Solvent extraction of divalent transition metal ions with diaza-crown ethers having two acylpyrazolone moieties

The solvent extraction of the divalent transition metal ions (Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) has been examined with 4-acyl-5-pyrazolones having a diaza-crown ether moiety as the intramolecular synergist. It is expected that the diaza-crown ether moiety could behave as the intramolecular synergist and that the extractions could be governed by both the acylpyrazolone and the diaza-crown ether. It was found that divalent transition metal ions were readily extracted into chloroform, and the selectivity depended on the intramolecular synergist.