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991.
A. N. Startsev B. N. Kuznetsov Yu. I. Yermakov 《Reaction Kinetics and Catalysis Letters》1975,3(3):321-327
The influence of preparation and treatment conditions on the catalytic activity in propylene disproportionation has been studied on catalysts prepared by interaction of W(-C4H7)4 with SiO2. The influence of the prehydration temperature of silica gel and the temperature of the treatment of the catalyst with hydrogen has been found to be appreciable. Comparison between the activity of the catalysts and the average oxidation state of tungsten ions suggests that the oxidation state of tungsten ions in the active catalyst component is +4.
, W(-C4H7)4 SiO2 . . , , 4.相似文献
992.
O. S. Anisimova Yu. N. Sheinker R. M. Palei P. M. Kochergin V. S. Ponomar' 《Chemistry of Heterocyclic Compounds》1975,11(8):982-984
The closeness of the electronic structures of the ions formed in the first act of disintegration of the ions is responsible for the monotypic character of the subsequent fragmentation of pyrrolo[1,2-a]benzimidazole and imidazo[1,2-a]benzimidazole derivatives. The mass-spectrometric disintegration of the investigated systems has something in common with the fragmentation of thiazolo[3,2-a]benzimidazole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1124–1127, August, 1975. 相似文献
993.
When dissolved in SbF5, polyfluorinated trifluoromethylbenzenes produce polyfluorinated α,α-difluorobenzyl ions. The 19F chemicals shifts and spin-spin coupling constants J(FF) have been analysed in terms of the resonance structures which contribute to the overall positive charge distribution. The influence of halogen atoms situated at position 4 on the downfield signal shift of α-fluorines follows the sequence F > Cl > Br which is opposite to that observed for 4-XC6H4CF2+ ions. 相似文献
994.
A. Ya. Strakov M. V. Petrova N. N. Tonkikh A. I. Gurkovskii Yu. Popelis G. P. Kreishman S. V. Belyakov 《Chemistry of Heterocyclic Compounds》1997,33(3):321-332
The reactions of 2-acetyldimedone and 2-acetyl-3-methoxy-5,5-dimethylcyclohex-2-en-1-one with 3,4-diaminobenzophenoneproduce2-[1-(2-amino-5-benzoylphenyl)amino]ethylidene-5,5-dimethyl-1,3-cyclohexanedioneand 2-acetyl-3-(2-amino-5-benzoylphenyl)amino-5,5-dimethylcyclohex-2-en-1-one, which are cyclized by the action of hydrochloric acid, yielding the respective hydrochlorides of 8-benzoyl- and 7-benzoyl-3,3,11-trimethyl-2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-2-ones. Hydrolytic cleavage of the 8-benzoyl derivative leads to 2-acetyl-3-(2-amino-4-benzoylphenyl)amino-5,5-dimethylcyclohex-2-en-1-one. A similar cleavage to form 2-acetyl-3-(2-aminophenyl)amino-5,5-dimethylcyclohex-2-en-1-one is observed for the known hydrochloride of 3,3,11-trimethyl-2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-2-one. The structures of the products were confirmed by PMR spectra and x-ray diffraction data.Riga Technical University, Riga LV-1658. Latvian Institute of Organic Chemistry, Riga LV-1006. University of Cincinnati, Ohio, USA. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 379–391, March, 1997. 相似文献
995.
V. P. Litvinov Yu. A. Sharanin M. P. Goncharenko V. D. Dyachenko A. M. Shestopalov 《Russian Chemical Bulletin》1991,40(8):1675-1681
The reaction of 3-cyano-1,4-dihydropyridine-2-thiolates and the corresponding selenolates with allyl bromide gave 2-allylthio- and 2-allylseleno-3-cyano-1,4-dihydropyridines, which, upon heating in various solvents or in the solid state, undergo [3,3]-sigmatropic rearrangement to give 3-cyano-3-allyl-1,2,3,4-tetrahydropyridine-2-thiones and the corresponding selenones. The resultant pyridinethiones are alkylated by alkyl halides at the sulfur atom and are oxidized by iodine to give disulfides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1888–1895, August, 1991. 相似文献
996.
V. V. Zakharov G. P. Bugaeva N. Yu. Andreeva L. B. Romanova L. T. Eremenko 《Russian Chemical Bulletin》1998,47(11):2226-2228
The reduction of 1-bromo-9,9-ethylenedioxypentacyclo[4.3.0.02,5.03,8.04,7]nonane-4-carboxylic acid (2) with lithium aluminum hydride and aluminum hydride in THF was studied. A new effective method for preparing 1-bromo-9,9-ethylenedioxypentacyclo[4.3.0.02,5.03,8.04,7]-non-4-ylcarbinol (1) based on reduction of2 with AlH3 under mild conditions was developed. 相似文献
997.
S. V. Fedorov A. Yu. Rulev N. N. Chipanina A. M. Shulunova V. G. Nenajdenko E. S. Balenkova D. A. Tyurin V. K. Turchaninov 《Russian Chemical Bulletin》2005,54(1):103-107
The molecular structures of β-amino-α-bromovinyl trifluoromethyl ketones was studied by UV, IR, 1H, 13C, and 15N NMR spectroscopy and using the density functional (B3LYP/6-31G(d,p) and PBE/QZ3P) and ab initio riMP2/cc-pVTZm quantum-chemical calculations. Factors affecting stabilization of the EZE-conformation of the molecules, which is atypical of analogous unsubstituted amino enones, are considered.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 102–106, January, 2005. 相似文献
998.
Yu. G. Ignat'ev 《Russian Physics Journal》1982,25(11):1063-1065
An exact solution of the equations of relativistic hydrodynamics is obtained for a semiinfinite ideal fluid with the equation of state =p in the field of a plane gravitational wave.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 99–102, November, 1982. 相似文献
999.
S. I. Sin'kov Yu. A. Sapozhnikov B. F. Myasoedov 《Journal of Radioanalytical and Nuclear Chemistry》1990,145(2):113-121
The interaction of short-lived Rn-daughter products /SLDP/, viz.214Pb and214Bi dissolved in sea-water with Fe/III/ hydroxide colloids followed by flotation of combined Fe-SLDP particles at the sea-air interface subsequently generating marine aerosols enriched in214Bi and214Pb have been studied under laboratory conditions. Rate constants for attachment of214Bi and214Pb to dispersed Fe/III/ colloids in the sea water are found to be 3.7×10–4 min–1 litre [g/Fe/]–1 and 2.4×10–4 min–1 litre [g/Fe/]–1, resp., /20°C/ over the concentration range of iron /III/ from 8 to 120 g liter–1. The suggested mechanism of colloid flotation and aerosol generation might be responsible for some peculiarities of SLDP distribution in the lower marine atmosphere. 相似文献
1000.
Ya. Yu. Stepanskii N. P. Evmenenko G. S. Yablonskii V. I. Bykov 《Reaction Kinetics and Catalysis Letters》1980,14(3):335-339
Self-oscillation found experimentally in the cool-flame combustion of a model n-heptane-i-octane mixture has been studied in dependence on the composition of the reaction mixture. Calculations based on the CSTR model are in qualitative agreement with experimental data.
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