[en] Preparation and use of tetra-C-alkyl cobalt dicarbollide for extraction of cesium and strontium into hydrocarbon solvents. Tetra-C-alkyl derivatives of cobalt dicarbollide, Co(C₂R₂B₉H₉)₂^-(CoB₂R₄^-; R=CH₃ and C₆H₁₃) are demonstrated to be significant cesium and strontium extractants from acidic and alkaline solutions into non-toxic organic solvent systems. Extractions using mesitylene and diethylbenzene are compared to those with nitrobenzene as the organic phase. CoB₂-hexyl₄^- in diethylbenzene shows improved selectivity (10⁴) for Cs over Na in acidic solution. In dilute alkaline solution, CoB₂-hexyl₄^- extracts Cs less efficiently, but more effectively removes Sr from higher base concentrations. A general synthesis of tetra-C-alkyl cobalt dicarbollides is described. 6 figs

[en] Both civilian and defense related waste must be processed with a strategy for dealing with Tc. One solution is to remove the Tc from the waste steam and transmute the Tc to stable Ru in either a reactor or an accelerator. Before any processing of waste streams can be performed (even if transmutation is not performed) the separations chemistry from the spent fuels or the stored wastes containing Tc must be developed. This report details some of the separation schemes possible for the separation of Tc and Ru, which include the baseline ion exchange process of Roberts, Smith and Wheelwright, ozonolysis, filtration, magnetic separation, solvent extraction, electrodeposition, fluorination, and pyrolysis. 5 figs, 4 refs

[en] Preparation and use is described for polymeric materials containing hydrophobic anions and plasticizers for extraction of cesium and strontium. The use of polymeric materials containing plasticizers which are solvents for hydrophobic anions such as derivatives of cobalt dicarbollide or tetraphenylborate which are capable of extracting cesium and strontium ions from aqueous solutions in contact with the polymeric materials, is described. The polymeric material may also include a synergistic agent for a given ion like polyethylene glycol or a crown ether, for removal of radioactive isotopes of cesium and strontium from solutions of diverse composition and, in particular, for solutions containing large excess of sodium nitrate

[en] The molecular structure of ThBr₄(DME)₂(DME = 1,2-dimethoxyethane), the first structurally characterized thorium complex containing a simple bidentate ether ligand, is described. The eight-coordinate complex presents a distorted dodecahedral geometry, with Th-Br and Th-O bond lengths in the ranges 2.8516(13)-2.8712(13) A and 2.564(8)-2.620(8) A, respectively. ThBr₄(DME)₂ is monoclinic, space group P2₁/n, a = 7.672(1), b = 14.581(1), c = 15.847(2) angstrom, β = 102.24(1)degree, V = 1732.4(3) A³, and Z = 4

[en] Preparation and use is described for polymeric materials containing hydrophobic anions and plasticizers for extraction of cesium and strontium. The use of polymeric materials containing plasticizers which are solvents for hydrophobic anions such as derivatives of cobalt dicarbollide or tetraphenylborate which are capable of extracting cesium and strontium ions from aqueous solutions in contact with the polymeric materials, is described. The polymeric material may also include a synergistic agent for a given ion like polyethylene glycol or a crown ether, for removal of radioactive isotopes of cesium and strontium from solutions of diverse composition and, in particular, for solutions containing large excess of sodium nitrate

[en] The superacid system HF/SbF₅ is extraordinarily effective for total dissolution of actinide and lanthanide ceramic oxides, fluorides, and metals. Optical or gamma spectroscopy can be used directly on the solutions. Evaporation of the HF/SbF₅ solvent under vacuum leaves a residue which is easily dissolved by ordinary mineral acids. The resulting aqueous solutions are readily amenable to conventional analytical methods

[en] Transport behavior of monovalent and divalent solutes across mesoporous Anopore γ-alumina membranes was investigated as a function of pore diameter, pH, ionic strength, and nature of the salt or complexing species in solutions. Radiotracer ¹³⁷Cs, ⁸⁵Sr, ²²Na, and ⁴⁵Ca were present in the feed solutions at very low concentrations, ranging from 10^-9 to 10^-12M and total salt concentrations from 0.1 to 10^-4M. The divalent cations Ca²⁺ and Sr²⁺ exhibit lower diffusion rates (3--7 times slower) than the monovalent cations Cs⁺ and Na⁺ for membranes with 20 nm diameter pores. Differences between monovalent and divalent cation diffusion rates for the membranes can be explained in terms of a Donnan exclusion effect from the positively charged alumina surface. The rate of Sr²⁺ transport across the 20 nm alumina membranes was greatly increased by raising the pH (reducing the membrane surface charge) from 5 to 8 for both the feed and receive sides. Increased ionic strengths and the addition of complexing agents or specific salt solutions also facilitated divalent ion transport. Diffusion coefficients for divalent cations increased 3-fold for the 100 nm pore diameter membranes

[en] Polymers containing the cobalt dicarbollide anion, [Co(C₂B₉H₁₀)₂], in the main chain have potential application as cation exchange materials for the selective removal of 137Cs⁺ and ⁹⁰Sr⁺² from nuclear wastes. Our research is directed at the synthesis of complex [Co(LiC₂B₉H₁₀)₂], as a starting material. Reaction of [Co(LiC₂B₉H₁₀)₂] with CO₂/H⁺ in the thf gives the dicarboxylic acid complex, [Co(C₂B₉H₁₀)₂(COOH)₂]. Two methods for the conversion of the dicarboxylic acid to a polyamide derivative, [Li]_n[OC(C₂B₉H₁₀)Co(C₂B₉H₁₀)CONH(CH₂)₆NH]_n have been investigated. The spectroscopic properties of the monomers as well as the characterization of the polyamide by light scattering photometry and GPC methods will be discussed. Reaction of the dialcohol monomer, [Co(C₂B₉H₁₀)₂(C₂H₄OH)₂], formed by reaction of [Co(LiC₂B₉H₁₀)₂] with CH₂OCH₂/H⁺ in thf, with isocyanates provides entry into polyurethane chemistry and will also be discussed

[en] The reaction chemistry of ⁹⁹Tc, as LiTcO₄, and ¹⁰⁶Ru, as RuO₄, has been investigated. Both of these isotopes are produced in significant quantities by the fission of either plutonium or uranium and represent a great challenge to the partitioning of nuclear waste. One proposal for rendering technetium to an environmentally benign element is the transmutation of technetium to ruthenium by reaction of ⁹⁹Tc with thermal neutrons to form stable ¹⁰⁰Ru. Los Alamos is currently investigating this possibility with the aid of an accelerator, (i.e., Accelerator Transmutation of Waste, ATW). Thus, the authors have initiated an investigation of the separation of ruthenium from technetium by means of reaction with ozone. The results of this investigation are reported including separation factors

[en] Salts of the OTeF₅^- anion were investigated by ir and Raman spectroscopy and by x-ray crystallography. Experimental results were compared with ab initio Hartree-Fock calculations on the OTeF₅ radical, Na⁺OTeF₅^-, and the singlet and triplet states of the free OTeF₅^-. The compound [(PS)H⁺][OTeF₅^-] was examined by single-crystal X-ray crystallography ((PS)H⁺ = protonated 1,8-bis(dimethylamino)naphthalene): bar P1, a = 8.241 (1) angstrom, b = 8.768 (2) angstrom, c = 12.591 (3) angstrom, α = 74.08 (2)degree, β = 78.00 (2)degree, γ = 80.23 (2)degree, Z = 2, T = -106 degree C. Unlike other salts of the OTeF₅^- anion, [(PS)H⁺][OTeF₅^-] did not exhibit any O/F disorder. Since the spectroscopic data for [(PS)H⁺][OTeF₅^-] closely matched those of [N(n-Bu)₄⁺][OTeF₅^-], it was concluded that this structure contains the best approximation of the structure of the free OTeF₅^- anion. The librationally corrected results are Te-O = 1.803 angstrom, Te-F_ax = 1.872 angstrom, Te-F_eq = 1.870 angstrom (average), and O-Te-F_eq = 95.2 degrees (average). A normal-coordinate analysis of OTeF₅^- was carried out by using this geometry and spectroscopic data for the ¹⁶O and ¹⁸O equivalents of [N(n-Bu)₄⁺][OteF₅^-]. 41 references, 5 figures, 8 tables