22541-44-2Relevant articles and documents
Crown ethers as actinide extractants in acidic aqueous biphasic systems: Partitioning behavior in solution and crystallographic analyses of the solid state
Rogers,Bauer,Bond
, p. 305 - 312 (1994)
The partitioning behavior of UO22+, Pu4+, Th4+, and Am3+ has been investigated in aqueous biphasic systems formed by the addition of polyethylene glycol of average molecular weight 2000 (PEG-2000) and (NH4)2SO4. Water-soluble crown ethers 18-crown-6 and 15-crown-5 have been utilized as extractants. A positive correlation has been observed between crown ether concentration and metal ion partitioning with DAn decreasing in the order UO22+>Pu4+>Th4+>Am3+. A distribution ratio above unity, however, has only been observed for UO22+ at very high (1.25 M) concentrations of 18-crown-6. In general the distribution ratios for 15-crown-5 are all lower. Matrix ions introduced as NH4NO3, H2SO4, or HNO3 drastically reduce the observed distribution ratios and level the extractant dependencies.
Kinetics of the reaction between plutonium(III) and xenon trioxide
Cleveland
, p. 1302 - 1305 (1967)
The kinetics of the reaction between Pu(III) and XeO3, according to the equation 6Pu(III) + XeO3 + 6H+ → 6Pu(IV) + Xe + 3H2O, have been studied in perchlorate media by following the rate of disappearance of Pu(III) spectrophotometrically at 600 mμ. The rate law for the reaction is: -d[Pu(III)]/dt = k[Pu(III)][XeO3]. The reaction rate is independent of acidity in the 0.5-2 M range. From the variation of the reaction rate with temperature, the following thermodynamic quantities of activation at 25° were calculated: ΔH? = 15.3 ± 2.1 kcal/mole; ΔF? = 20.2 ± 0.1 kcal/mole; ΔS? = -16.0 ± 6.9 eu. The mechanism of the reaction appears to involve either successive one-electron changes or a two-electron change to form a Pu(V) species other than PuO2+, which then reacts with Pu(III) to form Pu(IV).
Disproportionation of Pu(V) in aqueous HCOOH solutions
Shilov,Gogolev,Bessonov,Anan'Ev,Boltoeva
, p. 35 - 39 (2010)
The behavior of Pu(VI), Pu(V), and Pu(IV) in the HCOOH-H2O system was studied by spectrophotometry. The Pu(VI) absorption spectrum in solutions containing less than 1 mM HClO4 changes on adding HCOOH to a concentration of 0.53 M. Along with a decrease in the intensity of the absorption maximum at 830.6 nm, corresponding to an f-f transition in the Pu 2 2+ aqua ion, a new band arises with the maximum shifted to 834.5 nm. These transformations are due to formation of a Pu(VI) formate complex (1: 1). The Pu(IV) absorption spectra in HCOOH solutions vary insignificantly in going from 3.0 to 9.0 M HCOOH and are similar to the spectrum of Pu(IV) in a 0.88 M HCOOH + 0.41 M NaHCOO + 0.88 M NaClO4 solution, which indicates that the composition of the Pu(IV) formate complexes is constant. Pu(V) is unstable in HCOOH solutions and disproportionates to form Pu(VI) and Pu(IV). The reaction rate is approximately proportional to [Pu(V)]2 and grows with an increase in [HCOOH]. The reaction products affect the reaction rate: Pu(IV) accelerates the process, and Pu(VI) decelerates the consumption of Pu(V) by binding Pu(V) in a cationcation complex. The disproportionation occurs via formation of a Pu(V)-Pu(V) cation-cation complex whose thermal excitation yields an activated complex with its subsequent decomposition to Pu(VI) and Pu(IV).
Neutron resonance scattering shows specific binding of plutonium to the calcium-binding sites of the protein calmodulin and yields precise distance information
Seeger,Rokop,Palmer,Henderson,Hobart,Trewhella
, p. 5118 - 5125 (1997)
We have successfully substituted 240Pu3+ for Ca2+ in the calcium- binding protein calmodulin and used neutron resonance scattering from the bound 240Pu to demonstrate that the Pu binds specifically to the Ca2+ sites and also to measure the distance between the ion binding sites within individual domains of the protein. 240Pu has a strong nuclear resonance at 0.278 ?, and at this wavelength the coherent scattering from 240Pu is > 1000 times that of any other nucleus present in a protein. The ionic radius of Pu3+ is very similar to that of Ca2+, and hence we chose this species to substitute for Ca2+ in the protein. We identified solution conditions that stablize Pu3+ in solution at near neutral pH for 6-7 h in order to form the Pu/calmodulin complex under conditions favorable for both complex formation and maintaining the structural integrity of the protein. We collected small-angle neutron scattering data from solutions of 4(240Pu3+)·calmodulin, which contain periodic terms that are directly related to the distances between the Ca2+-binding sites. The shorter Pu-Pu distance, i.e., the average distance between the two sites within each globular domain of calmodulin, is found to be 11.8 ± 0.4 ?, in excellent agreement with the value of 11.7 ? from crystallographic determinations. This is the first use of neutron resonance scattering as a structural probe in a protein.
Improvement of precision spectrophotometric method with internal reference and its application to analysis of plutonium solutions
Stepanov,Stepanov,Nikitina,Gogoleva,Grigor'eva,Bulyanitsa,Panteleev,Pen'kin,Pevtsova,Domkin
, p. 198 - 203 (2006)
A spectrophotometric precision method with internal reference [1, 2] was applied to analysis of straight Pu solutions for certifying Pu reference materials and for studying the PuO2 solubility in the framework of developing methods for accounting and control of nuclear materials. In the context of the activities mainly concerned with certification of reference materials, a two-channel spectrophotomer and the corresponding technique were further improved in order to decrease the error of the method. This allowed the random component of the relative error of the method to be decreased from 0.1 to 0.04% at the confidence level p = 0.95 and the number of degrees of freedom f = 25. The fixed component of the error of the method was studied in relation to impurities of U, Np and corrosion products of structural materials. Also, the extent of Pu oxidation during sample preparation was studied as influenced by the fluoride ion. The revealed lack of such influence within the limits of the study indicates that the method is suitable for analysis of Pu in mixed solutions. Pleiades Publishing, Inc., 2006.
Metal corrosion studies with the fluorosulphonic acid-antimony pentafluoride superacid system
Eller, P. Gary,Kissane, Richard J.,Abney, Kent D.,Avens, Larry R.,Kinkead, Scott A.,Hanrahan, Robert J.
, p. 134 - 137 (2004)
Because of their rapid dissolution of many actinide metals and refractory oxides, superacids such as HSO3F/SbF5 have potential applications in actinide processing. However, material compatibility must first be addressed because of the highly corrosive nature of superacids. This paper describes the qualitative rates of attack of fluorosulphonic acid-antimony pentafluoride superacid on a variety of metal substrates relevant to nuclear processing. Published by Elsevier B.V.
Sonochemical redox reactions of Pu(III) and Pu(IV) in aqueous nitric solutions
Virot, Matthieu,Venault, Laurent,Moisy, Philippe,Nikitenko, Sergey I.
, p. 2567 - 2574 (2015/02/19)
The behavior of Pu(iv) and Pu(iii) was investigated in aqueous nitric solutions under ultrasound irradiation (Ar, 20 kHz). In the absence of anti-nitrous reagents, ultrasound has no effect on Pu(iv), while Pu(iii) can be rapidly oxidized to Pu(iv) due to the autocatalytic formation of HNO2 induced by HNO3 sonolysis. In the presence of anti-nitrous reagents (sulfamic acid or hydrazinium nitrate), Pu(iv) can be sonochemically reduced to Pu(iii). The reduction follows a first order reaction law and leads to a steady state where Pu(iv) and Pu(iii) coexist in solution. The reduction process is attributed to the sonochemical generation of H2O2 in solution. The kinetics attributed to the reduction of Pu(iv) are however higher than those related to the formation of H2O2 which, after several hypotheses, is explained by the sonochemical erosion of the titanium-based sonotrode. Titanium particles thereby generated can be solubilized under ultrasound and generate Ti(iii) as an intermediate species, a strong reducing agent able to react with Pu(iv).
A novel CMPO-functionalized task specific ionic liquid: Synthesis, extraction and spectroscopic investigations of actinide and lanthanide complexes
Mohapatra, Prasanta K.,Kandwal, Pankaj,Iqbal, Mudassir,Huskens, Jurriaan,Murali, Mallekav S.,Verboom, Willem
supporting information, p. 4343 - 4347 (2013/04/23)
A novel CMPO (carbamoylmethylphosphine oxide) based task specific ionic liquid (TSIL) with an NTf2- counter anion was synthesized and evaluated for actinide/lanthanide extraction from acidic feed solutions using several room temperature ionic liquids (RTILs). The extraction data were compared with those obtained with CMPO in the same set of RTILs and also in the molecular diluent, n-dodecane. The extracted species were analyzed by the conventional slope analysis method and the extraction followed an ion-exchange mechanism. The nature of bonding in the extracted complexes was investigated by various spectroscopic techniques such as FT-IR and UV-visible spectroscopy. The Royal Society of Chemistry 2013.
Reduction of Pu(IV) and Np(VI) with carbohydrazide in nitric acid solution
Volk,Marchenko,Dvoeglazov,Alekseenko,Bychkov,Pavlyukevich,Bondin,D'Yachenko
, p. 143 - 148 (2012/08/29)
The reduction of Pu(IV) and Np(VI) with carbohydrazide (NH 2NH)2CO in 1-6 M HNO3 solutions was studied. The Pu(IV) reduction is described by a first-order rate equation with respect to Pu(IV). At [HNO3] ≥ 3 M, the reaction becomes reversible. The rate constants of the forward and reverse reactions were determined, and their activation energies were estimated. Neptunium(VI) is reduced to Np(V) at a high rate, whereas the subsequent reduction of Np(V) to Np(IV) is considerably slower and is catalyzed by Fe and Tc ions. The possibility of using carbohydrazide for stabilizing desired combinations of Pu and Np valence states was examined. Pleiades Publishing, Inc., 2012.
Pu(III) Oxidation with tert-Butyl Hydroperoxide in the Presence of Fe(III) as Catalyst
Koltunov, V. S.,Baranov, S. M.,Pastushchak, V. G.,Koltunov, G. V.
, p. 132 - 136 (2008/10/08)
The rate-determining step of Pu(III) oxidation with tert-butyl hydroperoxide in the presence of Fe(III) ions is reaction of Fe(2+) cations with(CH3)3COOH. The subsequent fast step is reversible oxidation of Pu(3+) cations with Fe(3+) cations. In accordance with this scheme, the rate ofPu(III) oxidation in an HNO3 solution is described by the equation -d[Pu(III)]/dt = k[Pu(III)][(CH3)3COOH][Fe(III)][HNO3]**1.5/[Pu(IV)], where k1 = 0.206+/-0.007 l**2.5*mol**-2.5*min**-1 at 26 °C and variableionic strength. The activation energy is E = 58.1+/-1.1 kJ*mol**-1.
