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排序方式: 共有238条查询结果,搜索用时 125 毫秒
81.
We studied adsorption characteristics of a series of LTA zeolite as an adsorbent for desulfurization of propylene, that was
produced from bioethanol by ethanol-to-olefin (ETO) conversion. A breakthrough curve (BTC) for adsorption of methanethiol,
as one of the sulfur impurities of propylene produced from bioethanol, in the presence of propylene was measured using a fixed-bed
column packed with the LTA zeolite. The BTC revealed that the effect of the competitive adsorption of propylene on the LTA
zeolite strongly depended on a cation species exchanged in the micropores of the zeolite. Among the cation species examined
in this study, bivalent cation of zinc (Zn2+) was proved to be the most effective one to increase the amount of methanethiol adsorbed on the LTA zeolite under the presence
of propylene. The specific interaction of methanethiol with the LTA zeolite exchanged with Zn2+ was confirmed by the measurement of a temperature-programmed desorption (TPD) spectrum of methanethiol. 相似文献
82.
S Stadlbauer K Ohmori F Hattori K Suzuki 《Chemical communications (Cambridge, England)》2012,48(67):8425-8427
Concise synthesis of (-)-epicatechin and its 3-O-gallate is described, illustrating efficacy of the new strategy for catechin-class polyphenols based on assembly of lithiated fluorobenzene and epoxy alcohol followed by a pyran cyclization. 1,3,5-Trifluorobenzene serves as the A-ring equivalent for functionalization and the pyran annulation. 相似文献
83.
T Yano K Ohmori H Takahashi T Kusumi K Suzuki 《Organic & biomolecular chemistry》2012,10(38):7685-7688
A catechin hetero-trimer isolated from Ziziphus jujuba has been synthesized. Among three constituent monomers, (-)-epiafzelechin and (-)-epigallocatechin were prepared by de novo synthesis. Trimer formation relied on the unified approach to oligomers based on the bromo-capping and the orthogonal activation, reaching the reported structure of the natural product. 相似文献
84.
Kohei Azami Taiki Hayashi Takenori Kusumi Ken Ohmori Keisuke Suzuki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5375-5380
The first total synthesis of carthamin ( 3 ), a historic natural red pigment, has been achieved. The molecular structure was efficiently constructed by assembling two equivalents of the in situ generated lithiated monomers and triisopropyl orthoformate. This synthesis confirms the structure proposed in 1996. 相似文献
85.
Apiluck Eiad-ua Takuji Yamamoto Takao Ohmori Wiwut Tanthapanichakoon Tawatchai Charinpanitkul 《Journal of Non》2009,355(50-51):2508-2513
Carbon-coated silica gel beads could be prepared by immersing porous silica gel beads in a resorcinol–formaldehyde (RF) aqueous solution and then following by drying and pyrolysis in nitrogen atmosphere. With the proposed method, deposition of colloidal nanoparticles formed during the sol–gel polycondensation of the RF solution was successfully prepared on the mesopores of the silica gel beads. Both size and concentration of the colloidal particles could be controlled by the gelation time and the mixing ratio (VEtOH/VRF) of the RF solution to ethanol. The porous characteristics of the prepared carbon-coated silica gel beads and the amounts of deposited carbon could be controlled by changing VEtOH/VRF. Without any significant decrease in mesoporosity, the maximal carbon contents of carbon-coated silica gel beads could be increased up to 18 wt% in the inner part and 53 wt% on the outer surface, respectively. 相似文献
86.
87.
88.
F Suzuki T Kuroda H Hayashi Y Nakasato H Manabe K Ohmori S Kitamura 《Chemical & pharmaceutical bulletin》1992,40(12):3245-3252
A series of novel 3-substituted imidazo[4,5-c]quinolin-4(5H)-ones (2a-w) was prepared by the reaction of imidazo[4,5-c]quinolin-4(5H)-ones (6) with several electrophiles under basic conditions. The bronchodilatory activity of these compounds was evaluated on the basis of their protective effects against antigen-induced contraction (the Schultz-Dale reaction) of guinea-pig trachea (in vitro) and antigen inhalation-induced bronchospasm in passively sensitized guinea-pigs (in vivo). Although correlations between in vitro and in vivo activities were not clear, short alkyl chains such as the methyl and ethyl groups at the 3-position were important for potent activity, especially in vivo. Substituents at the 5-position were more tolerant of the activity than those at the 3-position. 5-Ethyl-3-methyl-3H-imidazo[4,5-c]quinolin-4(5H)-one (21) exhibits the most potent bronchodilatory activity among our tested compounds and is at least 5-fold more active than theophylline in vivo. 相似文献
89.
Susumu Yamamoto Katsushi Morimoto Toshiaki Sato 《Journal of heterocyclic chemistry》1991,28(6):1545-1547
A facile synthesis of 5 -chloropyrazoles 4a-e from 5 -aminopyrazoles 2a-e via diazotization followed by chlorodediazoniation is described. A new application of sulfur dioxide as a catalyst was demonstrated to be the best for the chlorodediazoniation of diazonium chlorides 3a-e . 相似文献
90.
Miyoko Suzuki Hidenobu Ohmori Marton Kajtar József Szejtli Maria Vikmon 《Journal of inclusion phenomena and macrocyclic chemistry》1994,18(3):255-264
OrangeII (4) and cyclodextrin (CD) form 2 : 1 and 2 : 2 complexes. The complexes self-associate and microscopy indicates the formation of a fibroid aggregate. In the induced c.d. spectrum, the * band of this complex appears at 500 nm in solution, but in the aggregate it changes to aJ-band due to the head-to-tail stacking of4 and aH-band due to its parallel stacking; this indicates that the aggregation expands not only in the direction of the symmetry axis of the CD, but also in the other two dimensions.2H-NMR spectroscopy from deuteron exchange and solvation between the aggregate and deuterium oxide exhibits quadrupole splitting in the region of 0–0.2 KHz. The orientation behavior obtained from this splitting suggests the formation of a liquid-crystaloid substance.13C-T
1 NMR indicates that molecules4 and CD show the sameT
1 values even at 333 K; this complex behaves like a single molecule. The behaviors of other azo dye-CD complexes are also discussed.DeceasedDedicated to Professor József Szejtli. 相似文献