Acknowledgements Jamie Warburton, Cynthia Gong, Tom O’Dou and Trevor Low

1. Application of Formohydroxamic Acid in Nuclear Processing: Synthesis and Complexation with Technetium 99 Amber Wright, Keri Campbell, Edward Mausolf, Frederic Poineau, Patricia Paviet-Hartmann Abstract Acetohydroxamic acid (AHA) is an organic ligand planned for use in the UREX process. It reduces neptunium and plutonium, and the resultant hydrophilic complexes are separated from uranium by extraction with tributylphosphate (TBP) in a hydrocarbon diluent. Hydroxamic acids undergo hydrolysis to hydroxylamine and the pertinent carboxylic acid. The reported reduction potentials of AHA and pertechnetate (TcO4-) indicate that it may be possible for AHA to reduce technetium, altering its fate in the fuel cycle. At UNLV, it has been demonstrated that TcO4- undergoes reductive nitrosylation by AHA under a variety of conditions. The resulting divalent technetium is complexed by AHA to form the pseudo-octahedral trans-aquonitrosyl (diacetohydroxamic)-technetium(II) complex ([TcII(NO)(AHA)2H2O]+). During recent discussions of the UREX process, it has been proposed to replace AHA by formohydroxamic acid (FHA). Preliminary results on the synthesis of FHA and its complex formation with Tc are presented along with the characterization of FHA crystals achieved by NMR and IR spectroscopy. The complex formation between technetium and FHA has been studied by UV-visible spectrophotometry and compared to the complexation of AHA with Tc. Synthesis/Characterization of FHA Complexation of FHA with Tc Two experiments were conducted to investigate the complexation of FHA with Tc and to compare with previous data on AHA. The first involved the elution of Tc from a Reillex HP anion exchange resin. The column was pre-equilibrated with 0.01 M nitric acid before being loaded with 1x10-4 M ammonium pertechnetate. The elution kinetics of Tc by 1 M FHA and 1 M AHA were monitored for 24 hours by liquid scintillation counting (Fig. 4). 2 2 This study results in FHA eluting about half the amount of Tc as AHA in the same time period. This implies that FHA and AHA complex and reduce Tc(VII), but that FHA appears to be a “softer” reducing agent and ligand. Fig 1. Synthesis route for FHA Preparation of FHA was completed using a synthesis route described in literature (Fig. 1). After re-crystallization in hot acetonitrile, 1.23g of FHA crystals were collected for analysis and experiments with Tc. This provides a yield of approximately 5%. The melting point was determined to be 78-80°C, which is in agreement with the theoretical value. Further characterization was performed by IR and NMR spectroscopy (Fig. 2 and Fig. 3). These results also agree with previous spectra of FHA, implying that a pure compound was synthesized. Fig 4. Elution of TcO4- from Reillex HP resin with AHA and FHA A second experiment monitored complexation of Tc with FHA . A 3 M solution of FHA was mixed with a 3.3x10-4 M solution of ammonium pertechnetate, then nitric acid was added to make the solution 3 M HNO3. The solution (initially clear) turns yellow (Fig. 5), but does so more slowly than the AHA system. N-O The IR and NMR spectra show all the appropriate bonds for the structure of FHA. The FHA product appears to have very little to no impurities. C-N N-H str O-H b C-H b C=O (N)-O-H str Fig 6. UV-Vis Spectra of Tc-FHA complex over time Fig 2. Infrared spectrum of recovered FHA product Fig. 5 Tc-FHA in a quartz cuvette This reaction was analyzed by UV-visible spectroscopy (Fig. 6) after time periods of 85 and 3250 minutes (~50hrs). The spectra show a reduced and complexed species of Tc-FHA growing in, similar to the AHA system (Fig. 7). Acknowledgements Jamie Warburton, Cynthia Gong, Tom O’Dou and Trevor Low Fig 3. Proton and carbon NMR spectra of recovered FHA product Fig 7. Comparison of Tc-AHA and Tc-FHA UV-Vis spectra