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排序方式: 共有320条查询结果,搜索用时 187 毫秒
1.
A membrane filtration method was examined concerning the effective collection of iron(III) from a homogeneous aqueous solution with Chromazurol B (CAB), one of the triphenylmethane dyes, as a precipitating reagent in the presence of a non-ionic surfactant, polyethylene glycol mono[4-(1,1,3,3-tetramethylbutyl)phenyl]ether (Triton X-100). A formed blue Fe(III)-CAB complex was collected as a precipitate on a membrane filter by filtration under suction from a homogeneous aqueous solution in the pH range over about 2. The original solution was prepared at a concentration ratio of CAB to Fe(III) of to 10, and that of Triton X-100 to CAB of 10 to 100. It was then adjusted to a pH value of between 1.0 and 6.5. A linear relationship (r = 0.999) was obtained between the initial concentration and the found one of Fe(III) in the range of 2.0 x 10(-5) to 4.0 x 10(-4) mol dm(-3) at a fixed concentration ratio of CAB to Fe(III) of 3 and that of Triton X-100 to CAB of 20. This membrane filtration with CAB and Triton X-100 may be utilized for the separation of Fe(III) as a background species. 相似文献
2.
Y. Ihara H. Nakano J. Koga N. Kuroki 《Journal of polymer science. Part A, Polymer chemistry》1972,10(12):3569-3576
In order to investigate the mechanism of the asymmetric interaction between optically active polymers and small molecules, optically active copolymers of N-acrylyl L-amino acids(N-acrylyl-L -phenylalanine, N-acrylyl-L -tryptophan, and N-acrylyl-L -leucine, respectively) and N,N′-hexamethylene diacrylylamide were synthesized, and interaction of these polymers with the optical isomers of phenylalanine and tryptophan was investigated. In the interaction of these acidic polymers with amino acids performed at pH 5.0, significant difference in amount of adsorption between the D and L isomers of amino acids were observed, and the L form of amino acids was adsorbed preferentially. The interaction between optically active small molecules was also investigated: these results showed a similarity to the results for interaction between optically active polymers and amino acids. In some instances of asymmetric interaction the influence of hydrophobic interaction between a polymer and substrate was clearly perceived. The stereoselective effects on the asymmetric interaction are discussed. 相似文献
3.
Kazuhiro Endo Hideo Ihara Kazuhiro Watanabe Shun-Ichi Gonda 《Journal of solid state chemistry》1982,44(2):268-272
X-Ray photoelectron spectra of TiS3 with a one-dimensional structure were measured. TiS3 may be regarded as Ti4+(S2)2?S2? with pairs of S atoms (S2) and isolated S atoms. The spectra of the sulfur core-levels are assigned by comparison with those of TiS2, where all S atoms are largely separated. The binding energy of the S2 pairs is found to be 1.4 eV higher than that of the isolated S atoms, which is consistent with the larger negative charge of the isolated atoms. The structures of the valence band of TiS3 are discussed in terms of a molecular orbital scheme for the S2 pairs. 相似文献
4.
Keiichiro Fukumoto Masatoshi Chihiro Yuichi Shiratori Masataka Ihara Tetsuji Kametani Toshio Honda 《Tetrahedron letters》1982,23(29):2973-2976
Thermolysis of a benzocyclobutene derivative () prepared from norcamphor produced stereoselectively a tetracyclic compound (), which was converted to a lactone () having correct stereochemistry at C7, C8, C9, C11, C13, and C14 positions of (±)-klaineanone. 相似文献
5.
Keivan Esfarjani Yuichi Hashi Satoshi Itoh Sigeo Ihara Yoshiyuki Kawazoe 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,41(1):73-76
To study the thermodynamic and mechanical stability of toroidal isomers of C 240, we use a semi-empirical tight-binding theory and calculate their electronic structure, cohesive energy and vibrational spectra within the harmonic approximation. From these, we deduce their free energy at temperatures up to 1500K. The results are also compared to the isomer with icosahedral symmetry. Finally, we discuss within this approach, their stability and abundance. 相似文献
6.
(±)-1-Benzyl-3α-hydroxy-4β-methylamino-2-oxopyrrolidine (15) and its cis-isomer (16) were synthesised from 1-benzyl-4-ethoxycarbonyl-2,3-dioxopyrrolidine (2) in several steps. The former (15) was converted to 3-benzyl-6-methyl-2-oxo-3,6-diazabicyclo[3.1.0]hexane (17) with a mixture of triphenylphosphine, carbon tetrachloride and triethylamine. 相似文献
7.
8.
Ihara M Katsumata A Setsu F Tokunaga Y Fukumoto K 《The Journal of organic chemistry》1996,61(2):677-684
[Ni(cyclam)](ClO(4))(2)-catalyzed indirect electroreduction of olefinic bromides produced six-membered compounds in low to high yields. The synthetic intermediate 49 of Ipecac and Corynanthe alkaloids was obtained in 88% yield in a highly stereoselective manner. Lactam 66, the synthetic precursor of tacamonine, was prepared in 49% yield as a mixture of two diastereoisomers. The electrolysis of the bromoacetates gave the debrominated compounds in good yields. 相似文献
9.
Cis-fused bicyclo[6.4.0]dodecene 11 was converted into taxane BC ring system 21 in three steps; transformation of the phenylsulfonyl group to an alpha-hydroxy carbonyl group by the treatment with potassium hexamethyldisilazide (KHMDS) and triethyl phosphite under oxygen atmosphere, followed by reductive elimination of the hydroxyl group of alpha-ketol moiety, and inversion of ring juncture. Epimerization of the sulfonyl group of 11 was indispensable for the first oxidation process (17 --> 18) and the second oxidation of 12 leading to hydroxylation at the alpha-position of the carbonyl group proceeded with high regio- and stereoselectivity to give 13. On the other hand, reaction of the cross-conjugated compound 5 with KHMDS at 0 degrees C brought about a complete reorganization of molecular framework to provide the compound 7 in which the five-membered ring and the conjugated seven-membered ring were connected through a single bond. 相似文献
10.
Y. Goto K. Nakashima K. Mitsuishi M. Takafuji S. Sakaki H. Ihara 《Chromatographia》2002,56(1-2):19-23
Summary Poly(octadecyl acrylate) exists in a crystalline state at room temperature. This crystalline state was formed even after being
grafted onto silica through the terminal group of the polymer. When this polymer-grafted silica (Sil-ODAn) was used as a reversed phase liquid chromatography packing material, better selectivity for diastereomerized phenylethylamines
derivatized by (S)-(−)-(2,3-naphthalenedicarboximidyl)propionyl fluoride was observed at room temperature than was observed
for simple octadecylated silica (ODS). On the other hand, increasing temperature reduced the selectivity to be close to that
of ODS. Additional experiments showed the better selectivity derived from Sil-ODAn was due to both the highly-oriented structure of the polymer and the carbonyl-π interaction with the diastereomer. A theoretical
investigation of this carbonyl-π interaction is also described briefly. 相似文献