Solvent Extraction of Calcium into Nitrobenzene by Using an Anionic Ligand Based on Cobalt Bis(Dicarbollide) Anion with Covalently Bonded CMPO Function

摘要

From extraction experiments and γ-activity measurements, the exchange extraction constantcorresponding to the general equilibrium Ca~(2+)(aq) + 2HL(nb) <=> CaL2(nb) + 2H~+(aq) taking place in the two-phase water-nitrobenzene (L~- = anionic ligand based on cobalt bis(dicarbollide) anion with covalently bonded CMPO function; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K_(ex)(Ca~(2+), 2HL) = 0.0 ± 0.1. Further, the stability constant of the electroneu-tral complex species CaL2 in water-saturated nitrobenzene was calculated for a temperature of 25 °C : log β_(nb) (CaL2) = 11.0 ±0.2.