Advanced TALSPEAK processes are currently being investigated as a method for separating trivalent lanthanides from trivalent actinides.  These solvent extraction methods partition the lanthanides and actinides between an organic phase containing an organophosphorus extractant and an aqueous phase.  In order to effectively design these processes it is important to have insight into the interactions between the metal ions, extractant molecules, solvent and any other solute molecules that could be present.  Though NMR spectroscopy has been applied infrequently to characterize solvent extraction systems, such investigations could provide useful insights into ligand exchange reactions in the organic phase.  In this study, 31P NMR has been applied to probe the interactions between (2-ethylhexyl) phosphonic acid mono (2-ethylhexyl) ester (HEH[EHP]) and lanthanide(III) cations.  Fresh insights into complex formation reactions in the apolar organic phase have been developed.  Through investigations at variable temperatures, exchange rates and activation parameters can be calculated using the complete band shape analysis by the Rogers and Woodbrey general equations for an uncoupled two-site exchange.  Results of investigations probing the effect of increasing the polarity of the organic phase on the ligand exchange reactions will also be reported. Work performed at Washington State University with support from the US Department of Energy, Office of Nuclear Energy, Nuclear Energy University Program (NEUP) as an element of project number DE-AC07-015ID145517.

Probing ligand exchange reactions of lanthanide-HEH[EHP] complexes in organic solvents using <sup>31</sup>P NMR spectroscopy

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Probing ligand exchange reactions of lanthanide-HEH[EHP] complexes in organic solvents using 31P NMR spectroscopy

Probing ligand exchange reactions of lanthanide-HEH[EHP] complexes in organic solvents using ³¹P NMR spectroscopy