INFRARED STUDIES OF BIFUNCTIONAL EXTRACTANTS*

Abstract

ABSTRACT The infrared spectra of a series of neutral bifunctional extractants were examined. The carbonyl and phosphoryl stretching regions were monitored for changes as nitric or hydrocloric acid was extracted and as Nd(III) or Sm(III) was extracted. It was found that the phosphoryl group is the primary site of extraction as was predicted from solvent extraction measurements. Upon heavy loading of the metal ion in the organic phase, the extractant OφD(iB)CMP0 (octyl(phenyl)-diisobutylcarbamoylmethylphosphine oxide) can behave as a bidentate ligand as does the analogous di-hexyl-N,N-diethylcarbamoylmethylphosphonate solid state complex. The tendency for the carbonyl oxygen to form a bond directly to the metal ion is enhanced in chloride media at low acidity. The spectra of mixtures of 0φD(iB)CMP0 with the phase modifier TBP indicate no interaction between the two extractants and TBP does not appear to be part of the primary metal-extractant complex.