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81.
Tetsuya Shishido Hideto Tsuji Yunzhi Gao Hideshi Hattori Hideaki Kita 《Reaction Kinetics and Catalysis Letters》1993,51(1):75-79
Temperature-programmed desorption study of C18O2 adsorbed on MgO has revealed that the desorbed carbon dioxide is composed exclusively of C16O2, indicating that the adsorbed CO2 species roll over the MgO surface. 相似文献
82.
Hideto Akiba Hiroyuki Nishide Eishun Tsuchida Hideki Omichi Jiro Okamoto 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):1125-1135
Acrylic acid (AA) and acrylamide (AAm) were graft copolymerized onto polyethylene powder by the preirradiation method. The PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) rapidly adsorbed Tb ion with an efficiency higher than did PE powder grafted with AA (PE-g-AA). The complex formation constant of Tb ion with PE-g-(AA-co-AAm) was larger than that with PE-g-AA because the introduction of the acrylamide part decreased the steric hindrance for complexation between Tb and the carboxyl group of the graft chains. Tb ion was efficiently separated from transition metal ions, such as Co, upon passage of a solution through a column packed with PE-g-(AA-co-AAm). 相似文献
83.
Akimitsu Ishihara Satoshi Tominaka Shigenori Mitsushima Hideto Imai Osamu Sugino Ken-ichiro Ota 《Current Opinion in Electrochemistry》2020
To obtain an ideal electrocatalysts for hydrogen fuel cells, we investigated group 4 and 5 oxide-based compounds because of their high degree of freedom. First-principles calculations revealed that oxide surfaces such as those of titanium oxide could break down the universal scaling to achieve the ideal state of the oxygen reduction reaction. We experimentally clarified that the active sites were oxygen vacancies for tantalum and zirconium oxides, in addition to doped foreign elements and crystalline structures for titanium oxide. We successfully demonstrated that precious metal-free and carbon-free oxide-based cathodes have high quality active sites and superior durability in 0.1 M sulfuric acid at 80°C. Our strategy was developed as follows: (1) Active sites are created on the oxide surface by modifying the crystalline structure and electronic states and (2) electrons participating in the oxygen reduction reaction are supplied by nanosized oxide particles and oxide films through the tunneling effect of electrons. 相似文献
84.
Prof. Yuki Arakawa Yuko Ishida Prof. Hideto Tsuji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(17):3767-3775
The twist–bend nematic (NTB) phase with a heliconical nanostructure of the local director generating symmetry breaking by achiral bent-shaped molecules is a hot topic of current liquid-crystal science. As opposed to the most common methylene-linked dimers, this study demonstrates chalcogen ether- and/or thioether-linked 6-(4-cyanophenyl)-2-naphthyl-based liquid-crystal dimers with symmetric and asymmetric π-conjugated mesogenic-arm structures that exhibit the NTB phase. Although the symmetric bis(ether)-linked dimer exhibits only the conventional nematic (N) phase, the asymmetric bis(ether)-linked dimer can form the NTB phase. All thioether-linked dimers form the NTB phase, wherein the dimers with asymmetric arms vitrify in the NTB phase on cooling to room temperature. The phase transitions are discussed in terms of the chalcogen linkage combination, mesogenic-arm symmetry, and spacer length. It is revealed that thioether-linked dimers based on asymmetric π-conjugated mesogenic arms with terminal cyano groups are highly beneficial for the realization of materials that form a wide range of NTB phases and glassy NTB states at room temperature. 相似文献
85.
Isotactic and optically active poly(D ‐lactic acid) (PDLA) and phenyl‐substituted poly(lactic acid)s (Ph‐PLAs), i.e., poly(D ‐phenyllactic acid) (Ph‐PDLA) and poly(L ‐phenyllactic acid) (Ph‐PLLA), were synthesized and stereospecific interactions between the synthesized polymers were investigated by their thermal properties and crystallization behavior using differential scanning calorimetry (DSC). The DSC measurements indicated that PDLA is miscible with Ph‐PLAs and that the attractive interaction between PDLA and L ‐configured Ph‐PLA is higher than that between PDLA and D ‐configured Ph‐PDLA. In other words, the latter result means that poly(lactic acid) (PLA) has a higher stereoselective attractive interaction with Ph‐PLA with the reverse configuration than with Ph‐PLA of the same configuration. These results strongly suggest that PLA‐based materials with a wide variety of physical properties and biodegradability can be fabricated by blending them with substituted PLAs with the reverse and same configurations.
86.
87.
Sawada T Nishiyama Y Tabuchi W Ishikawa M Tsutsumi E Kuwahara Y Shosenji H 《Organic letters》2006,8(10):1995-1997
[reaction: see text] Tetramethoxy[2.1.2.1]metacyclophane ([2.1.2.1]MCP) was prepared by the pinacol coupling reaction of diphenylmethane dialdehyde. The treatment of [2.1.2.1]MCP with trimethylsilyl chloride and sodium iodide yielded two unexpected calixarene derivatives, cone (hemisphere) and 1,2-alternate types, instead of octahydroxy[2.1.2.1]MCP. The X-ray structure of the cone-type derivative and its inclusion property with acetonitrile were also discussed. 相似文献
88.
The addition of carbon radicals to glyoxylic imines was studied using zinc dust as a radical initiator. The zinc-mediated radical reaction of glyoxylic oxime ethers and hydrazones proceeded smoothly to give the alkylated products via a carbon-carbon bond-forming process in aqueous media. The reaction of the oxime ethers and hydrazones having an Oppolzer's camphorsultam group provided the corresponding alkylated products, which could be converted into enantiomerically pure alpha-amino acids. The diastereoselectivities observed in the reaction of hydrazones were better than those obtained in the reaction of oxime ethers. 相似文献
89.
Ueda M Miyabe H Teramachi M Miyata O Naito T 《The Journal of organic chemistry》2005,70(17):6653-6660
The intermolecular radical addition to chiral nitrones 2, 4, 5, and 16 was studied. The isopropyl radical addition to Oppolzer's camphorsultam derivative 2 of glyoxylic nitrone proceeded with excellent diastereoselectivity to give the desired isopropylated product 3a accompanied by the diisopropylated product 3b. A high degree of stereocontrol in the reaction of cyclic nitrone 4 was achieved. The ethyl radical addition to nitrone 4 with triethylborane afforded the desired ethylated product 9a accompanied by the diethylated product 10a and the ethylated nitrone 11a. To evaluate the utility of cyclic nitrone 4, several alkyl radicals were employed in the addition reaction, which afforded the alkylated products 9b-d with excellent diastereoselectivities. In the presence of Mg(ClO(4))(2), the ethyl radical addition to BIGN 16 afforded selectively syn isomers. In contrast, the alkyl radical addition to 16 took place even in the absence of Lewis acid to give anti isomers. 相似文献
90.