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M. Takeuchi S. Tanaka M. Yamawaki S. Tachimori 《Journal of Radioanalytical and Nuclear Chemistry》1995,191(1):189-199
The coextraction equilibrium of technetium(VII) and uranium(VI) from nictric acid solution was studied in a system involvingn-octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) in decalin. Stoichiometry of technetium, uranium and CMPO in the Tc-U-CMPO complex was obtained from the distribution data by slope analysis. The results indicated that the enhanced extraction of technetium was caused by the formation of UO2NO3TcO4·nCMPO (wheren=2 and/or 3). It was found that this coextraction of technetium with uranium was well explained by using ion exchange reaction between UO2(NO3)2·2CMPO complex and TcO
4
–
. 相似文献
25.
Chiral β-dimethylaminoalkylphosphines were prepared starting with amino acids, (S)-alanine, (S)-phenylalanine, (R)-phenylglycine, (S)-valine, and (R)-tert-leucine. The chiral phosphines were found to be highly efficient ligands for a nickel catalyzed asymmetric Grignard cross-coupling reaction (38~94% optical yield). 相似文献
26.
Toyohide Takeuchi Mototada Watanabe Tadashi Hamanaka Hiroki Haraguchi Daido Ishii 《Journal of separation science》1990,13(9):606-609
Capillary columns of 0.3-0.5 mm i.d. packed with 3- to 30-μm silica-based stationary phases for liquid chromatography were used for gas chromatographic separation of hydrocarbons. Column efficiencies were evaluated for various commercially available packing material. The best column efficiency was achieved with 5-μm octadecyl group bonded silica gel, the surface of which was coated with a poly (dimethylsiloxane) film. The 30-cm column produced 11,000 theoretical plates. 相似文献
27.
Tatsuro Ouchi Tamio Nishimura Minoru Imoto 《Journal of polymer science. Part A, Polymer chemistry》1976,14(11):2695-2702
It was found recently that the system of nylon 3, copper(II) ion, and water could initiate a radical polymerization of methyl methacrylate(MMA). In the present paper, the effect of average chain length of the molecules of nylon 3 on the rate of polymerization of MMA was studied. The rate increased with the chain length of nylon 3. This result was explained well by the fact that the shorter nylon 3 forms a complex with copper (II) ion more easily than longer nylon 3. It was assumed that the shorter nylon 3 fills three or four coordination sites of copper(II) ion and loses the ability to initiate the polymerization. The efficiency of grafting of MMA and the degree of polymerization of MMA homopolymer were independent of the chain length of nylon 3. 相似文献
28.
Kei Matsuzaki Tamio Yasukawa 《Journal of polymer science. Part A, Polymer chemistry》1967,5(3):511-520
Butadiene was polymerized by catalysts of the type: metal acetylacetonate (metal: Ti to Ni in the periodic table)–triethylaluminum–aluminum halide, with various ratios of triethylaluminum to aluminum halide. The minimum cis content was observed with vanadium catalyst in all cases, while the minimum polymer yields were observed with the iron and the manganese catalysts. These transition metal effects are discussed in terms of the crystal field theory, and it is suggested that the electrostatic interaction between the nearly nonbonding electrons of transition metal atom and a butadiene molecule or a growing end of the polymeric chain plays an important role in the stereoregular polymerization of butadiene by homogeneous Ziegler-Natta catalysts. 相似文献
29.
Huynh MH Witham LM Lasker JM Wetzler M Mort B Jameson DL White PS Takeuchi KJ 《Journal of the American Chemical Society》2003,125(2):308-309
fac-[RuII(Cl)(dpp)(L3)]+ (L3 = tris(pyrid-2-yl)methoxymethane (tpmm) = [1A]+ and tris(pyrid-2-yl)pentoxymethane (tppm) = [1B]+ and dpp = di(pyrazol-1-yl)propane) rapidly undergo ligand substitution with water to form fac-[RuII(H2O)(dpp)(L3)]2+ (L3 = tpmm = [2A]2+ and tppm = [2B]2+). In the structure of [2A]2+, the distorted octahedral arrangement of ligands around Ru is evident by a long Ru(1)-O(40) of 2.172(3) A and a large angle O(40)-Ru(1)-N(51) of 96.95(14) degrees . The remarkably short distance between O(40) of H2O and H(45a) of dpp confirms the heteroscorpionate ligand effect of dpp on H2O. [2B]2+ aerobically catalyzes methyl p-tolyl sulfide to methyl p-tolyl sulfoxide in 1,2-dichlorobenzene at 25.0 +/- 0.1 degrees C under 11.4 psi of O2. Experimental facts in support of this aerobic sulfide oxidation are the absence of H2O2 and the oxidative reactivity of the putative Ru(IV)-oxo intermediate toward methyl p-tolyl sulfide, 2-propanol, and allyl alcohol. This study provides the first documented example of aerobic-sulfide oxidation catalyzed by the remarkably labile heteroscorpionate Ru(II)-aqua complex without the formation of a highly reactive peroxide as an intermediate. 相似文献
30.
[reaction: see text] A formal total synthesis of the sex attractant of male dried bean beetle, methyl (R,E)-(-)-tetradeca-2,4,5-trienoate, was achieved by a new efficient route utilizing the Pd-catalyzed asymmetric allene synthesis reaction. It was found that the atropisomeric biaryl bisphosphine (R)-segphos showed better enantioselectivity than (R)-binap in the Pd-catalyzed reaction for preparing alkyl-substituted axially chiral allenes. 相似文献