Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Extraction of microamounts of Sr²⁺ and Ba²⁺ (henceforth M²⁺) from the aqueous solutions of perchloric acid (0.0125-1.02 mol/l) by means of the nitrobenzene solutions of dicarbolide (0.004-0.05 mol/l of H⁺{Co(C₂B₉H₁₁)₂}^-) was studied in the presence of monoglyme (only Ba²⁺), diglyme, triglyme, and tetraglyme (CH₃O-(CH₂-CH₂O)_nCH₃, where n = 1, 2, 3, 4). The distribution of glyme betweeen the aqueous and organic phases, the extraction of the protonized glyme molecule HL⁺ together with the extraction of M²⁺ ion and of the glyme complex with the M²⁺ ion, i.e., ML²⁺ (where L is the molecule of glyme), were found to be the dominating reactions in the systems under study. In the systems with tri- and tetraglymes the extraction of H⁺ and M²⁺ ions solvated with two glyme molecules, i.e., the formation of HL₂⁺ and ML₂²⁺ species, can probably play a minor role. The values of the respective equilibrium constants, of the stability constants of complexes formed in the organic phase, and the theoretical separation factors α_Ba/Sr were determined. The effect of the ligand structure on the values of extraction and stability constants in the organic phase is discussed.