Simulation of radioactivation and chlorination reaction behavior for Zircaloy-4 and Zirlo cladding hull wastes

Radioactivation of Zircaloy-4 (Zry-4) and Zirlo cladding hulls after 55 GWD/tU burn-up and 10 years of cooling was simulated using the ORIGEN-S code. The simulation results revealed that ¹²⁵Sb and ⁶⁰Co are major contributors of both radioactivity and decay heat in the case of the Zry-4 hulls. For the Zirlo hulls, ^93mNb and ¹²⁵Sb consisted 82.2% of radioactivity while ¹²⁵Sb and ⁶⁰Co emitted 77.9% of decay heat. Although the radioactivity between the Zry-4 (1.17 Ci for 1 kg of fresh Zry-4) and Zirlo (1.38 Ci for 1 kg of fresh Zirlo) hulls was not significantly different, decay heat of the activated Zry-4 hulls (8.58 mW) was much larger than 1.62 mW of the activated Zirlo hulls. This gap might have come from the different major constituents of Zry-4 (Zr, Sn, Fe, and Cr) and Zirlo (Zr, Sn, Nb, and Fe) resulting in different radioactive nuclides after radioactivation. Chlorination reaction behavior of the activated Zry-4 and Zirlo hulls was performed using the HSC chemistry code. Constituents of recovered ZrCl₄ were investigated via changes of Gibbs free energy and boiling points of resulting chlorides. The calculation results suggested that radioactivity and decay heat might decrease by 49.0 and 81.8%, respectively, in the ZrCl₄ recovered from the activated Zry-4 hulls. In the case of Zirlo, it was expected that radioactivity and decay heat might decrease by 11.6 and 13.0%, respectively, after the chlorination reaction. Effect of cooling time on radioactivity and decay heat was also investigated.     

Effect of chlorinating reagents on Zr recovery from Zircaloy-4 hull wastes: reaction behavior simulation by using the HSC code

Chlorination reaction behavior of Zircaloy-4 (Zry-4) was simulated by using the HSC code for three different chlorinating reagents of Cl₂, HCl, and CCl₄. Four major components (Zr, Sn, Fe, and Cr) of Zry-4 and their oxides which were produced during an oxidative decladding process were considered for the theoretical calculation. The simulation results revealed that Cl₂ might convert metallic Zr, Sn, Fe, and Cr into their chloride forms, while oxides might not react with Cl₂ at 380 °C. When HCl was employed as the chlorinating reagent, it was suggested that metallic Zr, Sn, and Cr might react with HCl while Fe and oxides might not. In the case of CCl₄, it was shown that CCl₄ could react with all of the metallic and oxide components to produce most amount of ZrCl₄ when compared with Cl₂ and HCl cases. Reaction behavior of the chlorinating reagents with residual spent nuclear fuel constituents (U₃O₈, MoO₃, Pd, BaO, Y₂O₃, SrO, Rh₂O₃, RhO₂, La₂O₃, CeO₂, and Nd₂O₃) was also performed, and it was revealed that Cl₂ and HCl might produce (PdCl₂, BaCl₂, SrCl₂, RhCl₃, LaCl₃, and NdCl₃) and (BaCl₂, YCl₃, SrCl₂, RhCl₃, LaCl₃, and NdCl₃), respectively. Although these by-products are produced, it was suggested that highly pure ZrCl₄(g) which contains FeCl₃(g) and SnCl₄(g) as impurities might be recovered when Cl₂ or HCl is employed as a chlorinating reagent because other by-products have higher boiling point than the reaction temperature of this study (380 °C). On the other hand, the theoretical calculation results showed that CCl₄ might react with all the residual spent fuel constituents to produce additional gaseous impurities of UCl₆ and MoCl₅ to reduce the purity of ZrCl₄ product.     

Ferrocene/ferrocenium ion as a catalyst for the photodecomposition of chloroform

Irradiation (λ > 320 nm) of ferrocene in chloroform causes decomposition of chloroform and the accumulation of HCl, CCl₃OOH, and C₂Cl₆. This appears to occur initially through a cycle in which (a) ferrocene is oxidized to ferrocenium and tetrachloroferrate ions, (b) FeCl₄ ⁻ undergoes photodissociation, and (c) ferrocenium reoxidizes the chloroferrate(II) species. On extended photolysis, the concentrations of CCl₃OOH and FeCl₄ ⁻ build up and a competing cycle in which FeCl₄ ⁻ is restored through oxidation of the chloroferrate(II) species by CCl₃OOH accelerates the decomposition rate.     

Zirconium tetrachloride revisited

Zirconium tetrachloride, ZrCl₄, is a strategic material with wide‐ranging applications. Until now, only one crystallographic study on ZrCl₄ has been reported [Krebs (1970). Z. Anorg. Allg. Chem. 378 , 263–272] and that was more than 40 years ago. The compound used for the previous determination was prepared from ZrO₂ and Cl₂–CCl₄, and single‐crystal X‐ray diffraction (SCXRD) studies on ZrCl₄ obtained from Zr metal have not yet been reported. In this context, we prepared ZrCl₄ from the reaction of Zr metal and Cl₂ gas in a sealed tube and investigated its structure at 100, 150, 200, 250, and 300 K. At 300 K, the SCXRD analysis indicates that ZrCl₄ crystallizes in the orthorhombic space group Pca2₁ [a = 6.262 (9), b = 7.402 (11), c = 12.039 (17) Å, and V = 558.0 (14) ų] and consists of infinite zigzag chains of edge‐sharing ZrCl₆ octahedra. This chain motif is similar to that observed previously in ZrCl₄, but the structural parameters and space group differ. In the temperature range 100–300 K, no phase transformation was identified, while elongation of intra‐chain Zr…Zr [3.950 (1) Å at 100 K and 3.968 (5) Å at 300 K] and inter‐chain Cl…Cl [3.630 (3) Å at 100 K and 3.687 (9) Å at 300 K] distances occurred.     

Interaction of cyclopentadienyl carbonyl phosphine complexes of manganese with Lewis acids. Infrared Spectra*

From IR-spectroscopic studies it is shown that phosphine derivatives of cyclopentadienylmanganese tricarbonyl interact reversibly with SnCl₄ and another Lewis acids in CH₂Cl₂ solution. The structures of the resulting complexes are discussed. Complex formation is favoured as the electron-donor properties of both the π-ring substituents and of the phosphine ligands attached to manganese atom are increased. The ability of Lewis acids to undergo such complex formation follows the series: SnCl₄ > SbCl₃ > HgCl₂ > GeCl₄.     

Thermochemical and structural investigations on alkali metal chlorides-iron(III)-chloride systems

The pseudobinary systems ACl?FeCl₃ (A=Na, K, Rb, Cs) were reinvestigated by means of differential thermal analysis and X-ray powder diffraction. The existence of the compounds AFeCl₄ (A=Na?Cs) and Cs₃Fe₂Cl₉ could be confirmed; Cs₃Fe₂Cl₉ is a stable compound which decomposes to CsCl and CsFeCl₄ above 270°C. Additionally, two Rb-compounds—Rb₃FeCl₆ and Rb₃Fe₂Cl₉—were found, which decompose, when heated, in the solid state. Rb₃Fe₂Cl₉ is isotypic with the analogous Cs-compound; Rb₃FeCl₆ has the Cs₃BiCl₆ structure. Cs₃FeCl₆ is isotypic with Cs₃CrCl₆, a recently found orthorhombic variant of the elpasolite type.     

Reductive coupling of α,β-enones I: Reduction of methyl-vinyl ketone and mesityl oxide.

Reductive coupling of methyl-vinyl ketone with TiCl₄-Mg gives pinacol $\text{1}$ (25%). According to the reducing agents, mesityl oxide yields 2,4,5,7-tetramethyl-octa-2,4,6-triene $\text{3}$ (with 4TiCl₃-LialH₄), triene $\text{3}$ or 2,4,5,7-tetramethyl-octa-2,6-dien-4,5-diol $\text{5}$ (with TiCl₄-Mg), pinacol $\text{5}$ (with VCl₃-Mg), and 2-acetyl-1,3,3,4,4-pentamethyl-cyclopentane $\text{7}$ (with CrCl₃-Mg or FeCl₃-Mg or ZrCl₄ or ZrCl₄-Mg) as major products.     

Zirconium(IV)-porphyrins as novel ionophores for fluoride-selective polymeric membrane electrodes

The feasibility of using Zr(IV)-porphyrins as novel ionophores for preparing anion-selective polymeric membrane electrodes is examined. Electrodes constructed using o-nitrophenyl octyl ether plasticized poly(vinyl chloride) membranes containing Zr(IV)-octaethylporphyrin (OEP) dichloride (Zr(IV)[OEP]Cl₂) or Zr(IV)-tetraphenylporphyrin (TPP) dichloride (Zr(IV)[TPP]Cl₂) were found to exhibit enhanced potentiometric selectivity toward fluoride compared to electrodes based on a typical anion-exchanger (e.g. tridodecylmethylammonium chloride). At pH 5.5, the electrodes displayed the following selectivity sequences: ClO₄⁻ > SCN⁻ > I⁻ > F⁻ > NO₃⁻ > Br⁻ > NO₂⁻ > Cl⁻ and F⁻ > ClO₄⁻ > SCN⁻ > I⁻ > NO₂⁻ > NO₃⁻ > Br⁻ > Cl⁻ for membranes doped with Zr(IV)[OEP]Cl₂) and Zr(IV)[TPP]Cl₂, respectively. Both ionophores are shown to operate via a charged carrier mechanism, with 10 mol% of lipophilic tetraphenylborate derivative in the membrane phase required to achieve optimal selectivity. Electrodes prepared with both metalloporphyrin species display super-Nernstian response toward fluoride with slopes typically greater than −100 mV per decade. It is shown, via UV-VIS spectroscopy of the membrane phase, that this behavior occurs due to spontaneous formation of hydroxide ion bridged porphyrin dimers in the membrane in the presence of the lipophilic anionic additive. The dimers are easily converted to monomeric species upon increasing the concentration of fluoride in the sample solution. Decreasing the pH of sample buffer background solution (from pH 5.5 to pH 3) decreases the lower detection limit (DL) of the electrode response toward fluoride (by two-order of magnitude) and improves the electrodes’ selectivity.     

Massenspektrometrische Untersuchungen der Gasphase über CrCl3 und CrCl3/Cl2

Mass Spectrometric Investigations of the Vapor Phase over CrCl₃ and CrCl₃/Cl₂ The vapor in the system CrCl₃/Cl₂ is investigated by Knudsen-cell mass spectrometry in the temperature range between 770 and 910 K. The gaseous molecules CrCl_{3, g} and CrCl_{4, g} are identified mass spectrometrically; the molar heats of formation are determined by 2nd law calculations. CrCl_{3, g}: Δ_fH(298) = ?79.2 kcal; CrCl_4,g: Δ_fH(298) = ?103.2 kcal; the composition of the vapor in equilibrium with condensed CrCl_3,s, CrCl_2,s is calculated (Temperature 773–1273 K).     

Highly active zirconium(IV) catalyst containing sterically hindered hydridotris(pyrazolyl)borate ligand for the polymerization of ethylene

The synthesis and characterization of the novel zirconium (IV) tris(pyrazolyl)borate compound {Tp^Ms*}ZrCl₃ ( 1 ) (Tp^Ms* = hydridobis(3‐mesitylpyrazol‐1‐yl)(5‐mesitylpyrazol‐1‐yl)), as well as its performance in polymerizing ethylene are described. The reaction of ZrCl₄ with 1 equivalent of TlTp^Ms* in toluene at room temperature affords 1 as a white solid in 62% yield. Compound 1 in the presence of MAO showed remarkable productivity using a low Al : Zr molar ratio (6.79×10⁴ kg of PE/(mol Zr·h·[C₂H₄]); toluene, 60°C, Al/Zr = 100). Under identical polymerization conditions, compound 1 and Cp₂ZrCl₂ showed comparable productivities. Compound 1 displayed similar productivities at temperatures in the range of 0–75°C and noticeable productivity at 105°C. The viscosity‐average molecular weight of the polyethylenes depends on the Al : Zr molar ratio and polymerization temperature and varied between 1.09 and 8.98×10⁵ g·mol^–1.     

Nachweis und Anwendung von Gaskomplexen beim Chemischen Transport

Evidence and Applications of Gaseous Complexes during the Chemical Transport By means of the chemical transport method the formation of gaseous complex compounds has been observed. Using Al₂Cl₆ as a transport agent, the chlorides FeCl₂, CoCl₂, NiCl₂, CuCl₂, PdCl₂, PtCl₂, MoCl₃, YCl₃, LaCl₃, ThCl₄ and UCl₄ are transported within a temperature gradient. Similary are transported by means of Ga₂Cl₆ the chlorides CoCl₂ and NiCl₂, by means of Fe₂Cl₆ the chlorides FeCl₂, CuCl₂ and YCl₃, by means of NbCl₅ the chlorides NaCl and CrCl₃. Examples concerning the practical application of gaseous complexes are refered.     

Caesiumchromhalogenide Cs3CrCl6, Cs3Cr2Cl9 und Cs3CrBr6 – Darstellung,Eigenschaften, Kristallstruktur

Cesium Chromium Halides Cs₃CrCl₆, Cs₃Cr₂Cl₉, and Cs₃CrBr₆ – Preparation, Properties, Crystal Structure The crystal structures of Cs₃CrCl₆ and Cs₃Cr₂Cl₉ were determined and redetermined by X‐ray single‐crystal studies (space group Pnnm, Z = 6, a = 1115.6(2) pm, b = 2291.3(5) pm, c = 743.8(1) pm, R_f = 7.73%, 1025 unique reflections with I > 2σ(I) (Cs₃CrCl₆); P6₃/mmc, Z = 2, a = 721.7(2) pm und c = 1791.0(1) pm; R_f = 2.06%, 395 unique reflections with I > 2.5σ(I) (Cs₃Cr₂Cl₉). The structure of Cs₃CrCl₆ consists of two different isolated CrCl₆ octahedra and five crystallographic different Cs⁺ ions. The CrCl₆ octahedra form ropes in the direction [001]. Because of orientational disordering of the Cr(1)Cl₆ octahedra and the an only half‐occupation of some cesium and chlorine sites Cs₃CrCl₆ is strongly disordered in direction of the (020) plane. The ionic conductivity of Cs₃CrCl₆, which was expected owing to the great disorder, however, is with 7.3 × 10^–5 Ω^–1 cm^–1 at 740 K relatively small. The compound Cs₃CrBr₆, which was firstly prepared by quenching stoichiometric amounts of CsBr and CrBr₃ from 833 K, is metastable at ambient temperature. It is probably isostructural to Cs₃CrCl₆ as shown by X‐ray powder photographs.     

A Tunable Trifluoromethyliodonium Reagent

Four complexes of MCl₄ (M=Ti, Zr, Hf) with the hypervalent trifluoromethyl iodine reagent trifluoromethyl‐1,3‐dihydro‐3,3‐dimethyl‐1,2‐benziodoxole ( 1 ,=L) are described. With TiCl₄, an I?O bond cleavage occurs, leading to the formation of the trifluoromethyliodonium alcoholate complexes [Ti₂Cl₆(L)₄]Cl₂ ( 2 a ) and Ti₂Cl₈(L) ( 2 b ). Reactions with ZrCl₄ and HfCl₄ form the complexes ZrCl₄(L)₂ ( 3 ) and HfCl₄(L)₂ ( 4 ), respectively, wherein the original I?O bond is retained and elongated compared to that in free 1 . Therefore, the reactivity of 1 can be easily and practically fine‐tuned by addition of different metal chlorides, following the order ZrCl₄/HfCl₄<TiCl₄<2 TiCl₄. Complexes 2 a , 3 , and 4 are remarkably bench‐stable forms of activated reagent 1 , while 2 b is readily accessible in situ. 2 a and 2 b represent the first “real” trifluoromethyliodonium reagents derived from iodanes, that is, with the I?O bond being completely cleaved. The new complexes were shown to be useful for the trifluoromethylation of para‐toluenesulfonate under aprotic conditions.     

Über die Isolierung von Lithiumhexamethylozirkonat(IV) Li2[Zr(CH3)6]

ZrCl₄ reacts with LiCH₃ at molar ratios 1 :>6 in diethylether/toluene mixtures at about ?40°C to from Li₂[Zr((CH₃)₆]. After removal of the solvents the complex compound can be separated from the ether-free residue by redissolving it in toluene. Evaporation of the toluene at ?23°C yields yellow, crystalline Li₂[Zr(CH₃)₆].     

Highly efficient and N-bromosuccinimide-mediated conversion of carbohydrates to 5-hydroxymethylfurfural under mild conditions

Highly efficient and selective conversion of different carbohydrates to 5-hydroxymethylfurfural (HMF) has been successfully performed with N-bromosuccinimide (NBS) as a promoter. In the presence of single NBS, a 64.2 % yield of HMF from fructose was obtained in N-methylpyrrolidone for 2 h. The effects of time, temperature and reaction media are discussed. It was concluded that the preliminary bromination of substrate could improve the generation of HMF compared to the direct dehydration process. Moreover, the HMF yield could be elevated to 79.6 and 82.3 % when FeCl₃ and SnCl₄ were used as the additives, respectively. Furthermore, the addition of CrCl₃ facilitated the conversion pathway from glucose, sucrose, inulin, or cellulose to HMF. A 57.3, 68.2, 62.4, or 6.1 % yield of HMF was, respectively, obtained in the presence of CrCl₃ and NBS under mild conditions, which will therefore generate a promising application strategy for biomass transformation.     

Komplexchemie polyfunktioneller Liganden. XXX. Komplexe des Tetrakis(diphenyl-dichlor-phosphoranomethyl)-methan mit FeCl3, SnCl4 und SbCl5

Complex Chemistry of Polyfunctional Ligands. XXX. Complexes of the Tetrakis(diphenyl-dichloro-phosphoranmethyl)methane with FeCl₃, SnCl₄, and SbCl₅ The reaction of C[CH₂P(C₆H₅)₂Cl₂]₄ and FeCl₃ in the 1:4 stoichiometric quantities results in the formation of the tetraphosphonium salt A and the in 1:2 ratio the spirocyclic compound B has been formed. Coincident with the synthesis of B CH₃CN has been chlorinated to some extend. Surprisingly C[CH₂P(C₆H)₂Cl₂]₄ and SnCl₄ yields the much largely non ionic 1:2 adduct C[CH₂P(C₆H₅)₂Cl₂]₄ · 2 SnCL₄, whereas SbCl₅ reacts to the expected salt C[CH₂P(C₆H₅)₂Cl SbCl₆]₄.     

Group 4 metallocene complexes with non-bridged and tetramethyldisiloxane-bridged methyl-phenyl-cyclopentadienyl ligands: synthesis, characterization and olefin polymerization studies

The non-vicinal methyl-phenyl-substituted zirconocene dichlorides meso-and rac-[Zr{η⁵-(1-Ph-3-Me-C₅H₃)}₂Cl₂] and [Zr(η⁵-C₅H₅){η⁵-(1-Ph-3-Me-C₅H₃)}Cl₂] have been isolated by transmetallation of the lithium salt Li(1-Ph-3-Me-C₅H₃) to ZrCl₄(THF)₂ and [Zr(η⁵-C₅H₅)Cl₃ · DME] (DME = dimethoxyethane), respectively. Similar transmetallation of the lithium salt Li₂[(Me-Ph-C₅H₂SiMe₂)₂O] to MCl₄ gave the ansa-metallocenes [M{η⁵-(Me-Ph-C₅H₂SiMe₂)₂O}Cl₂] (M = Zr, Hf) for which the meso- and rac-diastereomers were separated. The dimethyl and dibenzyl derivatives of these metallocenes were also prepared and the structure of all of these compounds determined by NMR spectroscopy. The molecular structure of rac-[Zr{η⁵-(2-Me-4-Ph-C₅H₂SiMe₂)₂O}Cl₂] was determined by single crystal X-ray diffraction methods. The activity of the dichlorometallocenes/MAO catalysts for ethene and propene polymerization was evaluated.     

Zirconium complexes containing a diarylamido diphosphine ligand: Structural preferences controlled by ligand electronics and sterics

This work describes the preparation of [PNP]ZrX₃ ([PNP]⁻ = [N(o-C₆H₄PⁱPr₂)₂]⁻; X = Cl, Me, CH₂SiMe₃) whose structural preference is found to be a function of the electronic and steric nature of the monodentate ligand X⁻. The reaction of ZrCl₄(THF)₂ with [PNP]Li in toluene at room temperature generates [PNP]ZrCl₃ as a red solid in 60% yield. Alkylation of [PNP]ZrCl₃ with three equivalents of Grignard reagents in diethyl ether at −35 °C produces cleanly [PNP]ZrR₃ (R = Me, CH₂SiMe₃) as yellow crystalline materials. An X-ray diffraction study of [PNP]ZrCl₃ showed it to be a chloride-bridged binuclear species {[PNP]ZrCl₂(μ−Cl)}₂ in which both zirconium atoms are 7-coordinate whereas that of [PNP]ZrMe₃ revealed a mononuclear, 6-coordinate core structure. Interestingly, with the incorporation of more sterically demanding alkyls, [PNP]Zr(CH₂SiMe₃)₃ is a 5-coordinate compound wherein the amido phosphine ligand is κ²-N,P bound to zirconium. The solution structures of these molecules were also assessed by variable-temperature NMR spectroscopy.     

Stereospecificity of catalytic systems MCl3AlEt3 in propylene polymerization reactions

Stereoregularity parameters are measured by different i.r. methods for samples of polypropylene, obtained with catalytic systems MCl₃AlEt₃ (M  Ti, V, Cr and Fe). The degree of stereoregularity of the fractions of these polymers insoluble in boiling n-heptane and n-octane decreases in the order α-TiCl₃ ? δ-TiCl₃ > CrCl₃ > VCl₃ > FeCl₃ which is close to the order of the decrease of MCl and MM distances in the MCl₃ lattices.     

Das Solvosystem Benzoylchlorid, 4. Mitt.: Spektrophotometrische Untersuchungen

Zusammenfassung Das Ausmaß des Chloridionenüberganges von Triphenylchlormethan zu Metallchlorid wurde in Benzoylchlorid spektrophotometrisch ermittelt und ergab folgende Reihung der Cl^–-Akzeptorstärken: SbCl₅FeCl₃>GaCl₃>SnCl₄>BCl₃> ZnCl₂>TiCl₄>SbCl₃>AlCl₃>PCl₅. Die Cl^–-Donorstärken wurden spektrophotometrisch gegenüber Eisen (III)-chlorid untersucht: Et₄NCl>AlCl₃>TiCl₄>SnCl₄>PCl₅>ZnCl₂> SbCl₃>BCl₃>GaCl₃>SbCl₅FeCl₃. Die Unterschiede gegenüber dem Verhalten in Phenylphosphoroxychlorid werden auf die relativ schwächeren O-Donoreigenschaften des Benzoylchlorids zurückgeführt.Mit 4 Abbildungen3. Mitt.:V. Gutmann undG. Schöber, Mh. Chem.88, 404 (1957).