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971.
972.
Dissociation rates of N2 in N2-H2 mixtures and of H2 in Ar-H2 mixtures have been calculated for conditions typical of gas discharges. The results have been obtained by solving a system of master equations including V-V (vibration-vibration), V-T (vibration-translation) and e-V (electron-vibration) energy exchanges. The results show that these rates are much smaller than the corresponding ones for pure gases, as a consequence of the increased importance of V-T processes. A simplified model, which takes into account the main features of the distribution of vibrational levels in an electrical discharge, has been built up to rationalize the present results as well as those derived in our previous work. 相似文献
973.
A. B. Trofimov B. A. Trofimov N. M. Vitkovskaya M. V. Sigalov 《Chemistry of Heterocyclic Compounds》1991,27(6):583-590
The electron and conformational structures, as well as the internal rotation, of 2-(2-furyl)pyrrole and its -protonated forms were studied by the MNDO method with complete optimization of the geometry. In conformity with the experiments (PMR), the two delocalized cations with a cis orientation of the heteroatoms that are formed as a result of protonation of the pyrrole or furan ring have the greatest and virtually equal stabilities (H=738.7 and 740.6 kJ/mole).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 746–753, June, 1991. 相似文献
974.
V. M. Rogovik N. I. Delyagina E. I. Mysov V. F. Cherstkov S. R. Sterlin L. S. German 《Russian Chemical Bulletin》1990,39(9):1879-1882
-Fluorosulfatoperfluoroethyl isopropyl ketone I and fluorosulfatopentafluoroacetone II react with alkali metal chlorides and bromides to form the corresponding -haloperfluoro ketones as a result of direct nucleophilic substitution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2066–2069, September, 1990. 相似文献
975.
976.
977.
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979.
Bernard A. Mikrut Krishan K. Khullar Pamela Y. P. Chan John M. Kokosa Ludwig Bauer Richard S. Egan 《Journal of heterocyclic chemistry》1974,11(5):713-718
The reaction of pyridine 1-oxide with 1-adamantanethiol in acetic anhydride produced a mixture of 2- and 3-(1-adamantanethio)pyridines, 1-aeetyl-2-(1-adamantanethio)-3-hydroxy-4-acetoxy-1,2,3,4-telrahydropyridine and the corresponding 3-acetoxyderivative. Pure substances were separated by means of column chromatography on alumina. The tetrahydropyridines were identified by means of their proton magnetic and mass spectra. 4-(1-Adamantanethio)pyridine was synthesized from 4-chloropyridinc and 1-adamantanethiol. The three isomeric (1-adamantanethio)-pyridines were, each, cleaved by concentrated hydrochloric acid to give 1-chloroadamantane and the corresponding pyridinethiol. 相似文献
980.