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991.
Liquid—liquid equilibrium data were obtained for two ternary systems: acetonitrile— ethanol—cyclohexane at 40°C, and acetonitrile—2-propanol—cyclohexane at 50°C. Binary vapor—Liquid equilibrium data were measured for acetonitrile—2-propanol at 50°C. The binary parameters of the Zeta and effective Zeta equations were evaluated from equilibrium data for binary pairs. The parameters obtained were used to predict the ternary liquid—liquid equilibrium data for six systems involving the present systems and the ternary vapor—liquid equilibrium data for one completely miscible system and two partially miscible systems without adding any ternary parameter. A heterogeneous area calculated by the Zeta equation is in general too large and does not decrease appreciably with increasing values of the third parameter ζ of the Zeta equation. However, the effective Zeta equation works much better than the original Zeta equation in data reduction. 相似文献
992.
Okumura K Yoshimoto R Uruga T Tanida H Kato K Yokota S Niwa M 《The journal of physical chemistry. B》2004,108(20):6250-6255
Spontaneous dispersion and clustering processes of Pd were measured by means of the energy-dispersive EXAFS method. The spontaneous dispersion of bulky metal Pd into highly dispersed PdO was directly observed on the H-type zeolite in the atmosphere of O2. In contrast to H-type zeolites, simple oxidation of the agglomerated Pd was observed on Na-ZSM-5. The structural change of Pd was followed in the atmosphere of hydrogen. The clustering processes of metal Pd depended on the kind of zeolite, and these were categorized into three groups. The first group, i.e., Na-ZSM-5 and H-beta, showed monotonic agglomeration of metal Pd by increasing the reduction temperature. The second group consisted of H-ZSM-5 and H-mordenite where the formation of Pd6 clusters was found. On these zeolites, the generation of Pd6 clusters was reversibly observed upon the repetition of reduction and oxidation treatments. The third group consisted of H-Y and USY zeolites where the formation of Pd13 clusters was observed. From these findings, it was concluded that the crystal structure and acid sites of zeolites had profound influences on the dynamic behavior and the genesis of Pd clusters with various structures. 相似文献
993.
Hiroyuki Kikuchi Yasumasa Tsukitani Kazuo Iguchi Yasuji Yamada 《Tetrahedron letters》1982,23(49):5171-5174
Three new prostanoids, clavulone I(), II() and III(), were isolated from the Japanese Stolonifer Quoy and Gaimard. The structures of these prostanoids were determined on the basis of spectral data and chemical reactions. 相似文献
994.
Studies on the biological activity of tocotrienols 总被引:5,自引:0,他引:5
K Komiyama K Iizuka M Yamaoka H Watanabe N Tsuchiya I Umezawa 《Chemical & pharmaceutical bulletin》1989,37(5):1369-1371
Tocotrienols were evaluated for activity against transplantable murine tumors inoculated i.p. into mouse, and the activities of two tocotrienols and alpha-tocopherols were compared. When the compounds were injected i.p., alpha- and gamma-tocotrienols were effective against sarcoma 180, Ehrlich carcinoma, and IMC carcinoma, and gamma-tocotrienol showed a slight life-prolonging effect in mice with Meth A fibrosarcoma, but the tocotrienols had no antitumor activity against P388 leukemia at doses of 5-40 mg/kg/d. On the other hand alpha-tocopherol had only a slight effect against sarcoma 180 and IMC carcinoma. The antitumor activity of gamma-tocotrienol was higher than that of alpha-tocotrienol. Tocotrienols showed growth inhibition of human and mouse tumor cells when the cells were exposed to these agents for 72 h in vitro, whereas tocopherol did not show any marked cytotoxic activity. Alpha- and gamma-tocotrienols had inhibitory effects on lipid peroxidation of murine microsomes by adriamycin. 相似文献
995.
Hanmura T Ichihashi M Monoi T Matsuura K Kondow T 《The journal of physical chemistry. A》2005,109(29):6465-6470
The reaction process of the production of CrOH(C2H4)2(+) was studied in connection with the ethylene polymerization on a silica-supported chromium oxide catalyst (the Phillips catalyst). Cluster ions CrOH(C2H4)2(+) and CrOH(C4H8)+ were produced by the reactions of CrOH+ with C2H4 (ethylene) and C4H8 (1-butene), respectively, and were allowed to collide with a Xe atom under single collision conditions. The cross section for dissociation of each parent cluster ion was measured as a function of the collision energy (collision-induced dissociation, or CID). It was found that (i) the CID cross section for the production of CrOH+ from CrOH(C2H4)2(+) increases sharply at the threshold energy of 3.16 +/- 0.22 eV and (ii) the CID cross section for the production of CrOH+ and C4H8 from CrOH(C4H8)+ also increases sharply at the threshold energy of 3.26 +/- 0.21 eV. In comparison with the calculations based on a B3LYP hybrid density functional method, it is concluded that two ethylene molecules in CrOH(C2H4)2(+) are polymerized to become 1-butene. The calculation also shows that the dimerization proceeds via CrOH(C2H4)+ (ethylene complex) and CrOH(C2H4)2(+) (ethylene complex), in which the ethylene molecules bind with CrOH+ through a pi-bonding. 相似文献
996.
Takehiko Terao Shiro Maeda Tokio Yamabe Kazuo Akagi Hideki Shirakawa 《Chemical physics letters》1984,103(5):347-351
13C NMR spectra of undoped polyacetylene,(CH)x, have been measured. The existence of 3.4 mol% methylene moieties as defects in the (CH)x chains has been observed in trans-(CH)x. Measurements of partially cis-to-trans isomerized (CH)x suggest the existence of isolated cis regions. 相似文献
997.
Fukuji Higashi Akira Tai Kazuo Adachi 《Journal of polymer science. Part A, Polymer chemistry》1970,8(9):2563-2577
Polymers having polyamine structures were obtained by the condensation reaction between diethyl succinylsuccinate (1,4-diethoxycarbonyl-2,5-dihydroxy-1,4-cyclohexadiene) and aliphatic diamines. The reactions were carried out in high polar solvents such as N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF). The mode of the polymerization reaction and the structure of the polymers were verified by studies of model compounds. The polymers thus obtained were conveniently utilized as coating and adhesive materials and were able to be cast into films. 相似文献
998.
Nakane T Maeda Y Ebihara H Arai Y Masuda K Takano A Ageta H Shiojima K Cai SQ Abdel-Halim OB 《Chemical & pharmaceutical bulletin》2002,50(9):1273-1275
Two new migrated hopane triterpenoids, viz. 4alpha-hydroxyfilican-3-one and fern-9(11)-en-12beta-ol, and olean-18-en-3-one and olean-12-en-3-one as the first example of oleanane compounds from Adiantum ferns were isolated along with many other known triterpenoids from Adiantum capillus-veneris of China and Egypt. Their structures were elucidated by spectroscopic analyses. 相似文献
999.
Shozo Shibata Masamichi Furukawa Eijiro Kamata Kazuo Goto 《Analytica chimica acta》1970,50(3):439-446
The heterocyclic azo compound, 1-[(5-chloro-2-pyridyl)azo]-2-naphthol (5-Cl-β-PAN), forms various coloured metal chelates, which can be extracted with different organic solvents. Chelate stability is greatly affected by pH. The molar absorptivities are usually considerably greater than those of the β-PAN chelate. Although the bathochromic shifts produced on chelation are no greater than those with 5-Br-β-PAN, the selectivity is increased. The reactivity of tri- and tetravalent metal ions is decreased appreciably by introduction of the chlorine. A correct choice of pH, solvent and masking reagent allows 5-C1-β-PAN to be made reasonably selective. 相似文献
1000.
The C-unsubstituted 3-benzoheteroepines (2a-g) containing group 15 (P, As, Sb, and Bi) and group 16 (S, Se, and Te) heavier elements were prepared by the reaction of the corresponding metal reagents with (Z,Z)-o-bis(beta-lithiovinyl)benzene (5) which was derived in two steps from a common o-phthalaldehyde (3). The heteroepines (2) thus obtained were thermally labile towards heteroatom extrusion, and their half-lives on heating estimated from (1)H-NMR spectral analysis showed that the 3-benzoheteroepines (2) were far less stable than the corresponding 1-benzoheteroepines (1). The 2,4-bis(trimethylsilyl)-3-benzoheteroepines (17) containing Sb, Bi, and Te were also prepared from o-diiodobenzene (9) in 6 steps and were found to be more stable than the corresponding C-unsubstituted heteroepines (2). 相似文献