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81.
82.
We have obtained novel photosensitive materials containing a semiconductor photocatalyst and a dye sensitizer. We have studied the activity of the latter in the reaction of photoreduction of methylene blue, and we consider possible mechanisms for the photocatalytic effect. 相似文献
83.
84.
85.
A thermal analysis study on the reduction of iron oxide rich slags under different conditions is presented in this paper. The effects of important process variables such as time, temperature, lime-silica ratio, FeO level in slag etc. are discussed. It is shown that the mechanism of reduction by externally added graphite is different from that by a carbon saturated bath although the activation energy values are similar. 相似文献
86.
采用溶胶凝胶法,以蔗糖和正硅酸乙酯(TEOS)为原料,草酸为TEOS水解的催化剂,制备均相碳化硅前驱体,在氩气氛和高温条件下(1 350~1 600 ℃)将碳化硅先驱体进行碳热还原,制备出高比表面积的SiC。考察了水/TEOS物质的量的比、碳/硅物质的量的比及镍盐等因素对碳化硅比表面积的影响。结果表明,当nwater/nTEOS=7.5,nC/nSi=4时,适宜的镍催化剂(nNi/nTEOS=0.005),凝胶形成的时间最短,镍盐的加入可使碳热还原温度降低200 ℃。 相似文献
87.
KEIKO TAKAHASHI HIDEKI YOKOMIZO KATSURO ISHIYAMA MASAHIKO KITSUTA MEGUMI OHASHI 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):95-99
Asymmetric reduction of indol-3-pyruvic acid (IPA) with NaBH4 in aqueous solution in the presence of various cyclodextrins (α-, β-, γ-, mono-6-amino-6-deoxy-β- and di-6ABamino-6AB-deoxy-β-cyclodextrin) was investigated. From the NMR and circular dichroism spectral studies, the conformation of the CyD–substrate complexes is suggested; the part of carboxylic group stay in the cavity of α-CyD, whole of IPA in β-CyD, two molecules in a γ-CyD cavity, and IPA(s) is/are on the rim of the cavity of mono-6-amino-6-deoxy-β- and di-6ABamino-6AB-deoxy-β-CyD (AβCyD, DAβCyD) with electrostatic interaction between amino group and carboxylic group. This conformational difference provides in the difference in the optical selectivity of reduction. 相似文献
88.
Wei-Chieh YangXin-An Lu Suvarn S KulkarniShang-Cheng Hung 《Tetrahedron letters》2003,44(42):7837-7840
A triethylsilane-reductive etherification of the trimethylsilyl ethers with a variety of carbonyl compounds in good yields at room temperature employing 0.5 mol% Cu(OTf)2 as an extremely efficient catalyst is described here. 相似文献
89.
The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO2 composite films is investigated. The composite film was prepared on glass fiber with the water glass as binders and dilute
H2SO4 solution as solidifying reagent. The surface characters were observed by scanning electron microscope. The photocatalytic
degradation of aniline on the composite films was carried out in a TiO2/UV system. Some important factors affecting the photodegradation, such as the concentration of TiO2, the initial concentration of aniline, and the existing water vapor, are also studied. The product of photocatalytic oxidation
was detected by Fourier transform-Infrared. The partial intermediate products were absorbed on TiO2 surface, which resulted in catalyst deactivation. But when it was irradiated under UV illumination or solar irradiation for
some time, the catalyst could be reused without loss of catalytic activity.
Translated from the Journal of Wuhan University (Natural Science Edition), 2005, 51(2) (in Chinese) 相似文献
90.
V. D. Sheludyakov Z. V. Belyakova V. M. Shevchenko E. A. Chernyshev 《Russian Chemical Bulletin》1997,46(5):997-1002
Novel dialkylaminocarbenium salts with metallocomplex counter ions were prepared by the reaction of phosgene with either DMF
or tetramethylurea in the presence of metal chlorides. Reactions of organosilicon amides with phosgene gave corresponding
carbenium salts, while organosilicon ureas yielded aminoiminocarbenium salts. Dialkylaminochlorocarbenium salts were reduced
with hydrosilanes to give dialkylaminocarbenium, salts and can be easily hydrolyzed to afford either amides or ureas. Pathways
of the reaction with water and alcohols depend on the nature of reagent and the reaction conditions.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1035–1040, May 1997. 相似文献