 in water-nitrobenzene extraction system

Emanuel Makrlík, Jaroslava Hálová and Miroslav Kyrš

Institute of Nuclear Research, 250 68 Řež


The stability constants for the ML+ complex species, where M+ is an alkali metal cation and L is dibenzo-18-crown-6, in nitrobenzene saturated with water were calculated by employing published equilibrium data. The stability is found to increase in the cation order Li+ < Cs+ < Rb+ < K+ < Na+. For the NaL+, KL+, RbL+, and CsL+ complex cations the individual extraction constants in the water-nitrobenzene system were determined; their values increase in the series Na+ < K+ < Rb+ < Cs+.