41927-88-2Relevant academic research and scientific papers
Static observation of the interphase between NaBH4 and LiI during the conversion reaction
Hihara, Takehiko,Miyagawa, Reina,Miyazaki, Reona,Onishi, Keita
, (2021/08/10)
To determine the synthesis conditions for NaI–NaBH4–LiI solid solutions in a single phase, the conversion reaction of NaBH4 ?+ ?LiI → NaI ?+ ?LiBH4 was investigated by preparing mixed pellets of NaBH4/LiI. The extent of the reaction was investigated under different reaction temperatures and pressures. Although it was not possible to completely suppress the conversion reaction in this study, the low temperature and high-pressure conditions were shown to be favorable to avoid the presence of LiBH4. A significant point is that the conversion reaction was investigated in a static condition in the form of pellets, whereas most of the metal borohydride-halide composites have been fabricated by ball-milling. The microstructure of NaBH4/LiI mixed pellets at different ageing times was observed by scanning electron microscope (SEM), Auger electron spectroscopy (AES), wavelength dispersive X-ray spectroscopy (WDS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The analysis revealed that the reaction interphase between NaBH4 and LiI occurs in the order of LiI/NaI/LiBH4/NaBH4. It was clearly confirmed that the growth of the NaI layer continued with time even at room temperature. In conjunction with the array of the interphase, the diffusion of Na+ in LiBH4 appears to be a necessary condition for the growth of the NaI layer. The present results suggest that a detailed investigation of the conversion reaction between other metal borohydrides and halides (for example, CeCl3/LiBH4, ZrCl4/KBH4, etc.) in the static condition would likely reveal the diffusion of the new ions in the existing compounds.
Crystal and Electronic Structures of A2NaIO6Periodate Double Perovskites (A = Sr, Ca, Ba): Candidate Wasteforms for I-129 Immobilization
Dixon Wilkins, Malin C.,George, Jonathan,Hyatt, Neil C.,Kim, Eunja,Kirk, Cameron,Knight, Kevin S.,Montoya, Eduardo,O'Sullivan, Sarah E.,Sun, Shi-Kuan,Weck, Philippe F.
, p. 18407 - 18419 (2020/12/23)
The synthesis, structure, and thermal stability of the periodate double perovskites A2NaIO6 (A= Ba, Sr, Ca) were investigated in the context of potential application for the immobilization of radioiodine. A combination of X-ray diffraction and neutron diffraction, Raman spectroscopy, and DFT simulations were applied to determine accurate crystal structures of these compounds and understand their relative stability. The compounds were found to exhibit rock-salt ordering of Na and I on the perovskite B-site; Ba2NaIO6 was found to adopt the Fm-3m aristotype structure, whereas Sr2NaIO6 and Ca2NaIO6 adopt the P21/n hettotype structure, characterized by cooperative octahedral tilting. DFT simulations determined the Fm-3m and P21/n structures of Ba2NaIO6 to be energetically degenerate at room temperature, whereas diffraction and spectroscopy data evidence only the presence of the Fm-3m phase at room temperature, which may imply an incipient phase transition for this compound. The periodate double perovskites were found to exhibit remarkable thermal stability, with Ba2NaIO6 only decomposing above 1050 °C in air, which is apparently the highest recorded decomposition temperature so far recorded for any iodine bearing compound. As such, these compounds offer some potential for application in the immobilization of iodine-129, from nuclear fuel reprocessing, with an iodine incorporation rate of 25-40 wt%. The synthesis of these compounds, elaborated here, is also compatible with both current conventional and future advanced processes for iodine recovery from the dissolver off-gas.
Ion Exchange of Layered Alkali Titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with Alkali Halides by the Solid-State Reactions at Room Temperature
Ogawa, Makoto,Saothayanun, Taya Ko,Sirinakorn, Thipwipa Tip
, p. 4024 - 4029 (2020/04/08)
Ion exchange of layered alkali titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with several alkali metal halides surprisingly proceeded in the solid-state at room temperature. The reaction was governed by thermodynamic parameters and was completed within a shorter time when the titanates with a smaller particle size were employed. On the other hand, the required time for the ion exchange was shorter in the cases of Cs2Ti5O11 than those of K2Ti4O9 irrespective of the particle size of the titanates, suggesting faster diffusion of the interlayer cation in the titanate with lower layer charge density.
Multistep soft chemistry method for valence reduction in transition metal oxides with triangular (CdI2-type) layers
Blakely, Colin K.,Bruno, Shaun R.,Poltavets, Viktor V.
supporting information, p. 2797 - 2800 (2014/03/21)
Transition metal (M) oxides with MO2 triangular layers demonstrate a variety of physical properties depending on the metal oxidation states. In the known compounds, metal oxidation states are limited to either 3+ or mixed-valent 3+/4+. A multistep soft chemistry synthetic route for novel phases with M2+/3+O2 triangular layers is reported.
NEW MOLECULE 5-HYDROXY-L-(4-HYDROXY-3-[124I]IODO-5-METHOXYPHENYL)-7- (4-HYDROXY-3-METHOXYPHENYL)-L,4,6-HEPTATRIEN-3-ONE FOR PET INVESTIGATIONS AND RADIOTHERAPY.
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Page/Page column 27, (2009/12/27)
New molecule 5-Hydroxy- 1 -(4-hydroxy-3-[124I]iodo-5-methoxyphenyl)-7-(4- hydroxy-3-methoxyphenyl)-1,4,6-heptatrien-3-one, obtainable through three different processes of chemical synthesis, all of the same importance, and all starting from the
Origin of the thermal desorption peaks of gases in NaI above 180°C
Sofronov,Kudin,Voloshko, A. Yu.,Kudin,Shishkin
, p. 1314 - 1318 (2010/03/25)
We analyze the origin of the water desorption peaks in NaI above the temperature stability range of the crystalline hydrate NaI ? 2H 2O. The two water desorption peaks at t ≥ 180°C are shown to arise from the decomposition of aqua complexes bas
129I moessbauer spectroscopic study of a metallic MMX chain system
Kobayashi, Atsushi,Kitao, Shinji,Seto, Makoto,Ikeda, Ryuichi,Kitagawa, Hiroshi
, p. 8044 - 8049 (2011/04/16)
One-dimensional iodide-bridged mixed-valence binuclear platinum complexes (the so-called "MMX chains") and their Pt(III) dimer precursors were investigated with 129I Moessbauer spectroscopy. Spectra consisting of two sets of octuplets were observed at low temperatures for a neutral MMX chain complex, Pt2(dtp)4l (dtp = C 2H5CS2-), with various charge-ordering states at the Pt dimers, indicating that the charge-ordering state is in an alternate-charge-polarization phase (ACP: · · ·[Pt2+-Pt3+]-l0.4--[Pt 3+-Pt2+]- · · · -10.3-- · · ·), which is consistent with a previous low-temperature X-ray diffraction study. The estimated valence states of the bridging iodines of [(C2H5)2NH2]4[Pt 2(pop)4l] (pop = H2P2O 52-), with a charge-polarization phase (CP: · · · [Pf-Pt3+]-I0-4-· · · [Pt2+-Pt3+]-I0.4--· · ·), and [H3N(CH2)6NH 3]2[Pt2(pop)4l], with a charge-density-wave phase (CDW: · · · [Pt 2+-Pt2+] · · ·I0.3- -[Pt3+-Pt3+]-I30.3- · · ·), suggest that the covalent bond interaction is dominant in the CDW phase, whereas the Coulomb interaction is dominant in the CP phase. The estimated absolute quadrupole coupling constant (QCC) values for negatively charged MMX chain complexes with pop ligands are larger than those for neutral MMX chain complexes with CH3CS2- (dta) ligands, implying that the Madelung potential formed by the more-negative pop ligands and countercations effectively contributes to the physical properties of the pop system. The three Pt(III) dimer complexes Pt2(dta)4l 2, Pt2(dtp)4l2, and K 4[Pt2(pop)4l2] showed almost the same isomer shifts, indicating that the valence state of the iodide ion (1 0.5-) depends negligibly on the terminal ligand. The QCC value observed for K4[Pt2(pop)4l2] was larger than those for Pt2(dta)4l2 and Pt 2(dtp)4l2, originating from the anisotropic arrangement of the iodide anions, which form layers lying on the ab plane in the crystal.
Chemical synthesis of aluminum nitride nanorods in an autoclave at 200 °C
Fu, Li,Xu, Liqiang,Duan, Junling,Li, Ting,Yang, Lishan,Qian, Yitai
, p. 622 - 623 (2011/04/21)
Hexagonal phase aluminum nitride (AlN) nanorods have been prepared via a chemical reaction from Al, I2, and NaN3 in an autoclave at 200°C. Electron microscopy investigations show that the nanorods have diameters ranging from 50 to 100nm and lengths up to several micrometers. Thermal gravimetric analysis reveals that the sample has good thermal stability below 600°C, and room-temperature photoluminescence (PL) of the sample shows a strong emission peak centered at 397 nm. Copyright
METHODS FOR SYNTHESIZING AMMONIA BORANE
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Page/Page column 4; 11; 6, (2008/06/13)
Methods of synthesizing ammonia borane are provided. The methods comprise reacting at least one amine borane with ammonia such that ammonia borane is produced. Ammonia borane has a chemical formula Of NH3-BH3 and provides a good source of storage hydrogen making it useful in a variety of applications including a potential hydrogen source for fuel cells. The methods can further comprise separating the ammonia borane from the other products of the reaction. Exemplary methods can produce ammonia borane having purity greater than about 90 percent. In further examples, the methods can produce ammonia borane having purity greater than about 95 percent or greater than about 99 percent.
Process for the preparation of radioactive labeled estradiol
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Page/Page column 3-4, (2008/06/13)
A method for producing a high yield of an estradiol labeled at the 16-alpha position thereof with a radioactive iodine, especially 123I, for use as an imaging agent. The method includes the step of mixing a source of 123I sodium iodine with 16-beta-bromoestradiol-17-beta and benzo-15-crown-5-ether in a water and organic solvent solution and heating under controlled temperature in the range from 90 to 120° Centigrade for sufficient time to react the iodide with the estradiol. Thereafter, resulting 16-alpha-123I iodoestradiol-17-beta is separated from the resultant mixture using high pressure liquid chromatography and then sterilized.
