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Ethyl pentafluoropropanethioate, prepared by treating ethanethiol with hexafluoro-1, 2-epoxypropane in the presence of triethylamine, was found to be a convenient pentafluoropropionylating agent for amines and alcohols. 相似文献
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Toshiyuki Fujii Frédéric Moynier Arnaud Agranier Emmanuel Ponzevera Minori Abe Akihiro Uehara Hajimu Yamana 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):261-265
Environmental transport of Tl is affected by redox reaction between Tl(I) and Tl(III) and ligand exchange reactions of them. In order to deepen the knowledge of Tl chemistry, we investigated fractionation of Tl stable isotopes (203Tl and 205Tl) in a chemical exchange system. Tl isotopes were fractionated in a liquid–liquid extraction system, in which aqueous and organic phases are hydrochloric acid solution and dichloroethane including a crown ether, respectively. After purification by ion-exchange chemistry, the isotope ratio of 205Tl/203Tl in equilibrated aqueous phase was measured precisely by multiple-collector–inductively-coupled-plasma–mass-spectrometry. A large isotope fractionation >1 ‰ was found. Electronic structures of possible Tl species (hydrated Tl+, Tl3+, and Tl chlorides) were calculated by ab initio methods, and the isotope fractionation factor was theoretically obtained. The isotope fractionation via intramolecular vibrations was calculated to be much smaller than the experimental result. The isotope fractionation via isotopic change in nuclear volume, named the nuclear field shift effect, was calculated to be >1 ‰ in Tl(I)–Tl(III) redox systems and/or ligand exchange systems of Tl(III). The nuclear field shift effect was found to be the major origin of Tl isotope fractionation. 相似文献
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Toshiyuki Fujii Genki Okude Akihiro Uehara Shun Sekimoto Hirokazu Hayashi Mitsuo Akabori Kazuo Minato Hajimu Yamana 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):181-187
Distribution behavior of Ce(III), Am(III), and Cm(III) between tri-n-butyl phosphate solution and molten calcium nitrate hydrate Ca(NO3)2·RH2O or molten calcium chloride hydrate CaCl2·RH2O was studied radiochemically. In Ca(NO3)2·RH2O systems, maximum separation factors of Ce and Cm to Am were observed to be 12 (Ce/Am) and 1.7 (Cm/Am). The distribution
ratios of these elements increased with the decrease of water activity in the hydrates, and the extractabilities at the water
deficient region was less sensitive compared to those at the water abundant region. This trend was similar to the coordination
circumstance change observed in electronic absorption spectra of Nd(III) in the hydrates. 相似文献
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Young's modulus and stress-optical coefficient of self-sustained gel film of CH3SiO3/2 were measured. Young's modulus varied from 1.1 to 1.5 GPa, depending on the structural state of the film. It increased with an increase in the degree of polymerization that was induced by heat treatments, and also increased with subsequent exposure to the ambient condition. The stress-optical coefficient was 6.3 × 10–12 Pa–1 for a sample treated at 120°C. The compliance of the film seems to depend mainly on the intermolecular structure of Si–CH3...CH3–Si as well as hydrogen bonding due to silanols and adsorbed water. 相似文献
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Perfluoro-2-propoxypropionic acid, which was prepared by the anionic dimerization of hexafluoro-1,2-epoxypropane, was optically resolved via diastereomeric salt formation with chiral amines. The optically pure (+) and (?) perfluoro-2-propoxypropionic acids thus obtained were found to be a convenient chiral reagent for determining enantiomeric compositions of α-amino acids by means of 19F nmr analysis. 相似文献
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The total evaporation technique of thermal ionization mass spectrometry was applied to the isotopic analysis of chromium. High measurement reproducibility of the chromium isotope ratios was verified (2 S.E. < 0.05% (53Cr/52Cr)), while a clear mass fractionation effect was observed by using conventional measurement technique. The chromium isotope ratios analyzed by the total evaporation method were not affected by the sample amount on the rhenium filament (50-500 ng Cr). The isotopic analysis under the coexistence of zinc was also performed, and its effect to the chromium isotope ratios was confirmed. 相似文献
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