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71.
72.
A kinetic study on methanol dehydrogenation over an FeTiZn0.44 alloy at 673 K suggested a mechanism including an adsorbed formaldehyde intermediate. A lower W/F and a higher methanol pressure favored a higher formaldehyde selectivity. 相似文献
73.
Synthesis of benzylidene-pendant polyphthalimidines from flexible bisphthalides and various diamines
Yoshio Imai Takeyoshi Takahashi Renzhi Nan Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》1983,21(5):1241-1249
New polyphthalimidine-forming monomers, 5,5′-(oxydi-p-phenylenedicarbonyl)bis(3-benzylidenephthalide) and the 6,6′-derivative, were synthesized by the Friedel–Crafts reaction of diphenyl ether with 5- and 6-chloroformyl-3-benzylidenephthalide, respectively. The direct polycondensation of these bisphthalides with both aliphatic and aromatic diamines in o-phenylphenol at 200–250°C afforded polyphthalimidines having inherent viscosities of 0.2–1.2 dL/g in almost quantitative yields. Syntheses of aliphatic polyphthalimidines with higher inherent viscosities were also achieved by a two-step procedure involving ring-opening polyaddition and subsequent thermal cyclodehydration. All the polymers were amorphous and readily soluble in N-methyl-2-pyrrolidone (NMP), m-cresol, nitrobenzene, pyridine, and chloroform. Tough and flexible films could be cast from NMP solutions of the polymers. Glass transition temperatures of the polyphthalimidines were in the range of 158–246°C. The thermogravimetry of the aromatic polymers showed 10% weight loss in air and nitrogen at 445–515 and 500–520°C, respectively. The crosslinking reaction of some benzylidenependant polyphthalimidines took place at 300°C through double-bond addition to afford cured polymers with improved thermal stability. 相似文献
74.
Takeo Saegusa Hirosuke Imai Shu-Ichi Matsumoto 《Journal of polymer science. Part A, Polymer chemistry》1968,6(3):459-465
Kinetic studies were carried out on the polymerization of tetrahydrofuran with catalyst systems of aluminum alkyl–epichlorohydrin. As aluminium alkyl species AlEt3, AlEt3–H2O (1:0.1 to 1:1.0), and “oxyaluminum ethyl” were employed. The polymerizations with these catalysts are characterized by a mechanism of stepwise addition without chain transfer or termination, which is expressed by the kinetic relation Rp = Kp[P*] ([M]–[M]e), where [M] and [M]e are the instantaneous and equilibrium concentrations of monomer and [P*] is the concentration of propagating species calculated from the amount and molecular weight of the product polymer. The determination of the rate constant kp for these catalysts has shown that the polymerization rate varied considerably with the change of aluminum alkyl species, i.e., with the water-to-aluminum ratio, but the propagation rate constant itself varied very little. The variation of polymerization rate was, therefore, attributed primarily to the differences in concentration of the propagating species, i.e. the efficiency of the catalyst in forming propagating species. The catalyst efficiency was closely related to the acid strength of the aluminum alkyl species, which was estimated from the magnitude of shift of the xanthone carbonyl band in the infrared spectrum of its coordination complex with aluminum alkyl. The maximal catalyst efficiency was attained at about [H2O]/[AlEt3] = 0.75. 相似文献
75.
A simple method is presented for measuring the heat of mixing and the heat of vaporization of volatile liquids at temperatures below their boiling point. It consists in introducing liquids by a microsyringe into a nearly closed cell of the DSC. The relative standard deviation for 4 to 5 runs is ca. 5% for heat of mixing and ca. 2% for heat of vaporization. 相似文献
76.
Masahiko Imai Lu Gong Xu Kazuo Ametani Mituaki Tutiya 《Journal of polymer science. Part A, Polymer chemistry》1989,27(5):1763-1773
Polypropylene films were irradiated with 60Co γ-rays in vacuum or in air and stored in air. Just after irradiation, the concentration of carbonyl group of the sample irradiated in air only increased with dose. The concentrations of both samples increased with storage time. The more the absorbed doses, the higher the increasing rates. The increasing rate of the concentration of carbonyl group during irradiation in air was higher than those during storage in air. Just after irradiation, the tensile strengths and the elongations of the both samples somewhat increased with dose at the doses less than 5 Mrad, but decreased at doses more than 13 Mrad. The tensile strength and the elongation of the sample irradiated in air decreased with storage time. Those of the sample irradiated in vacuum also decreased with storage time but the decreasing rates were much smaller than those in the sample irradiated in air. The gel fractions of the samples irradiated in vacuum and annealed in vacuum were somewhat higher than those irradiated in vacuum and not annealed. To elucidate high oxidation rate in the sample irradiated in air during and after irradiation, reaction mechanisms were discussed. To clarify the difference of mechanical properties between the samples irradiated in vacuum and in air, the effect of crosslink was considered, together with the oxidation. 相似文献
77.
Synthesis and analgesic activity of novel heterocycles, [1]benzothiopyrano[3,4-b]pyrrole derivatives
M Hori T Kataoka H Shimizu E Imai N Iwata N Kawamura M Kurono K Nakano M Kido 《Chemical & pharmaceutical bulletin》1989,37(5):1282-1286
In order to develop analgesic compounds possessing a sulfur atom in the alicyclic ring, novel cis-fused heterocycles, [1]benzothiopyrano[3,4-b]pyrrole derivatives (II) were synthesized via a unique cyclization reaction starting from 4-(4-methoxyphenylthio)-2-butanone (1) or 6-methoxy-3,4-dihydro-2H-1-benzothiopyran-4-one (7). The analgesic effects of benzothiopyranopyrroles (16, 18) were measured by means of the writhing test. The phenolic derivative 18 completely inhibited the appearance of writhing at the dose of 50 mg/kg, but the methoxy derivative 16 had no analgesic effect. 相似文献
78.
Masahiko Ogura Norikazu Nakatani Norisuke Yamaji Makoto Imai Akio Itoh Nobutsugu Imanishi 《Radiation Physics and Chemistry》1997,49(6):645-649
We have studied effects of added elements as well as defects on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5 at.% Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373 K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. 相似文献
79.
A Smart Sensing Method for Object Identification Using Circularly Polarized Luminescence from Coordination‐Driven Self‐Assembly 下载免费PDF全文
Yuki Imai Yuka Nakano Prof. Tsuyoshi Kawai Dr. Junpei Yuasa 《Angewandte Chemie (International ed. in English)》2018,57(29):8973-8978
The potential use of circularly polarized luminescence for object identification in a sensor application is demonstrated. New luminescence probes using pyrene derivatives as sensor luminophores were developed. (R,R)‐Im2Py and (S,S)‐Im2Py contain two chiral imidazole moieties at 1,6‐positions through ethynyl spacers (angle between spacers ca. 180°). The probe molecules spontaneously self‐assemble into chiral stacks (P or M helicity) upon coordination to metal ions with tetrahedral coordination (Zn2+). The chiral probes display neither circular dichroism (CD) nor circularly polarized luminescence (CPL) without metal ions. However, (R,R)‐Im2Py and (S,S)‐Im2Py exhibit intense chiroptical activity (CD and CPL) upon self‐assembly with Zn2+ ions. (R,R)‐Im2Py and (S,S)‐Im2Py with chemical stimuli‐responsibility allow sensing using the CPL signal as detection output, enabling us to discriminate between a signal from the target analyte and that from non‐target species. 相似文献
80.
Three novel naphthoquinone-based heterocyclic pigments, 2-methyl-3-[(1-methyl-1H-imidazol-2-yl)thio-1,4-naphthalenedione, (4-methyl-4H-1,2,4-triazol-3-yl)thio-1,4-naphthalenedione, and (1-methyl-1H-tetrazol-5-yl)thio]-1,4-naphthalenedione, are synthesized, and their optical properties in both solution and solid states are investigated. Depending on the heteroarylthio ring in the pigment, variation in optical properties is observed, e.g. characteristic colours for each pigment in the solution and solid states. The achiral pigment containing the 1-methyl-1H-tetrazol-5-yl ring exhibits a chiral space group and a CD signal in the solid state. 相似文献