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51.
The bromocyclization of 3-allylamino-5-phenyl-1,2,4-triazine gives 3-bromomethyl-7-phenyl-2,3-dibromo-1H-imidazo[1,2-b]-1,2,4-triazinium bromide, which is transformed into 3-methyl-7-phenylimidazo-[1,2-b]-1,2,4-triazine.Yekaterinburg Fire-Fighting Technical Institute, Ministry of Internal Affairs, Russian Federation, 620002 Yekaterinburg. Chelyabinsk State University, 454136 Chelyabinsk. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 110–111, January, 1998. 相似文献
52.
We have determined the differences in the parameters log A and E of the Arrhenius equations for the kinetic isotope effect (KIE) (c-C6H12/c-C6D12) and the 5/6 effect (c-C5H10/c-C6H12) in reactions of the C—H bonds of cycloalkanes with adamantyl (Ad+) carbocations (1-adamantanol in 92.8% H2SO4, 40-97 °C). We have established the compensation relations between log A and E for the kinetic isotope effect and the 5/6 effect for anthracene (AH+), hydroxymethyl (CH2OH+), Ad+ carbocations and the hypothetical "infinitely strong reagent," supporting a hydride transfer mechanism in such reactions. 相似文献
53.
The reactions of alkane and alkene oxidation with peroxynitrous acid (HOONO) in aqueous solution-gas phase systems were studied using a modified kinetic distribution method. The rate constants of oxidation of hydrocarbons (RH) were found to be unusual bell-shaped functions of the volume ratio between liquid and gas phases in a reactor. This result, as well as the previously found proportionality of the rate constants of the gas-phase RH + HOONO and RH + OH· reactions for alkanes, alkenes, and alkylbenzenes, was quantitatively interpreted assuming the rapid equilibrium distribution of HOONO and RH between a gas and a solution, the formation of OH· radicals in the two phases, and the interaction of these radicals with RH. The rate constant of peroxynitrous acid decomposition in the gas phase and the distribution coefficient of this acid between the gas phase and solution α = (0.4–2) × 10−6 were estimated. The capacity of HOONO for partition between different phases and for generation of OH· radicals in either of these phases can be of paramount importance for understanding the mechanism of lipid membrane oxidation initiated by peroxynitrous acid.__________Translated from Kinetika i Kataliz, Vol. 46, No. 3, 2005, pp. 370–379.Original Russian Text Copyright © 2005 by Lobachev, Rudakov. 相似文献
54.
V. V. Zamashchikov E. S. Rudakov S. A. Mitchenko 《Reaction Kinetics and Catalysis Letters》1982,21(1-2):141-144
Platinum(II) catalyzes the reduction of alkyl iodides to alkanes according to a mechanism involving oxidative addition of RI to Pt(II), reduction of the product complex RPt(IV) to RPt(II) by iodide ions and protolysis of the latter particle.
(II) , RI PtII, - RPtIV RPtII .相似文献
55.
56.
D. A. Rudakov V. I. Potkin A. N. Ryabtsev I. B. Sivaev 《Journal of Applied Spectroscopy》2006,73(4):616-619
In the 11B NMR spectra of dihalo derivatives of bis(dicarbollyl)cobalt(III), we have identified a correlation between the 11B NMR chemical shifts of substituted boron atoms and boron atoms found in other positions on the carborane skeleton. We have
observed an increased shielding effect for fluorine atoms (compared with other halogens), manifested in an upfield shift of
the 11B NMR signals for antipodal and trans boron atoms. For the fluorine-containing compound Bu4N+ [8,8′-F2-3,3′-Co(1,2-C2B9H10)2]−, we propose the following sequence of electron density transfer: B(8) → {B(6) and B(10)} → B(4, 7).
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 547–549 (cont.), July–August, 2006. 相似文献
57.
V. L. Lobachev Ya. V. Matvienko E. S. Rudakov 《Theoretical and Experimental Chemistry》2009,45(4):239-245
A study was carried out on the rate constant ratio (k
RH/k
EtH) in reactions of alkanes C3H8, n-C4H10, n-C5H12, n-C6H14, i-C4H10, c-C5H10, and c-C6H12 with OH radicals in water at 5-55°C and the relative activation parameters A
RH/A
EtH and E
EtH – E
RH. The values of E
EtH – E
RH in water and the gas phase have opposite signs. The values of k
RH/k
EtH decrease with increasing temperature in the gas phase but increase in water. The behavior of these reactions in water may
be attributed to a solvent cage effect. 相似文献
58.
Mikhaltsevitch VT Rudakov TN Flexman JH Hayes PA Chisholm WP 《Solid state nuclear magnetic resonance》2004,25(1-3):61-63
Experimental results of comparing composite pulses in nitrogen-14 NQR, that are analogous to common 90 degrees RF pulses in powder, are presented. All tested pulses have been taken from publications in journals. Comparative diagrams of the measurement results for induction signals and echo signals are presented. The results of the measurements demonstrate that the best outcomes are achieved when the composite pulse (45)0(95)180(164)0 is used. 相似文献
59.
Rudakov TN Mikhaltsevitch VT Flexman JH 《Solid state nuclear magnetic resonance》2004,25(1-3):112-118
The behaviour of the magnetisation in the spin-1 system with the axial symmetry of the electric field gradient (EFG) tensor was analysed theoretically. The behaviour of the NQR signals in hexamethylenetetramine (C6H12N4) was also studied experimentally using the pulse NQR technique and sensitive equipment. It was shown that the axial symmetry of the EFG in a sample could not be the reason why spin-echo signals were not observed in conventional pulse experiments for the same type of sample. A very short spin-spin relaxation time T2 seems to be the reason of that. The signal-to-noise ratio was sufficient for measuring T2 in C6H12N4, which had not been reported earlier. Experimental results of applying certain pulse sequences to the 14N NQR in a sample are also presented. 相似文献
60.