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121.
The nature of active titanium species for epoxidation of olefins with H2O2 and t-butyl hydroperoxide has been investigated for titanium silicalite (TS-1), titania silica (TiO2/SiO2) prepared by a sol-gel method, and titanium oxide supported on silica by a CVD method (TiO2/SiO2-CVD). IR and XANES analyses suggested that Ti in TiO2/SiO2 and TiO2/SiO2-CVD has a tetrahedral configuration bonded to SiO2 and that in TS-1 has a configuration composed of >Ti=O or related to it. Their configurations are closely related to their reactivities for epoxidation of olefins in which the former works with t-butyl hydroperoxide and the latter with H2O2. 相似文献
122.
123.
We have measured the two-color double resonance enhanced four-photon ionization and the fluorescence de-enhanced spectra of nitric oxide by using two tunable pulsed dye lasers. The spectra show clear structure in the third-photon (8.2 eV) region. Also discussed is the multiphoton ionization mechanism in the resonance state. 相似文献
124.
Gallic acid was separated from a n-butanol extract of the fruit of Cornus officinalis Sieb. et Zucc by high-speed countercurrent chromatography in two steps using two solvent systems composed of ethyl-acetate-ethanol n-butanol-water (5:1.8:6, v/v/v) and ethyl acetate-ethanol-water (5:0.5:6, v/v/v) successively. From 1 g of n-butanol extract the method produced 60 mg of gallic acid at a purity of 97%. 相似文献
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126.
Toru Tachihara Susumu Ishizaki Yoshiko Kurobayashi Hiroshi Tamura Youichi Ikemoto Atsushi Onuma Keisuke Yoshikawa Tetsuya Yanai Takeshi Kitahara 《Helvetica chimica acta》2003,86(2):274-279
All possible stereoisomers of imine derivatives 1 – 4 , which have the characteristic roast odor of seafood, were synthesized. As a result of odor evaluation of all isomers, we found that each isomer has a different and characteristic odor of roasted seafood. 相似文献
127.
128.
H Miyazaki N Ohkawa N Nakamura T Ito T Sada T Oshima H Koike 《Chemical & pharmaceutical bulletin》1989,37(9):2379-2390
Six-membered lactone and tetrahydropyran analogues of platelet-activating factor (PAF), 4-11, and related antagonistic derivatives 41-46 were synthesized. None of the delta-lactones 4-7 showed PAF-like activities, while the corresponding cyclic ethers 8, 9 and 11 were slightly active. Some of the cyclic antagonists showed more potent inhibitory activities than the open chain antagonist CV-3988 against platelet aggregation (rabbit platelet-rich plasma, IC50) and hypotension (rat, ID50) induced by C16-PAF: e.g. dl-3-[6-[O-(trans-3-heptadecylcarbamoyloxytetrahydropyran-2- yl)methyl]phosphonoxy]hexylthiazolium (inner salt) (41d) (IC50 5.5 x 10(-7) M, ID50 0.046 mg/kg, i.v.); dl-3-[5-[O-(cis-3-heptadecylcarbamoylthiotetrahydropyran-2- yl)methyl]phosphonoxy]pentylthiazolium (inner salt) (43c) (IC50 5.7 x 10(-7) M, ID50 0.076 mg/kg, i.v.). 相似文献
129.
130.
D'Souza F Chitta R Gadde S Zandler ME Sandanayaka AS Araki Y Ito O 《Chemical communications (Cambridge, England)》2005,(10):1279-1281
A highly stable porphyrin-fullerene conjugate with defined distance and orientation, was formed using a newly developed 'two-point' binding strategy involving axial-coordination and cation-crown ether complexation; photochemical studies performed in benzonitrile revealed efficient charge separation and slow charge-recombination in the supramolecular complex. 相似文献