Solvent extraction of neptunium(IV) from nitric acid solutions by sulphoxides and their mixtures

Studies have been performed on the liquid-liquid extraction of neptunium from nitric acid solutions by di-n-hexylsulphoxide (DHSO) di-no-octylsulphoxide (DOSO) and di-iso-amylsulphoxide (DISO) and their mixtures over a wide range of conditions. At a given strength of the extractant, extraction of Np(IV) increases initially rapidly with increase in the acid concentration; at high acidities, above 8M HNO₃, the extraction decreases. Under otherwise identical conditions, extraction increases with an increase in the extractant concentration. The species extracted would appear to be Np(NO₃)₄·2(R₂SO). A mixture of two extractants extracts more than the sum of the extractions due to the individual components at concentrations corresponding to those of the mixture. After loading the organic phase with uranium(VI), extractability of Np(IV) becomes considerably lower. The diminution in extraction with increase in temperature is small. A comparison of the extraction behaviour of Np(IV) with those of Pu(IV), U(VI) and some associated fission products has been made.     

Extraction of Nitric Acid and Np(IV) by some aliphatic ketones and alcohols

The extraction behaviour of HNO₃ and Np(IV) from aqueous nitrate solutions with some aliphatic alcohols and ketones using hexane, carbon tetrachloride, benzene and chloroform as diluents was studied. The acid concentration in the aqueous phase varied from 0.25 to 10 M and that of the extractant in the organic phase varied from 0.5 M to the undiluted fraction. In the alcohol systems, solutions of the same alcohol in the diluents CCl₄ and CHCl₃ showed similar capacity for acid extraction, and also in the same diluents, solutions of diisopropyl and diisobutyl alcohol showed similar capacity for extraction. Extraction of Np(IV) with the different ketones and alcohols used follow the same pattern as HNO₃.     

Extraction chemistry of uranyl nitrate and nitric acid in high concentration systems

HNO₃ is extracted in significant quantities by uranyl nitrate solvates with different extractants: TBP (tributyl phosphate), TOPO (trioctyl phosphine oxide) and TDA (tetradecyl ammonium). The effect of diluent nature is not observed on extracting HNO₃ and TBP saturated by uranium at equilibrium with its salt using the diluents (CCl₄, C₆H₅Cl, C₁₂H₂₆, CHCl₃) which are less polar than UO₂(NO₃)₂(TBP)₂. HNO₃ occurs in organic phase as undissociated form and its state is similar to pure anhydrous HNO₃. Solvates of TBP and TDA with uranyl nitrate dissolve HNO₃ without displacement of uranium from organic phase.     

Darstellung und Charakterisierung der Fulleren-Kokristallisate C60 · 12 C6H12, C70 · 12 C6H12, C60 · 12 CCl4, C60 · 2 CHBr3, C60 · 2 CHCl3, C60 · 2 H2CCl2

Synthesis and Characterization of the Fullerene Co-Crystals C₆₀ · 12 C₆H₁₂, C₇₀ · 12 C₆H₁₂, C₆₀ · 12 CCl₄, C₆₀ · 2CHBr₃, C₆₀ · 2CHCl₃, C₆₀ · 2H₂CCl₂ By crystallization of fullerenes from non-polar solvents (C₆H₁₂, CCl₄, CHBr₃, CHCl₃, H₂CCl₂) compounds of the following compositions were obtained: C₆₀ · 12C₆H₁₂, C₇₀ · 12C₆H₁₂, C₆₀ · 12CCl₄, C₆₀ · 2CHCl₃, C₆₀ · 2CHBr₃ and C₆₀ · 2H₂CCl₂. Lattice parameters have been determined by X-ray diffraction of powder samples; according to single-crystal examinations on C₆₀ · 12C₆H₁₂, C₆₀ · 12CCl₄ and C₆₀ · 2CHBr₃ the fullerene is orientationally disordered. C₆₀ · 12C₆H₁₂, cubic, a = 28.167(1) Å; C₇₀ · 12C₆H₁₂, cubic, a = 28.608(2) Å; C₆₀ · 12CCl₄, cubic, a = 27.42(1) Å; C₆₀ · 2CHBr₃, hexagonal, a = 10.212(1), c = 10.209(1) Å; C₆₀ · 2CHCl₃, hexagonal, a = 10.08(1), c = 10.11(2) Å; C₆₀ · 2H₂CCl₂, tetragonal, a = 16.400(1) Å, c = 11.645(7) Å.     

Solvent extraction behaviour of iodine and bromine in aqueous-organic systems,analogy with radioactive decay

The extraction of iodine and bromine under various conditions from their saturated aqueous solutions by CCl₄, C₆H₆ and o-xylene has been studied. The data obtained from the experiments carried out at various temperatures, for H₂O(I₂)−CCl₄ and H₂O(I₂)−C₆H₆ systems, exhibit an Arrhenius behaviour. The overall activation energy calculated for the extraction in the H₂O(I₂)−CCl₄ system, 650±50 cal·mol⁻¹ is lower than that of H₂O(I₂)−C₆H₆, 3600±300 cal·mol⁻¹. The use of the solubility parameter for the interpretation of the data in the extraction of iodine is investigated. The data obtained in multiple extractions are treated by using the analogy between extraction and radioactive decay. The half number of extraction for each system is determined. The complex curves obtained in the H₂O(I₂)−CCl₄ and H₂O(I₂) −Br₂)−CCl₄ systems are resolved into two components.     

Extraction and thermodynamic behavior of U(VI) and Th(IV) from nitric acid solution with tri-isoamyl phosphate

The extraction behavior of U(VI) and Th(IV) with tri-isoamyl phosphate–kerosene (TiAP–KO) from nitric acid medium was investigated in detail using the batch extraction method as a function of aqueous-phase acidity, TiAP concentration and temperature, then the thermodynamic parameters associated with the extraction were derived by the second-law method. It could be noted that the distribution ratios of U(VI) or Th(IV) increased with increasing HNO₃ concentration until 6 or 5 M from 0.1 M. However, a good separation factor (D _U(VI)/D _Th(IV)) of 88.25 was achieved at 6 M HNO₃, and the stripping of U(VI) from TiAP–KO with deionized water or diluted nitric acid was easier than that of Th(IV). The probable extracted species were deduced by log D-log c plot at different temperatures as UO₂(NO₃)₂·(TiAP)_(1–2) and Th(NO₃)₄·(TiAP)_(2–3), respectively. Additionally, △H, △G and △S for the extraction of U(VI) and Th(IV) revealed that the extraction of U(VI) by TiAP was an exothermic process and was counteracted by entropy change, while the extraction of Th(IV) was an endothermic process and was driven by entropy change.     

SystEme quasi ternaire H2O-Zn(NO3)2·6H2O-NH4NO3 II. les Isothermes 0; 15 et 20°C

The solid-liquid equilibria of the quasi ternary system H₂O-Zn(NO₃)₂·6H₂O-NH₄NO₃ were studied by using a synthetic method based on conductivity measurements. Three isotherms were established at 0, 15 and 20°C, and the stable solid phases which appear are: NH₄NO₃ IV, Zn(NO₃)₂·6 H₂O a and Zn(NO₃)₂·6 H₂O β. This revised version was published online in July 2006 with corrections to the Cover Date.     

LIX 84 as an extractant for throium(IV), uranium(VI) and molybdenum(VI)

The extraction order of Th(IV), U(VI) and Mo(VI) based on pH_0.5 values is Mo(VI)>U(VI)>Th(IV). Quantitative extraction has been observed for U(VI) by mixture of 10% (v/v) LIX 84 and 0.1M dibenzoylmethane at pH 4.2 and by mixture of 10% LIX 84 and 0.05M HTTA in the pH range 5.5–7.3 and for Mo(VI) by 10% LIX 84 from chloride media at pH 1.5. The order of extraction of Mo(VI) from 1N acid solutions is HCl>H₂SO₄>HNO₃>HClO₄ and extraction decreases very rapidly with increase in the concentration of HCl as compared to that from H₂SO₄, HNO₃ and HClO₄ acid solutions. The diluents C₆H₆, CCl₄ and CHCl₂ are found to be superior ton-butyl alcohol and isoamyl alcohol for extraction of Mo(VI). Influence of concentration of different anions on the extraction of U(VI) and Mo(VI) has been studied. Very little extraction has been observed in case of Th(IV) by LIX 84 or its mixtures with other chelating extractants or neutral donors.     

Darstellung und Charakterisierung von Phthalocyanin-π-Kation-Radikalen von H+, Mg2+ und Cu2+

Preparation und Characterization of Phthalocyanine-π-Cation-Radicals of H⁺, Mg²⁺, and Cu²⁺ The preparation of phthalocyanine-π-cation-radicals (Pc(?1)) of H⁺, Mg²⁺, Cu²⁺ is described. MgClPc(?1) and Cu(NO₃)Pc(?1) · HNO₃ are isolated as stoichiometrically pure, stable redbrown solids. Contrary to the phthalocyanines(?2) (Pc(?2)) these are very soluble with redviolet colour in organic solvents in the presence of R? COOH (R ? H, CF₃, CCl₃). The electronic absorption absorption spectra (UV-VIS) are remarkably solvent-dependent. This solvent effect is due to a reversible radical association. Monomeric radical species exist in nonpolar (CH₂Cl₂), dimeric in polar solvents (CH₃NO₂, C₂H₅OH). The UV-VIS, infrared (IR), and resonance-raman (RR) spectra of MgClPc(?1) and Cu(NO₃)Pc(?1) · HNO₃ are discussed and compared with the analogoues spectra of MgPc(?2) · 2 H₂O and MgPc(?2) · HCl. Although there are only minor differences in the chemical composition and the electronic structure the spectroscopic data vary significantly for every complex. Especially the IR spectrum is suitable for a quick demonstration of the π-cation-radicals. The diagnostic bands are at ca. 1350 and 1450 cm^?1.     

Hydro­gen bonding in proton‐transfer compounds of 5‐sulfosalicylic acid with bicyclic heteroaromatic Lewis bases

The crystal structures of quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate trihydrate, C₉H₈N⁺·C₇H₅O₆S⁻·3H₂O, (I), 8‐hydroxy­quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate monohydrate, C₉H₈NO⁺·C₇H₅O₆S⁻·H₂O, (II), 8‐amino­quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate dihydrate, C₉H₉N₂⁺·C₇H₅O₆S⁻·2H₂O, (III), and 2‐carboxy­quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate quinolinium‐2‐carboxylate, C₁₀H₈NO₂⁺·C₇H₅O₆S⁻·C₁₀H₇NO₂, (IV), four proton‐transfer compounds of 5‐sulfosalicylic acid with bicyclic heteroaromatic Lewis bases, reveal in each the presence of variously hydrogen‐bonded polymers. In only one of these compounds, viz. (II), is the protonated quinolinium group involved in a direct primary N⁺—H⋯O(sulfonate) hydrogen‐bonding interaction, while in the other hydrates, viz. (I) and (III), the water mol­ecules participate in the primary intermediate interaction. The quinaldic acid (quinoline‐2‐carboxylic acid) adduct, (IV), exhibits cation–cation and anion–adduct hydrogen bonding but no direct formal heteromolecular interaction other than a number of weak cation–anion and cation–adduct π–π stacking associations. In all other compounds, secondary interactions give rise to network polymer structures.     

Determination of americium-243 through its daughter product neptunium-239

The extraction of Np(IV), Zr, Nb, Cs, Ce(III) and Am(III) from nitric acid solutions containing oxalate and phosphate ions by solutions of 1-phenyl-3-methyl-4-benzoylpyrazolon-5 (PMBP) and tri-n-butyl phosphate (TBP) in benzene has been investigated. A solution 0.1M in respect to PMBP and 0.25M in respect to TBP was found to extract 99% of neptunium from aqueous solutions 1M in respect to H₃PO₄ and 0.5M in respect to HNO₃. Under these conditions, the extraction of the other investigated elements does not exceed 0.1%. Based on this finding, a procedure was developed to determine²⁴³Am through its daughter product²³⁹Np in solutions containing large quantities of curium and its fission products. The sensitivity of the procedure is 1·10⁻⁷ mg of²⁴³Am in the sample. The²⁴³Am content is obtained by calculation from measurements of the γ-activity of the extracted²³⁹Np. The purification ratio of²³⁹Np is∼10⁵ from Zr, Nb and Ru, ∼10⁸ from Ce and Cm and >10¹² from Cs.     

Thermal studies on thorium(IV) complexes of 1-butyl-1-methylpiperazinium iodide

Thorium(IV) complexes of the type Th(NO₃)₄·3L·2C₂H₅OH, Th(SCN)₄·L·C₂H₅OH and Th(SO₄)₂·2L·2C₂H₅OH (L=1-butyl-1-methylpiperazinium iodide(I) have been synthesised. From thermogravimetric (TG) curves, the decomposition pattern of the compounds has been analysed. The order, activation energy and apparent activation entropy of the thermal decomposition reaction have been elucidated. The heat of reaction has been calculated from differential thermal analysis (DTA) studies.     

Polysulfonylamine. XLVI Molekülkomplexe von Di(organosulfonyl)aminen mit Dimethylsulfoxid und Triphenylphosphinoxid. Röntgenstrukturanalyse von Di(4-fluorbenzolsulfonyl)amin-Dimethylsulfoxid(2/1)

Polysulfonyl Amines. XLVI. Molecular Adducts of Di(organosulfonyl)amines with Dimethyl Sulfoxide and Triphenylphosphine Oxide. X-Ray Structure Determination of Di(4-fluorobenzenesulfonyl)amine-Dimethyl Sulfoxide(2/1) From equimolar solutions of the respective components in CH₂Cl₂/petroleum ether, the following crystalline addition compounds were obtained: (X? C₆H₄SO₂)₂NH …? OS(CH₃)₂, where X = H, 4? CH₃, 4? Cl, 4? Br, 4? I, 4? NO₂ or 3? NO₂; [(4? F? C₆H₄SO₂)₂NH]₂ · (OS(CH)₃)₂ ( 8 ); (4? I? C₆H₄SO₂)₂NH · OP(C₆H₅)₃. A (2/1) complex of (4? F? C₆H₄SO₂)₂NH with OP(C₆H₅)₃ could not be isolated. The solid-state structure of the (2/1) compound 8 is compared with the known structure of the (1/1) complex (CH₃SO₂)₂NH · OS(CH₃)₂. The crystallographic data for 8 at ?95°C are: monoclinic, space group C2/c, a = 2 369.9(13), b = 1 006.8(4), c = 2 772.6(13) pm, β = 110.71(4)°, U = 6.187 nm³, Z = 8. Two N? H …? O hydrogen bonds with N …? O 275 and 280 pm connect the disulfonylamine molecules with the dimethyl sulfoxide molecule. The O atom of the latter has a trigonal-planar environment consisting of the S atom and the two hydrogen bond H atoms.     

Liquid-liquid extraction of molybdenum(VI) and uranium(VI) by LIX 622

The order of extraction of Mo(VI) from 1M acid solutions by 5% (v/v) LIX 622 (HL) in benzene is HCl>HNO₃>HClO₄>H₂SO₄, and extraction decreases with increasing concentration of HCl and H₂SO₄, and increases slightly with increasing concentration of HNO₃ and HClO₄. The extracted species is shown to be MoO₂L₂ as established by IR data of organic extracts and the extracted species in the solid form. Extraction is almost quantitative at and above 10% LIX 622, and is found to be independent of [Mo(VI)] in the range of 10^–4 to 10^–3 M. The diluents CCl₄, CHCl₃ and C₆H₆ are found to be superior to solvents of high dielectric constant for extraction of Mo(VI). Extraction of uranium(VI) by 10% (v/v) LIX 622 in benzene was found to increase with increasing equilibrium pH (3.0 to 6.0), and becomes quantitative at pH 5.9. Tributyl phosphate acts as a modifier up to 2% (v/v). Thorium(IV) is almost not extracted by LIX 622 or its mixture. Separation of Mo(VI) and U(VI) is feasible.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 52. Darstellung,Charakterisierung und Reaktionen von (C5H5)3Ce · THF und Na[Ce(C5H5)4] · THF

Contributions to the Chemistry of Organo Transition Metal Compounds. 52. Preparation, Characterization, and Reactions of (C₅H₅)₃Ce · THF and Na[Ce(C₅H₅)₄] · THF (C₅H₅)₃ · THF ( I ) was synthesized in a simple manner by reaction of (NH₄)₂[Ce(NO₃)₆] with C₅H₅Na. With excess C₅H₅Na the complex Na[Ce(C₅H₅)₄] · THF ( II ) could be obtained. In addition of cyclovoltammetric and polarographic measurements it was tried without success to transfer I and II into organocerium( IV ) compounds by means of different oxidizing agents. II reacts with I₂ and (C₆H₅)₃CCl forming Na[(C₅H₅)₃CeI] · THF or Na[(C₅H₅)₂CeI₂] · 4 THF and I besides of (C₆H₅)₃CCl respectively. At interaction of I with Co(acac)₃ the cobalticinium salt [(C₅H₅)₂Co][C₅H₅Ce(acac)₃] is formed. The compounds obtained were characterized by elementary analysis, hydrolysis products, magnetic moments, i.r., ¹H-n.m.r. und u.v.-vis spectra, and measurements of electric conductivity.     

Synthesis and characterization of N,N,N′,N′-tetraalkyl-4-oxaheptanediamide as extractant for extraction of uranium(VI) and thorium(IV) ions from nitric acid solution

Tridentate ligand N,N,N′,N′-tetraoctyl-4-oxaheptanediamide(TOOHA) and other three analogous diamides have been prepared and characterized by using NMR spectra and element analysis. The extraction of UO₂ ²⁺ and Th⁴⁺ with the present extractants was investigated at 293 ± 1 K from nitric acid solutions. n-Octane was found to be the most suitable diluent in the present study compared with other diluents tested. Extraction distribution ratios (D) of U(VI) and Th(IV) have been studied as a function of aqueous concentrations of HNO₃, extractant concentrations. The results indicated that U(VI) is mainly extracted as UO₂(NO₃)₂·2TOOHA. In the case of Th⁴⁺ ion, the possible compositions of extracted species in organic phase were presumed to be Th(NO₃)₄·2TOOHA and Th(NO₃)₄·3TOOHA. In addition, the influence of concentration of sodium nitrate as salting-out agent on the distribution ratio of U(VI) and Th(IV) with TOOHA was also evaluated.     

Monotonic transfer annealing kinetics associated with an oscillatory phenomenon in51Cr(III)-doped potassium chromate

Infrared absorption spectra of HNO₃ solutions in UO₂(NO₃)₂(TBP)₂ have been taken. The formation of a hydrogen bond between HNO₃ and nitrate or phosphoryl group in UO₂(NO₃)₂(TBP)₂ has been established. On extracting Pu(IV) and Np(IV) by 30% TBP-dodecane, dependence of the distribution coefficients on concentration has been found at UO₂(NO₃)₂ concentrations in the aqueous phase upwards from 0.4M. This dependence appeared in the temperature interval 0–60°C. Such effects may be caused by ordered structure of saturated uranyl nitrate solutions in TBP.     

Two‐component molecular crystals from N‐heteroaromatics and nitro­benzoic acids

Five two‐component molecular crystals, benzimidazolium 3‐nitro­benzoate, C₇H₇N₂⁺·C₇H₄NO₄^?, (I), benzimidazolium 4‐nitro­benzoate, C₇H₇N₂⁺·C₇H₄NO₄^?, (II), 1H‐benzotriazole–3‐nitro­benzoic acid (1/1), C₆H₅N₃·C₇H₅NO₄, (III), imidazol­ium 3‐nitro­benzoate, C₃H₅N₂⁺·C₇H₄NO₄^?, (IV), and imid­azolium 4‐nitro­benzoate, C₃H₅N₂⁺·C₇H₄NO₄^?, (V), were prepared with the aim of making chiral crystals. Only (I) crystallizes in a chiral space group. The mol­ecules of (I) and (II) are linked by hydrogen bonds to form 2₁ spiral chains. In (III), (IV) and (V), macrocyclic structures are formed from two acid and two base components, by an alternate arrangement of the acid and base moieties.     

Beiträge zur Organolanthanidchemie. II. Cylopentadienyllanthanid-1,3-butadien-Komplexe – Darstellung,Eigenschaften und Reaktionen

Contributions to Organolanthanide Chemistry. II. Cyclopentadienyllanthanide 1,3-Butadiene Complexes – Synthesis, Properties, and Reactions From cyclopentadienyllanthanide dihalides and “magnesium butadiene” Cp*La(C₄H₆) · MgI₂ · 3 THF ( I ), Cp*Ce(C₄H₆) · MgBr₂ · 2 THF ( II ), Cp*Nd(C₄H₆) · MgCl₂ · 2 THF ( III ), (1,3-(t-C₄H₉)₂C₅H₃)Nd(C₄H₆) · MgCl₂ · 2 THF ( IV ), CpEr(C₄H₆) · MgCl₂ · 2 THF ( V ) and (1,3-(t-C₄H₉)₂C₅H₃)Lu(C₄H₆) · MgCl₂ · 2 THF ( VI ) were obtained as highly air sensitive complexes which react easily with proton active compounds and molecules with multible bonds. The reaction products with diphenylamine and carbon dioxide Cp*Nd(NPh₂)₂ · NHPh₂ ( VII ) and Cp*Ce(O₂CC₄H₆CO₂) ( VIII ) are discribed. I–VIII were characterized by elementary analysis, i.r., ¹H and ¹³C n.m.r., and EI-MS spectra.     

Complexing between orthoperiodic acid and periodate ion in nitric acid solutions

Preparative synthesis techniques have been developed for four complex salts (Rb[H₄IO₆ · H₅IO₆], Cs[H₄IO₆ · H₅IO₆], Cs[H₄IO₆ · H₅IO₆ · 0.5H₂O], and 2CsNO₃ · HNO₃ · H₅IO₆). In the Cs(Rb)NO₃-H₅IO₆-HNO₃-H₂O systems, the starting component ratios, temperature schedules, and solvent-evaporation (H₂O + HNO₃) parameters have been determined to ensure the crystallization of the said compounds in individual states. For complex 2CsNO₃ · HNO₃ · H₅IO₆, solid-phase synthesis has also been developed. Highly water-sensitive Cs[H₄IO₆ · H₅IO₆] in the presence of water vapor converts to Cs[H₄IO₆ · H₅IO₆ · 0.5H₂O].