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1.
S. V. Semikolenov K. A. Dubkov E. V. Starokon' D. E. Babushkin G. I. Panov 《Russian Chemical Bulletin》2005,54(4):948-956
The kinetics and mechanism of noncatalytic liquid-phase oxidation of but-1-ene and but-2-ene with nitrous oxide in a benzene
solution in the temperature range from 180 to 240°C were studied. Oxidation proceeds via the 1,3-dipolar cycloaddition mechanism to form carbonyl compounds. Both of these reactions occur with close rates and activation
energies and have the first orders with respect to the alkene and N2O. A considerable fraction (39%) of but-1-ene involved in oxidation undergoes cleavage at the double bond yielding propanal
and an equivalent amount of methylene, the latter producing ethylcyclopropane and cycloheptatriene. The oxidation of but-2-ene
proceeds with a minimum bond cleavage and affords methyl ethyl ketone with 84% selectivity. Regularities of the oxidation
of terminal and internal alkenes C2—C8 with nitrous oxide were analyzed using the previously published data.
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Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 925–933, April, 2005. 相似文献
2.
E. V. Starokon’ K. S. Shubnikov K. A. Dubkov A. S. Kharitonov G. I. Panov 《Kinetics and Catalysis》2007,48(3):376-380
It is demonstrated by the example of cyclopentene that the noncatalytic oxidation of alkenes with nitrous oxide to carbonyl compounds (carboxidation), which is known to occur in the liquid phase at 150–250°C, can also take place in the gas phase at higher temperatures (300–475°C). Like liquid-phase carboxidation, the gas-phase reaction likely proceeds via a dipolar 1,3-addition mechanism. However, 4-pentenal is formed along with cyclopentanone in the gas phase. The 4-pentenal selectivity increases from 2.5 to 23% as the reaction temperature is raised. High-temperature cyclopentene carboxidation can be carried out in a paraffin melt (bp ~ 400°C). Filling the reactor with paraffin accelerates the reaction and reduces its activation energy. 相似文献
3.
Spike train regularity of the noisy neural auditory system model under the influence of two sinusoidal signals with different frequencies is investigated. For the increasing ratio m/n of the input signal frequencies (m, n are natural numbers) the linear growth of the regularity is found at the fixed difference (m - n). It is shown that the spike train regularity in the model is high for harmonious chords of input tones and low for dissonant ones. 相似文献
4.
Radiophysics and Quantum Electronics - 相似文献
5.
B. Spagnolo A. Dubkov 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):299-303
The one-dimensional overdamped Brownian motion in a symmetric
periodic potential modulated by external time-reversible noise is
analyzed. The calculation of the effective diffusion coefficient
is reduced to the mean first passage time problem. We derive
general equations to calculate the effective diffusion coefficient
of Brownian particles moving in arbitrary supersymmetric potential
modulated by: (i) an external white Gaussian noise and (ii) a
Markovian dichotomous noise. For both cases the exact expressions
for the effective diffusion coefficient are derived. We obtain
acceleration of diffusion in comparison with the free diffusion
case for fast fluctuating potentials with arbitrary profile and
for sawtooth potential in case (ii). In this case the parameter
region where this effect can be observed is given. We obtain also
a finite net diffusion in the absence of thermal noise. For
rectangular potential the diffusion slows down, for all parameters
of noise and of potential, in comparison with the case when
particles diffuse freely. 相似文献
6.
Based on the previously introduced integral criterion and a new approach to estimating the time characteristics of diffusion, the relaxation time of impurity concentration in a medium with a slightly nonuniform diffusion coefficient is determined. The diffusion coefficient profile that cuts the relaxation time is found. 相似文献
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9.
Dubkov K. A. Piryutko L. V. Kharitonov A. S. 《Russian Journal of Applied Chemistry》2019,92(7):924-932
Russian Journal of Applied Chemistry - The possibility of reaching the equilibrium in structural isomerization of 1-butene on acid-base catalysts in the temperature interval 20–100°C was... 相似文献
10.