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721.
Hisashi Miyafuji Toshiki Nakata Katsunobu Ehara Shiro Saka 《Applied biochemistry and biotechnology》2005,124(1-3):963-971
The water-soluble (WS) portion obtained by supercritical water treatment of lignocellulosics was studied for its fermentability
to ethanol. A fermentation test of the WS portion showed it was not fermented to ethanol. Therefore, a wood characoal treatment
was applied to the WS portion to remove furan and phenolic compounds, which are thought to be the inhibitors to sugar fermentability.
It was found that treatment with wood charcoal can be effective at removing these inhibitors and improving the fermentability
of the WS portion without reducing the levels of fermentable sugars. 相似文献
722.
A new methanodithiomethano-bridged dibenzotrithionin (1) has been synthesized. The electrochemical oxidation of 1 and its analogous compound was studied by cyclic voltammetry. A new type of the sulfur extrusion of 1 was found in the reaction of 1 with concd H2SO4 or 2 equiv of NOPF6 and in its photochemical reaction. 相似文献
723.
Hisashi Morikawa Yoshinori Uwamino Toshio Ishizuka 《Fresenius' Journal of Analytical Chemistry》1990,336(3):210-214
Summary Rare earth elements (REEs) in yttrium oxide were determined by secondary ion mass spectrometry (SIMS) with high sensitivity. The calibration graph approach was employed with chemically prepared standards. Molecular ion interferences derived from the matrix components which limit the superior sensitivity of SIMS were successfully suppressed by an energy filtering technique. The detection limits of the elements ranged from 0.02 to 0.2 g·g-1. 相似文献
724.
[reaction: see text] The reaction of nitroso compounds with enolates, "the nitroso aldol reaction", occurs in high yield to generate alpha-hydroxyamino carbonyl compounds. Yields range from 42% to 98% with N-selectivity >99:1 from commercially available aromatic or aliphatic nitroso compounds and a variety of alkali metal or tin enolates. 相似文献
725.
Mitsuru Ueda Hisashi Hazome Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1976,14(5):1127-1135
Novel oxime-containing polyamides have been prepared by the ring-opening polyaddition of combinations of two benzobis[1,2]oxazinediones, 4,6-diphenylbenzo[1,2-d:5,4-d′]bis[1,2]oxazine-1,9-dione and 4,9-diphenylbenzo[1,2-d:4,5-d′]bis[1,2]oxazine-1,6-dione, with two aliphatic diamines in a polar aprotic solvent such as N-methyl-2-pyrrolidone. The polymerization was almost completed within a day at room temperature. These polymers had inherent viscosities in the range of 0.12–0.38 and were soluble in a wide range of solvents, including formic acid and hot m-cresol, as well as a number of polar aprotic solvents. All the polymers softened at a temperature ranging from 165 to 185°C. Thermal characterization of the polyamides by TGA and DTA showed polymer decomposition temperatures of about 240°C in air. 相似文献
726.
Yuya Yamashita Hisashi Matsui Koichi Ito 《Journal of polymer science. Part A, Polymer chemistry》1972,10(12):3577-3587
Bischloroformates of hydroxy-terminated poly(tetramethylene glycol) (PTG) and polystyrene (PSt) were prepared and used as the initiators for the anionic polymerization of α-pyrrolidone and ε-caprolactam in bulk at 30°C and 80°C, respectively. Initiation efficiency was sufficiently high to give well-defined nylon–PTG(or PSt)–nylon block copolymers. Both the yield and the viscosity of the block copolymer increased with polymerization time up to 50% conversion of the lactam. 相似文献
727.
Ultrafast analysis of oligosaccharides on microchip with light-emitting diode confocal fluorescence detection 总被引:2,自引:0,他引:2
We have developed a new method for the high-speed separation and high-sensitivity detection of complex oligosaccharides based on microchip electrophoresis (nu-CE) with light-emitting diode (LED) confocal fluorescence detection. Oligosaccharides labeled with 8-aminopyrene-1,3,6-trisulfonate (APTS) were found to strongly adsorb to the surface of polymethylmethacrylate (PMMA) microchips. Accordingly, three classes of major dynamic coating additives were systematically investigated, and cellulose derivatives were found to specifically suppress such adsorption and allow high-performance separation on PMMA chips. Additive concentration, buffer pH and applied field strength were found to be key factors in the high-performance separation& of APTS-labeled oligosaccharides on PMMA chips. Under optimal conditions, 15 oligosaccharides in dextrin hydrolysate can be separated within 45 s with an electrophoretic separation efficiency of over 400 000 theoretical plates per meter. The relative standard deviation (RSD) values of migration times of fourteen oligosaccharides were less than 0.50% between six different channels, and the detection limit for APTS-labeled glucose was about 1.98 x 10(-8) mol/L or 8.61 amol with a signal-to-noise ratio (S/N) of 3. The high speed, high efficiency and high sensitivity of this micro-CE-based method indicate that it can be widely applied to analysis of complex oligosaccharides. 相似文献
728.
Summary A reversed-phase chromatographic column suitable for the purification of chemically synthesized large oligodeoxyribonucleotides (oligo-DNA) was prepared. The specifications of this column are; the selected silica (Toyo Soda silica) with large pore size (at least 150 ) and small particle diameter (5 m desired) should be grafted only with monochloro alkylating reagent of long alkyl chain (sufficiently C18) so that the carbon content of the resultant packing material is 15–16%. Using this column, we could isolate the targeted large oligo-DNA (up to 50mer) in a large scale (75 g per one cycle) from the impurities in the reaction mixture formed during the automated synthesis by the phosphite method. 相似文献
729.
Scandium trifluoromethanesulfonate (triflate), which is commercially available, is a practical and useful Lewis acid catalyst for acylation of alcohols with acid anhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acid anhydrides of not only primary alcohols but also sterically-hindered secondary or tertiary alcohols. The method presented is especially effective for selective macrolactonization of omega-hydroxy carboxylic acids. 相似文献
730.
Shiraiwa T Saijoh R Suzuki M Yoshida K Nishimura S Nagasawa H 《Chemical & pharmaceutical bulletin》2003,51(12):1363-1367
To obtain optically active threo-2-amino-3-hydroxy-3-phenylpropanoic acid (1), (2RS,3SR)-2-benzoylamino-3-hydroxy-3-phenylpropanoic acid [(2RS,3SR)-2] was first optically resolved using (1S,2S)- and (1R,2R)-2-amino-1-(4-nitrophenyl)-1,3-propanediol as the resolving agents to afford (2R,3S)- and (2S,3R)-2 in yields of 73% and 66%, based on half of the starting amount of (2RS,3SR)-2. Next, the racemic structures of ammonium and some organic ammonium salts of (2RS,3SR)-2 were examined based on melting point, solubility, and infrared spectrum, with the aim of optical resolution by preferential crystallization. The benzylammonium salt of (2RS,3SR)-2 was suggested to exist as a conglomerate at room temperature, although it forms a racemic compound at the melting point. The optical resolution by preferential crystallization of the racemic salt afforded the (2R,3S)- and (2S,3R)-salts with optical purities of 90-97%. The (2R,3S)- and (2S,3R)-2 obtained from the purified salts were hydrolyzed by reflux in hydrochloric acid to give (2R,3S)- and (2S,3R)-1. 相似文献