Lipophilic ternary complexes in liquid-liquid extraction of trivalent lanthanides

摘要

The formation of ternary complexes between lanthanidc ions [Nd(III) or Eu(III)] octyl(phcnyl)-N,N-diisobutyl-carbamoy!methylphosphinc oxide (CMPO) and bis (2-ethylhcxyl) phosphoric acid (HDEHP) was probed by liquid-liquid extraction and spectroscopic techniques. Equilibrium modeling of data for the extraction of Nd(III) or Eu(III) from lactic-acid media into n-dodecane solutions of CMPO and HDEHP indicates the predominant extracted species are of the type [Ln(AHA)_2(A)J and [Ln(CMPO)(AHA)_2(A)]. where Ln=Nd or Eu and A represents the DEHP anion. FTIR (for both Eu and Nd) and visible spectrophotometry (in the case of Nd) indicate the formation of the [Ln(CMPO)(A)_3] complexes when CMPO is added to n-dodecane solutions of the LnA, compounds Both techniques indicate a stronger propensity of CMPO to complex Nd(IlI) versus Eu(III)