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51.
Yotaro Morishima Shigeki Nomura Mikiharu Kamachi 《Journal of polymer science. Part A, Polymer chemistry》1994,32(16):3141-3146
3,7-Diethyl- 10-phenylphenothiazine (DEPPT), a phenothiazine derivative whose 3,7- and 10-positions are blocked, was synthesized. Potentiostatic electrolysis of DEPPT in acetonitrile (ACN) in the presence of 0.1M of LiClO4 at 0.7 V (vs. Ag/Ag/Cl) yielded the stable cation radical of DEPPT (DEPPT+·) which was characterized by cyclic voltammetry, UV-visible spectroscopy, and ESR spectrometry. Stable cation radicals of 10-phenylphenothiazine and 3,7-diethyl-10-methylphenothiazine were also prepared. The cationic polymerization of n-butyl vinyl ether was initiated by these cation radicals, including DEPPT·+. The electron transfer mechanism for the initiation step, which we proposed previously, was supported by the fact that DEPPT·+ was capable of initiating the polymerization; dimerization of DEPPT·+ by releasing protons is precluded because 3,7- and 10-positions are all blocked. © 1994 John Wiley & Sons, Inc. 相似文献
52.
Masao Tomoi Noriyuki Yanai Satoshi Shiiki Hiroshi Kakiuchi 《Journal of polymer science. Part A, Polymer chemistry》1984,22(4):911-926
Polymer-supported crown ethers were prepared from chloromethylated or ω-bromoalkylated polystyrene resins and hydroxymethylbenzo-18-crown-6 and 15- or 18-membered monoazacrown ethers. Effects of the cavity size of crown ethers, the degree of crosslinking, the degree of ring substitution, particle size, spacer chains, and solvents on the activity of the polymer-supported crown ethers in the reaction of 1-chloro- or 1-bromo-octane with aqueous NaI or KI were investigated and mechanisms of the reaction were discussed in terms of mass transfer, intraparticle diffusion, and intrinsic reactivity. 相似文献
53.
Masao Ikeda Takashi Nakamura Yu Nagase Koji Ikeda Yoshiro Sekine 《Journal of polymer science. Part A, Polymer chemistry》1981,19(10):2595-2607
For the purpose of studying the mechanism of thermal degradation of poly[(tetramethyl-p-silphenylene) Siloxane] (poly TMPS) a series of polymers with silphenylene and siloxane bonds in the main chain were prepared and subjected to thermogravimetry (TG) and pyrolysis study. Analyses of products from poly TMPS degradation (in vacuum at a constant temperature) by gas chromatography (GC), infrared (IR), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) revealed that degradation occurs at the silphenylene bonds. The TG curves obtained in He for heating rates of 1,2,2.5,7.5, and 10°C/min were analyzed by the Ozawa method; activation energies of 39 ± 1 and 45 ± 2 kcal/mol were obtained respectively for the initial cleavage of the methyl side group and the later-stage scission of the main-chain silphenylene bond which leads to a major weight loss. The results agree with those obtained for other structurally similar polymers. 相似文献
54.
Koichi Shiomi Masao Shimono Hiromi Arimoto Seiji Takahashi 《Journal of separation science》1991,14(11):729-737
A slightly modified, commercially available high resolution capillary gas chromatograph and a PC-based data processing system running proprietary software (“PONA”) have been employed in the development of a system for petroleum type analysis which would be equivalent or superior to the FIA (fluorescent indicator adsorption) method in terms of ease of use and the speed, variety, and accuracy of the analytical data produced. The system is capable of performing identification and quantitation of most of the individual components in a complex gasoline sample consisting of more than 230 components and can report weight percentage and/or volume percentage for each component as well as types by carbon number (e.g., isoparaffins, normal paraffins, olefins, naphthenes, aromatic compounds) within a ca. 70 minute analysis cycle. Precolumn sulfonation to trap olefins and aromatic compounds has been used as an complementary technique to the basic mass spectrometric identification of components of interest. The estimation of correction factors for weight percentage (or volume percentage) calculation are also discussed. Comparisons are made between this system and others, and the results indicate that the proposed method supersedes the conventional method employing FIA. 相似文献
55.
Serber Z Straub W Corsini L Nomura AM Shimba N Craik CS Ortiz de Montellano P Dötsch V 《Journal of the American Chemical Society》2004,126(22):7119-7125
Studying protein components of large intracellular complexes by in-cell NMR has so far been impossible because the backbone resonances are unobservable due to their slow tumbling rates. We describe a methodology that overcomes this difficulty through selective labeling of methyl groups, which possess more favorable relaxation behavior. Comparison of different in-cell labeling schemes with three different proteins, calmodulin, NmerA, and FKBP, shows that selective labeling with [(13)C]methyl groups on methionine and alanine provides excellent sensitivity with low background levels at very low costs. 相似文献
56.
An epoxy-group-containing polymer chain was grafted onto the hollow-fiber form of a porous polyethylene membrane by the immersion of the electron beam-irradiated trunk polymer in glycidyl methacrylate diluted with methanol and 1-butanol. The epoxy group density ranged from 8.5 to 13.4 mol per kg of the trunk polymer. Subsequently, the epoxy groups produced were converted into sulfonic acid and diethylamino groups. The density of -SOH and -N(C2H5), groups was 0.40 and 2.2 mol per kg of the product. respectively. The polymer brush, defined as a polymer chain extending from the surface of a pore toward the interior of the pore, was evaluated from the determination of an equilibrium binding capacity of hen egg lysozyme (HEL) and bovine serum albumin (BSA). The polymer brush prepared in 1-butanol was found to be longer than that prepared in methanol from the determinations of liquid permeability and protein adsorptivity. The proteins were bound to the polymer brush prepared in 1-butanol, followed by the functionalization, at higher degrees of multilayer binding: about 30 for HEL and 6 for BSA. 相似文献
57.
Meso and racemic isomers of 1,1′-bis(α-hydroxyalkyl)ferrocene derivatives, and trans and cis isomers of 7-oxa[3]ferrocenophanes have been isolated. The configurations of these isomers have been determined both by spectroscopy and from their reaction behavior. It has been found that the ring-closure and ring-opening interconversion reactions between 1,1′-bis(α-hydroxyalkyl)ferrocenes and 7-oxa[3]ferrocenophanes are stereospecific. PMR spectra of the diols and ethers have been examined at 100 MHz in CF3COOH, and the existence of α-[1′-(α-hydroxyalkyl)ferrocenyl]carbonium ions has been demonstrated in this acid. A mechanism for the various interconversion reactions is proposed on the basis of their stereospecific reactivity and from the PMR spectra of the carbonium ions. 相似文献
58.
Nomura S Itoh T Nakasho H Uno T Kubo M Sada K Inoue K Miyata M 《Journal of the American Chemical Society》2004,126(7):2035-2041
Highly conjugated monomers, 7,7,8,8-tetrakis(alkoxycarbonyl)quinodimethanes (methoxy (1a), ethoxy (1b), isopropoxy (1c), benzyloxy (1d), chloroethoxy (1e), and bromoethoxy (1f)), were synthesized. Recrystallizations of 1a, 1c, 1e, and 1f yielded two crystal forms (prisms (1a-A) and needles (1a-B), needles (1c-A) and plates (1c-B), prisms (1e-A) and plates (1e-B), and prisms (1f-A) and needles (1f-B)), which have different molecular packing modes by X-ray crystal structure analysis, indicating that the crystals are polymorphic. In the photopolymerizations of these monomer crystals in the solid state, 1a-A, 1e-A, and 1f-A polymerized topochemically to give crystalline polymers. For their thermal polymerizations in the solid state, in addition to 1a-A, 1e-A, and 1f-A, 1e-B and 1f-B polymerized, but polymers formed from the 1e-B and 1f-B were amorphous. The packing of quinodimethane molecules in the crystals was defined by four kinds of parameters, stacking distance (d(s)), the distance between the reacting exomethylene carbon atoms (d(cc)), the angles formed between the stacking axis and longer axis of the monomer molecule (theta(1)), and the shorter axis of the monomer molecule (theta(2)), and then the polymerization reactivity of these quinodimethanes in the solid state was discussed on the basis of these parameters. 相似文献
59.
Tadatomi Nishikubo Atsushi Kameyama Jun Yamashita Takahiro Fukumitsu Chika Maejima Masao Tomoi 《Journal of polymer science. Part A, Polymer chemistry》1995,33(7):1011-1017
The addition reaction of oxiranes ( 15a-d ) with carbon dioxide (CO2) was carried out using 1 mol % of soluble polymer-supported quaternary onium salts as catalysts under atmospheric pressure. The reaction of 15a-d with CO2 proceeded very smoothly to give the corresponding five-membered cyclic carbonates ( 16a-d ) in high yields at 90-100°C. The catalytic activity of the soluble polymer-supported quaternary onium salts was strongly affected by the following factors: kind of reaction solvent, degree of introduction of the pendant onium salt residues in the polymer chain, and type of alkyl group on the onium salts due to the balance between lipophilicity and steric hindrance of the onium salt residue. Furthermore, these soluble polymer-supported quaternary onium salts were found ordinarily to have higher catalytic activity than low molecular weight quaternary onium salts under the same reaction conditions. It was also found that the rate of reaction was proportional both to catalyst concentration and to oxirane concentration. © 1995 John Wiley & Sons, Inc. 相似文献
60.
Masao Matsuoka Tsuyoshi Matsuda June Tamaki Yoshifumi Yamamoto Chiaki Iwakura 《Research on Chemical Intermediates》2006,32(5):389-402
Laves-phase hydrogen storage alloy has a high potential for use as negative electrode material as alternative for the misch-metal-based
material. In order to improve the energy density and the rate capability of negative electrode, chemical and mechanical modification
of Lavesphase alloy with different stoichiometric ratios was carried out. Discharge capacity and high-rate dischargeabilty
was evaluated by electrochemical methods and the characterization of Laves-phase alloy was made by X-ray diffraction, SEM
observation and PCT measurement. The best result in discharge capacity could be obtained for stoichiometric Laves-phase alloy
with a composition of Zr0.9Ti0.1Ni1.1Co0.1Mn0.5V0.2Cr0.1 by boiling in 10 M KOH solution. On the other hand, the high-rate dischargeability was increased remarkably by introducing
mechanical grinding before alkali treatment. The cause for improved performance was discussed on the basis of thermodynamic
stability of metal hydride and changes in crystal structure and surface morphology influencing on diffusion coefficient and
diffusion path length of hydrogen. 相似文献