SOLVENT EXTRACTION OF METAL IONS WITH NOVEL 4-ACYL-5-PYRAZOLONES HAVING CROWN ETHER MOIETY AS INTRAMOLECULAR SYNERGIST

摘要

Novel 4-acyl-5-pyrazolones having the crown ether moiety as the intramolecular synergist have been synthesized and the solvent extraction of various metal ions are examined. It is expected that the crown ether moiety could behave as the intramolecular synergist and that the selectivity could be governed by the acylpyrazolone and the crown ether parts. These ligands are powerful and selective extracting reagents for alkali, alkaline earth and divalent transition metal ions, and the selectivity is quite unique depending on the intramolecular synergist. Alkali metal ions are readily extracted into chloroform. The selectivity is governed primarily by the crown ether moiety depending on the cavity size. Alkaline earth metal ions are also readily extracted into chloroform, however in this case, the selectivity is governed by both the acylpyrazolone and the crown ether parts. Among the divalent transition metal ions, the extraordinarily high extractability is observed for Mn~(2+), Cd~(2+) and Pb~(2+). Such anomalous extraction is also given in the synergistic extraction of Mn~(2+), Cd~(2+) and Pb~(2+) with acylpyrazolone and benzo-crown ethers used separately.