Effect of chain length of alkane-1-hydroxy-1, 1′-methyldiphosphonic acids on the iron (III) liquid -: Liquid extraction

(1-Hydroxy-1-phosphonohexadecyl) phosphonic acid (HPHPA) and (1-hydroxy-1-phosphonododecyl) phosphonic acid (HPDPA) were prepared by reaction of phosphorus trichloride with palmitic and lauric acids, respectively. After purification, these products were characterized by elemental microanalysis and by IR, H-1, (PNMR)-P-31 spectroscopies. In this paper, we propose a tentative assignment for the shifts of those two ligands and their specific complexes with iron (III). A spectroscopic analysis has showed that coordination of iron (III) takes place via oxygen atoms. We also measured the extraction of Fe 13 by HPHPA and HPDPA from [CCl4-Octanol (v/v: 90%/10%)] solutions. The complexes formed in the organic phase may be Fe[Cl, H23C(OH)(PO3H)(2)]Cl, 3H(2)O with HPDPA and Fe[C15H31C(OH) (PO3H)(2)]Cl, 3H(2)O with HPHPA, respectively. HPHPA as ligand exhibits a stronger extracting power for Fe3+ and has a more hydrophobic character than HPDPA.