甲酸双氧铀的红外多光子离解

本文研究了固相甲酸双氧铀[UO_2(HCOO)_2·H_2O]在TEA CO_2激光作用下的红外多光子离解。测得其中间产物为碱式甲酸双氧铀[UO_2(OH)(HCOO)·H_2O],最终的固体产物主要是八氧化三铀[U_3O_8];并提出了该反应模型。     

Preparation and thermal reactivity of some rare earth and uranyl hydrazinesulfinates and sulfite hydrazinates

Hydrazinesulfinate and sulfite hydrazinate derivatives of rare earth elements of composition Ln(N₂H₃SOO)₃(H₂O) and Ln₂(SO₃)₃(N₂H₄)_x(H₂O)_y, respectively, where Ln=La, Ce, Pr, Nd and Sm, have been prepared and characterized by chemical analysis and infrared spectra. The uranyl complexes of the composition UO₂(N₂H₃SOO)₂, UO₂(N₂H₃SOO)₂(N₂H₄) and UO₂SO₃(N₂H₄)(H₂O) have also been prepared under different reaction conditions and studied by different physicochemical techniques. Thermal properties of all these complexes have been studied by thermogravimetry, and differential scanning calorimetry. The hydrazinesulfinate derivatives of rare earth elements undergo thermal decomposition in multisteps to give the respective metal sulfate as the residue. The other series of complexes, viz., rare earth sulfite hydrazinates gave a mixture of metal sulfate and metal oxide as the end products. However, all the uranyl complexes undergo decomposition in air to give UO₂SO₃ as the final product.     

Cryoscopic Studies of the Uranyl Sulfate–Water, Uranyl Nitrate–Water, and Uranyl Nitrate–Nitric Acid–Water Systems

Freezing point lowerings of aqueous solutions of uranyl sulfate in the concentration range m 0.40 mol-kg^–1 and the activity and osmotic coefficients, which were calculated using the Pitzer equations for 2:2 electrolytes, are presented. Crystallization temperatures are reported for 0 to 13 molar nitric acid and 10–150 g uranium per liter uranyl nitrate–nitric acid–water solutions.     

Synthesis and Crystal Structure of Bis(nitrate)bis(dipiperidin-1-yl-methanone)uranyl(II)

1 INTRODUCTION The extraction chemistry of uranium is a veryimportant research field, and the new high extrac-tants of uranium have being studied for several deca-des[1, . Our interest is studying the behaviors of new 2]extractants and their st…     

Binding of uranyl ion by 2,2′-dihydroxyazobenzene attached to crosslinked polystyrenes covered with highly populated quaternary ammonium cations

2,2′-Dihydroxyazobenzene (DHAB) derivatives were attached to poly(chloromethylstyrene-co-divinylbenzene) (PCD) because of the high affinity of DHAB for uranyl ion. Chloromethyl groups of PCD were converted to quaternary ammonium ions by treating them with tertiary amines. Two strategies were adopted to improve the uranyl-binding ability of the immobilized DHAB: (1) the creation of a highly cationic microenvironment around the DHAB moieties and (2) the introduction of electron-withdrawing groups to DHAB. Capacity of the resins for uranyl uptake was measured, revealing that about 10 to 46 mg of uranium could be complexed to 1 g of the resins. Formation constants (K_f) for the uranyl complexes of the resins were determined. In the presence of ≥0.02 M bicarbonate ion at pH 8.02, log K_f values of 14.3 to 15.8 were obtained. Uranium extraction from seawater with two kinds of resins prepared in this study was carried out on the east coast of the Korean peninsula. The amount of uranium extracted from seawater was up to 150 μg/g resin. Thus, the uranium-extracting capability of the DHAB-containing polystyrene resins was improved significantly by the structural modifications. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4117–4125, 1999     

Dependence of the spectroscopic properties of pentauranylfluoride crystals on temperature in the range from 4.2 to 40 K

Using the configuration interaction model, we investigate the dependence of the shape, half-width, and position of the phononless lines (PL) in absorption and luminescence spectra of K₃UO₂F₅ and Rb₃UO₂F₅ crystals in the region 4.2–40 K. It is established that a Stokes shift in combining electron states leads to a nonsymmetric distortion in the Gauss shape of thePL. The temperature broadening of the PL is mainly associated with a change in the population of the initial states of oscillators (of the ground state for absorption and the 1 st excited state for luminescence), while a shift in maxima of the PL is caused by the forbidden 1 st electron transitions in complex uranyl compounds and is determined by the nonlinear electron-phonon interaction. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 824–827, November–December, 1999.     

二硝酸根(N, N, N'', N''－四正丁基丙二酰胺)合铀酰(Ⅱ)配合物的合成和结构

配合物[UO₂(Bu₂NCOCH₂CONBu₂)(NO₃)₂]晶体属单斜晶系,P2₁/c空间群,a=10.744(2),b=13.229(5),c=20.011(8)β,β=99.21(3)°,V=2808(2)β³,D_c=1.07g·cm^-3,Z=4,配合物分子中具有直线结构的铀酰离子由六个氧原子配位,其中四个来自硝酸根,另外两个来自羰基,形成平面六角形,六角形的平面与铀酰离子的直线垂直,两个硝酸根处于相邻位置.     

Ion‐exchange resins. III. Functionalization–morphology correlations in the synthesis of some macroporous,strong basic anion exchangers and uranium‐sorption properties evaluation

The synthesis and characterization of a series of macroporous, strong basic anion exchangers (SBAEs), with an average pore radius higher than 50 nm, and the evaluation of their sorption properties for uranyl chlorocomplexes from HCl solutions are reported. Finely divided macroporous styrene–divinylbenzene (S–DVB) copolymers with a narrow distribution of beads sizes, diameters within the range of 90–200 μm, were prepared for this purpose with 2‐ethyl‐1‐hexanol as a porogen, at a high dilution of monomers (D ≥ 0.55 mL/mL). Chloromethyl groups were introduced with (CH₂O)_n/Me₃SiCl as a chloromethylation agent in the presence of a Lewis acid as a catalyst (TiCl₄, SnCl₄, and FeCl₃) in CHCl₃ as a reaction medium. SnCl₄ and FeCl₃ gave comparable chloromethylation degrees in the same reaction conditions. TiCl₄ was not efficient as a catalyst in the chloromethylation with this reagent. Diethyl‐2‐hydroxyethylamine was used as a tertiary amine to prepare SBAEs. Structural and morphological characteristics were determined after every functionalization step of the macroporous network. Both the chloromethylation, in the presence of FeCl₃ as a catalyst, and the amination reactions determined a significant decrease of the pore volume, in the whole range of the nominal crosslinking degree, comparative with the starting copolymer. The specific surface area and the average pore radius varied in a different way as a function of the nominal crosslinking degree. Thus, the specific surface area increased and the average pore radius decreased after chloromethylation and amination for copolymers with a DVB content lower than 10 wt %. Small decreases of the specific surface area and the average pore radius were observed after chloromethylation and amination reactions for copolymers with a DVB content higher than 10 wt %. SBAEs were also characterized by thermogravimetric analysis and sorption capacity for uranyl chlorocomplexes. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2451–2461, 2004     

Vibrational Spectra of Oxalate Complexes of Uranyl with Neutral Organophosphorus Ligands

The vibrational spectra of a number of polycrystalline oxalate complexes of uranyl with neutral organophosphorus ligands have been investigated. Based on the empirical formula of the compounds, the results of the analysis of experimental IR absorption spectra and Raman spectra, and the data of calculation of the frequencies and forms of normal vibrations, a possible structure of the complexes is suggested. A fragment of the structure of any member of this series can be represented as a polymer chain formed by bridge C₂O₄ ^2– groups. The coordination sphere of uranyl is complemented by the oxygen of phosphine oxide, and the hydrocarbon radical is positioned on either side of the polymer chain.     

Ligand Exchange and Nature of Luminescence Centers in the Crystals of Uranyl Nitrates and Perchlorates

We obtained complexes of uranyl nitrates and uranyl perchlorates with neutral ligands in crystalline and amorphous states and also with variable composition (as regards both water and the quantity of acid ligands entering into the first coordination sphere of UO₂ ²⁺). We studied their luminescence spectra at T = 77 K. Correlation between the frequencies of electronic and vibronic transitions and the donor numbers of neutral ligands has been established. The possible ways of replacing neutral ligands in the first coordination sphere of UO₂ ²⁺ have been analyzed as well as the composition and structure of the complex systems formed in this case.