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41.
Klose BS Jentoft FC Schlögl R Subbotina IR Kazansky VB 《Langmuir : the ACS journal of surfaces and colloids》2005,21(23):10564-10572
Sulfated zirconia (SZ) and sulfated zirconia promoted with 2 wt % manganese (MnSZ) or iron (FeSZ), all active in n-butane isomerization, were investigated using diffuse reflectance Fourier transform IR spectroscopy (DRIFTS). By adsorption of H(2) at 77 K or of n-butane at room temperature, it was found that the promoters neither enhance the Lewis nor the Br?nsted acid strength. SZ and promoted SZ do not exhibit higher acid strength than zeolites. In a batch experiment using 70 hPa of H(2), SZ did not react at 473 K. Reaction of H(2) with MnSZ produced water (band at 5242 cm(-1)) and a decrease in the sulfate groups (multiple bands). Heating of SZ in 10 hPa n-butane to 573 K caused total reduction of sulfate to H(2)S (2583, 2570 cm(-1)) and partial and total oxidation of butane to olefinic species (3062 cm(-1)), CO(2), and water. MnSZ and FeSZ reacted with n-butane already at 373 K; products of skeletal isomerization (methyne CH vibration at 2910 cm(-1)) were detected and sulfate groups were consumed. Rather than increasing the acidity, the promoters enhance the oxidation potential of sulfate and facilitate alkane activation via oxidative dehydrogenation. 相似文献
42.
Dr. Ivan A. Yaremenko Peter S. Radulov Yulia Y. Belyakova Arina A. Demina Dmitriy I. Fomenkov Dr. Denis V. Barsukov Dr. Irina R. Subbotina Prof. Fabrice Fleury Prof. Alexander O. Terent'ev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(21):4734-4751
The catalyst H3+xPMo12−x+6Mox+5O40 supported on SiO2 was developed for peroxidation of 1,3- and 1,5-diketones with hydrogen peroxide with the formation of bridged 1,2,4,5-tetraoxanes and bridged 1,2,4-trioxolanes (ozonides) with high yield based on isolated products (up to 86 and 90 %, respectively) under heterogeneous conditions. Synthesis of peroxides under heterogeneous conditions is a rare process and represents a challenge for this field of chemistry, because peroxides tend to decompose on the surface of a catalyst . A new class of antifungal agents for crop protection, that is, cyclic peroxides: bridged 1,2,4,5-tetraoxanes and bridged ozonides, was discovered. Some ozonides and tetraoxanes exhibit a very high antifungal activity and are superior to commercial fungicides, such as Triadimefon and Kresoxim-methyl. It is important to note that none of the fungicides used in agricultural chemistry contains a peroxide fragment. 相似文献
43.
Optimal control problems with a terminal pay-off functional are considered. The dynamics of the control system consists of rapid oscillatory and slow non-linear motions. A numerical method for solving these problems using the characteristics of the Hamilton–Jacobi–Bellman equation is presented. Estimates of the accuracy of the method are obtained. A theorem is proved which enables one to determine the class of functions containing the optimal preset control to be obtained. The results of the numerical solution of a terminal optimization problem for a fast non-linear pendulum are presented. 相似文献
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E. V. Borisov L. E. Kholodov A. A. Bagatur'yants O. A. Subbotina V. G. Yashunskii 《Chemistry of Heterocyclic Compounds》1970,6(11):1357-1364
A number of sydnone and sydnonimine derivatives were calculated by the simple Huckel method with Pullman parameters. Several physical characteristics of the molecules are compared with the calculated data.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1456–1464, November, 1970. 相似文献
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Shafran Y Rozin Y Beryozkina T Zhidovinov S Eltsov O Subbotina J Leban J Novikova R Bakulev V 《Organic & biomolecular chemistry》2012,10(30):5795-5798
Novel self-condensation of 3-(azol-5-yl)-1,1-dimethylenamines has been found to form new C-C bonds leading to 2,4-(1,2,3-triazole-1,2,3-thiadiazole-3-phenylisothiazole)-(1E,3Z)-5-yl-butadiene-1-amines. The discovered reaction represents a new example of C-H functionalization in unsaturated systems and can serve an efficient synthetic approach to rational design of new 2,4-(diazole-5-yl)-dieneamines. 相似文献
50.
Nataliya P. Belskaya Vasiliy A. Bakulev Julia O. Subbotina Wim Dehaen Koen Robeyns 《Tetrahedron》2009,65(36):7662-5307
Reaction of 3-alkylsulfanyl-2-arylazo-3-(pyrrolidin-1-yl)acrylonitriles with maleimides, dimethyl maleate and dimethylacetylene dicarboxylate were carried out to give octahydro-pyrrolo[3,4-a]pyrrolizin-4-ylidenes, hexahydro-pyrrolizines and 6,7-dihydro-5H-pyrrolizines. The formation of the synthesized compounds is explained by a 1,3-dipolar cycloaddition of an in situ generated azomethine ylide. The mechanisms of the formation of these active intermediates were discussed with the aid of density functional theory methods with the B3LYP functional 6-31G+ calculations using the STQN method and chemical experiments. 相似文献