Solvent Extraction of Microamounts of Calcium into Nitrobenzene Using Hydrogen Dicarbollylcobaltate and 2,3-Naphtho-15-crown-5

Emanuel Makrlík,1,* Petr Vaňura2 and Pavel Selucký3

1 Faculty of Applied Sciences, University of West Bohemia, Husova 11, 306 14 Pilsen, Czech Republic
2 Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague, Czech Republic
3 Nuclear Research Institute, 250 68 Řež, Czech Republic
* Corresponding author: E-mail: makrlik@centrum.cz

Abstract
Extraction of microamounts of calcium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B–) in the presence of 2,3-naphtho-15-crown-5 (N15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2+, CaL2+ and CaL22+  are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

Keywords: Calcium, hydrogen dicarbollylcobaltate, 2,3-naphtho-15-crown-5, extraction and stability constants, water
– nitrobenzene system