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101.
Yoshiaki Hidaka Takuji Nakamura Aya Miyauchi Toshihiko Shiraishi Hiroyuki Kawano 《国际化学动力学杂志》1989,21(8):643-666
Propyne (p-C3H4) or allene (a-C3H4) mixtures, highly diluted with Ar, were heated to the temperature range 1200–1570 K at pressures of 1.7–2.6 atm behind reflected shock waves. The thermal decompositions of propyne and allene were studied by both measuring the profiles of the IR emission at 3.48 μm or 5.18 μm and analyzing the concentrations of reacted gas mixtures. The mechanism and the rate constant expressions were discussed from both the profiles and the concentrations of reactant and products obtained. The rate constant expressions for reactions, (1) p-C3H4 → a-C3H4, (?1) a-C3H4 → p-C3H4, and (5) p-C3H4 + H → CH3 + C2H2 were evaluated. 相似文献
102.
Yutaka Nagai Nakahara Kouji Yoneyama Yoshifumi Kawano Katsuyasu Tanaka Katsumi Nakata Ryouhei 《Journal of Physics and Chemistry of Solids》2004,65(11):1861-1870
The characteristics of high-temperature ionic thermocurrent (HT ITC) in CaF2 doped with different sodium concentrations were studied by the Teflon-insulated electrode ITC method. It was shown that, with increasing sodium concentration, the HT ITC band moved toward a Na+-FV dipole band with a peak at 162 K. The results of analyses of the HT ITC spectra using an equivalent electric circuit proved that the activation energy of space charge migration related to HT ITC was also strongly dependent on the doped sodium concentrations if varied from 0.94 to 0.46 eV with increasing sodium concentration in our ITC study. In addition, the broadening of the Na+-FV dipole band was observed in 3 nominal mole% NaF-doped CaF2, which was accompanied by a considerable decrease of the activation energy from 0.46 to 0.29 eV without showing marked temperature shifts of the peak ITC bands. 相似文献
103.
Tetsuya Tsujihara Sayaka Endo Tsunayoshi Takehara Takeyuki Suzuki Satoru Tamura Tomikazu Kawano 《Tetrahedron letters》2018,59(25):2450-2453
The synthesis of helically chiral [6]helicene-based sulfonic acid and sulfonamide from enantiomerically pure 1-acetylthio-5,6,9,10-tetrahydro[6]helicene is reported. The first helically chiral disulfonimides were developed as a synthetic application of [6]helicene-based sulfonamide. This new class of organocatalysts was tested in an asymmetric Mukaiyama aldol reaction to obtain up to quantitative yields and enantioselectivities up to 24%. 相似文献
104.
Shimada Y Akane H Taniguchi N Matsuhisa A Kawano N Tanaka A 《Chemical & pharmaceutical bulletin》2005,53(5):589-590
Stereoselective synthesis of methyl (Z)-(4,4-difluoro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-ylidene)acetate (1a) is described. Z-selectivity of the Horner-Wadsworth-Emmons (HWE) reaction was obtained based on an investigation of the reaction conditions for introduction of a methylidene group onto the 5-position of benzazepine. 相似文献
105.
Masakazu Iwamoto Shin-Ichiro Nakamura Hideto Kusano Shuichi Kagawa 《Journal of inclusion phenomena and macrocyclic chemistry》1986,4(1):99-103
The adsorption and/or decomposition pathway of Fe2(CO)9 or Fe3(CO)12 on hydrated or dehydrated NaY zeolites has been studied by an ESR technique. The adsorption resulted in the formation of three paramagnetic species withg
iso=2.0450, 2.0378, and 2.0016, which were attributable to Fe3(CO)11
–, Fe2(CO)8
–, and Fe(CO)4
– anion radicals, respectively. These radicals have been suggested as intermediates in the formation of HFe3(CO)11
– on the hydrated NaY zeolite and Fe3(CO)12 on the dehydrated NaY zeolite. 相似文献
106.
M. Kawano J. Falandysz T. Wakimoto 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(3):501-504
Instrumental neutron activation analysis (INAA) was performed for measurement of extractable organohalogens (EOX) in blubber
samples of Weddell seals (Leptonychotes weddelli) from Antarctica. EOX were detected in all the analyzed samples. The concentration order of EOX was: extractable organochlorine
(EOCl)>extractable organobromine (EOBr)>extractable organoiodine (EOI). Their levels increased gradually with aging as with
other man-made persistent organic pollutants (POPs) such as PCBs and DDTs. 相似文献
107.
Daniel F. Kawano Bruna Z. Costa Katherine L. Romero-Orejn Hugo C. Loureiro Dosil P. de Jesus Anita J. Marsaioli 《Molecules (Basel, Switzerland)》2021,26(9)
1-Pyrrolines are important intermediates of active natural products, such as the 2,5-dialkyl-1-pyrroline derivatives found in fire ant venoms. Here, 5-hexyl-2-methyl-3,4-dihydro-2H-pyrrole was synthesized by the enzymatic transamination/cyclization of 2,5-undecadione, and enantiodifferenciation was successfully achieved by capillary electrophoresis with sulfobutyl ether--cyclodextrin as the chiral selector. The rationale of the enantiomeric discrimination was based on the results of a docking simulation that revealed the higher affinity of (S)-5-hexyl-2-methyl-3,4-dihydro-2H-pyrrole for the sulfobutyl ether--cyclodextrin. 相似文献
108.
Okamoto Y Kawano M Kawabata T Kubota T Hiromitsu I 《The journal of physical chemistry. B》2005,109(1):288-296
The elucidation of a molecular structure of the active sites (i.e., the Co-Mo-S phase) of Co-Mo hydrodesulfurization catalysts has received extensive attention. In the present study, we unambiguously determined, for the first time, the NO adsorption behavior and magnetic property of the Co-Mo-S phase by preparing unique Co-Mo/Al(2)O(3) catalysts (CVD-Co/MoS(2)/Al(2)O(3)), in which all the Co atoms are present as the Co-Mo-S phase. The catalysts were characterized by NO adsorption (pulse technique and FTIR), Co K-edge XANES, and the magnetic susceptibility and effective magnetic moment of Co. Nitric oxide molecules were adsorbed on 33% of the Co atoms in CVD-Co/MoS(2)/Al(2)O(3) after sulfidation and on only half of the Co atoms even after an H(2)-treatment of the sulfided catalyst at 573-673 K. The Co atoms in CVD-Co/MoS(2)/Al(2)O(3) exclusively exhibited an antiferromagnetic property, indicating that even-numbered Co atoms are interacting with each other in the Co-Mo-S phase. A Co-Mo/Al(2)O(3) catalyst, prepared by a conventional impregnation technique, was composed of the antiferromagnetic Co sulfide species as observed in CVD-Co/MoS(2)/Al(2)O(3) in addition to Co(9)S(8). On the basis of the NO adsorption behavior and magnetic property, it is empirically proposed that the structure of the Co-Mo-S phase is represented as a Co sulfide dinuclear cluster located on the edge of MoS(2) particles. The magnetic property of Co/Al(2)O(3) sulfide catalysts depended on the preparation method. 相似文献
109.
Kazuhiko Hashimoto Shin-Ichiro Imanishi Masahiko Okada Hiroshi Sumitomo 《Journal of polymer science. Part A, Polymer chemistry》1992,30(2):211-220
A novel AB-type block copolymer composed of dextran and polyamide sequences was prepared through the following two approaches. One is a coupling reaction of a terminal functional group introduced in the dextran chain with that in the polyamide chain, such as the reaction of an amine group with an acyllactam group or that of a lactone group with an amine group at the corresponding chain ends. The other is an anionic polymerization of a bicyclic lactam activated with a trimethylsilylated dextran derivative having an acyllactam end group. The latter procedure was found to be more effective for the preparation of the block copolymer having a high molecular weight polyamide sequence. 相似文献
110.
The individual adsorption behaviour of potassium, cupric, zinc, cadmium and nitrate ions on hydrous lead dioxide (HLD) was investigated. HLD was found to be an amphoteric ion-exchanger with an equi-adsorption point in the vicinity of pH 4.6. For bivalent metal ions, the amount of adsorption increased with pH (at pH > 3) and there was almost 100% adsorption at pH > 6. Both the adsorption capacity and the adsorption affinity on HLD were in the order copper(II) > zinc(II) > cadmium(II). 相似文献