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排序方式: 共有169条查询结果,搜索用时 593 毫秒
61.
62.
D. J. Byron A. S. Matharu S. N. R. Shirazi A. R. Tajbakhsh R. C. Wilson 《Liquid crystals》2013,40(3):645-652
Abstract Seventeen esters, derived from 4-n-alkoxy-3-fluorophenols and 4-(5-n-alkyl-2-thienyl)benzoic acids, have been prepared and their liquid crystal transition temperatures determined by thermal optical microscopy. On cooling the isotropic liquid, the SA-SC-SA sequence of phases reported for the octyloxy-octyl and octyloxy-nonyl esters has been observed for certain other homologues, principally members of the 4-(5-n-nonyl-2-thienyl)benzoates. For these compounds, the temperature range of occurrence of the intermediate SC phase decreases as the length of the alkoxy chain increases (for the hexyloxy-nonyl to dodecyloxy-nonyl esters) and the Sc phase is absent for the tetradecyloxy-nonyl homologue. 相似文献
63.
Sodium hypochlorite, a cheap and readily available compound, when supported on silica gel can selectively oxidize benzylic and allylic alcohols to their carbonyl compounds in the presence of catalytic amount of DMSO. 相似文献
64.
Lasemi Zahra Tajbakhsh Mahmood Alinezhad Heshmatoallah Mehrparvar Forough 《Research on Chemical Intermediates》2020,46(7):3667-3682
Research on Chemical Intermediates - 1,8-Diazabicyclo [5.4.0] undec-7-ene functionalized cellulose nanofibers (CNF@DBU[Cl]) were simply prepared and characterized by analytical techniques. Scanning... 相似文献
65.
R. Baharfar M. Tajbakhsh A. Hamedaninejad S.J. Hosseini 《中国化学快报》2008,19(2):175-179
The addition of α-keto amides as a NH-acid to alkyl propiolates and dialkyl acetylenedicarboxylates in the presence of a catalytic amount of triphenylphosphine gives the corresponding substituted alkyl acrylates. 相似文献
66.
Yuan Li Jeung-yil Park Riki Shiroma Masakazu Ike Ken Tokuyasu 《Applied biochemistry and biotechnology》2012,166(7):1781-1790
A mutant Cs3512, which showed better fermentation of xylose and the mixtures of xylose and glucose, was obtained through mutation
of Candida shehatae ATCC 22984 and screening with a medium containing antimycin A and TTC (2,3,5-triphenyltetrazolium chloride). Cs3512 produced
44.4 g/l of ethanol from 121.3 g/l of xylose, which was 13% higher than that by ATCC 22984. At the same time, xylitol production
was reduced by 38% to 10.2 g/l from 16.3 g/l by ATCC 22984. Cs3512 also showed 8% increase in ethanol yield from 0.39 to 0.42 g/g
comparing to ATCC 22984 when fermenting the sugar mixture composed of 52.9 g/l glucose and 21.2 g/l xylose. When Cs3512 was
used in the simultaneous saccharification and fermentation of lime pretreated rice straw via CaCCO (calcium capturing by carbonation)
process, it produced ethanol at 77% of the theoretical yield. The results imply that Cs3512 is a potential non-recombinant
yeast strain for ethanol production from lignocellulosic biomass. 相似文献
67.
A heteropolyacid efficiently catalyzed the cyclocondensation reaction of 2-aminobenzamide and salicylamide with aldehydes and ketones to afford good yields of benzoxazine and quinazoline ring systems in an aqueous medium. The method gives clean reactions, has simple workup procedure, and uses environment friendly conditions. 相似文献
68.
AbstractAnchoring 1-methyl-3-(triethoxysilylpropyl) imidazolium chloride onto silica-coated magnetic Fe3O4 particles afforded the corresponding supported ionic liquid. Exchanging the Cl? anion by treating with H2SO4 gave Brønsted ionic liquid 1-methyl-3-(triethoxysilylpropyl) imidazolium hydrogensulfate. The synthesized catalyst was characterized by various techniques such as infrared, x-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and elemental analyses. The results indicated that the prepared catalyst had a nanostructure. The catalytic activity of the supported ionic liquid was examined in the synthesis of the polysubstituted pyridines by reaction of aromatic aldehydes with acetophenones and ammonium acetate in moderate to good yields under solvent-free conditions. The catalyst can be easily recovered by applying an external magnetic field and reused for at least seven runs without deterioration in catalytic activity. 相似文献
69.
Yaghoub Sarrafi Mahmood Tajbakhsh Rahman Hosseinzadeh Marzieh Sadatshahabi Kamal Alimohammadi 《合成通讯》2013,43(5):678-685
Benzylic C-H oxidation of a wide variety of alkyl- and cycloalkyl arenes employing 2,6-dicarboxypyridinium fluorochromate under mild reaction conditions is described. The corresponding carbonyl compounds are obtained in good to excellent yields. 相似文献
70.
Mahmood Tajbakhsh Ardeshir Khazaei Majid Shabani Mahalli Ramin Ghorbani Vaghi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1159-1163
N,N-Dibromobenzenesulfonamide(dibromoamine-B), which is prepared easily in high yield, has been employed as effective brominating agent for carbanionic substrates under mild conditions. β-Diketones and β-ketoesters were brominated by this reagent without using any bases. The reagent can be recovered, rebrominated, and reused several times. 相似文献