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Grigorenko G. M. Adeeva L. I. Tunik A. Yu. Korzhik V. N. Doroshenko L. K. Titkov Ye. P. Chaika A. A. 《Powder Metallurgy and Metal Ceramics》2019,58(5-6):312-322
Powder Metallurgy and Metal Ceramics - The structure and phase composition acquired by coatings deposited in optimum mode by the plasma arc spraying process were examined. The spraying materials... 相似文献
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Isotopic analysis ofn-butane isomerization over sulfated zirconium oxide, using double13C-labelledn-butane, shows that at low temperature this isomerization is an inter-molecular process. Probably, a C8 surface intermediate is formed which isomerizes and undergoes -fission; the iso-C4 fragments are desorbed asi-butane. Previously, the same mechanism was indicated for Fe, Mn promoted catalysts. The isomerization rate at 130°C is drastically lowered by gaseous H2, because the concentration of the unsaturated species, required for the formation of the C8 intermediate, is low under such conditions. Whereas13C-scrambledi-butane is a true primary product, isotopic scrambling ofn-butane continues after chemical equilibrium betweenn-butane andi-butane has almost been reached; i.e.13C scrambledn-butane is a secondary product. Intra-molecular rearrangement of carbon atoms inn-butane precedes intermolecular scrambling. The similarity of the isomerization mechanism over unpromoted sulfated zirconia and Fe, Mn promoted sulfated zirconia is paralleled by an equal strength of the acid sites in both catalysts. The shift in the FTIR band of CO adsorbed on the Lewis sites indicates that these sites, presumably surface Zr4+ ions, are weaker acids than A13+ in dehydrated alumina. 相似文献
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Adeeva Valeria Liu Hai-Yang Xu Bo-Qing Sachtler Wolfgang M.H. 《Topics in Catalysis》1998,6(1-4):61-76
Some solid acids, including sulfated zirconia and certain industrial isomerization catalysts, catalyze two types of n-butane isomerizations, avoiding primary carbenium ions or carbonium ions: (1) an internal rearrangement of the C atoms in n-butane and (2) skeletal isomerization of n-butane to iso-butane. No superacid sites are required for these reactions. The skeletal isomerization is an intermolecular reaction, involving a C8 intermediate. Easily accessible Brønsted acid sites and small amounts of olefin are crucial. Spectroscopic examination of the acid sites on sulfated zirconia shows that they are not stronger than the acid sites in zeolites such as HY. The butane isomerization rate is suppressed by CO, even when no CO is adsorbed on Lewis sites; formation of oxocarbenium ions is likely. The decisive role of Brønsted acid sites is demonstrated by results on deuterated catalysts. 相似文献
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Yu. S. Borisov A. L. Borisova L. I. Adeeva A. Yu. Tunik A. N. Burlachenko V. L. Rupchev 《Welding International》2013,27(4):306-310
Special features of the production of powders for thermal spraying by mechanical alloying and mechanochemical synthesis are described. 相似文献
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Puzhel A. O. Borisov V. A. Osipov A. R. Petlin I. V. Kiselev A. D. Adeeva L. N. 《Russian Journal of Non-Ferrous Metals》2021,62(2):174-178
Russian Journal of Non-Ferrous Metals - A spent cracking catalyst (SCC) containing 1 wt % of rare-earth-elements (REEs) oxides is proposed as an alternative raw material to obtain REEs. We have... 相似文献
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