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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.
Dubkov K. A. Starokon' E. V. Paukshtis E. A. Volodin A. M. Panov G. I. 《Kinetics and Catalysis》2004,45(2):202-208
The mechanism of a low-temperature reaction of hydrogen with the radical anion surface oxygen species (-oxygen, ) formed by decomposing N2O over FeZSM-5 zeolite was studied using kinetic and isotope techniques. It was found that the reaction is of first order with respect to hydrogen and the rate of the reaction is proportional to the concentration of . The activation energy of the reaction, which was measured for 2 or D2 over a temperature range from +20 to –;;100°, is equal to 3.2 or 5.3 kcal/mol, respectively. The reaction occurs with a considerable kinetic isotope effect (k
/k
D), which varies over the range of 3.4–;;41 depending on the temperature. This fact indicates that the rate-limiting step of the reaction includes the dissociation of the hydrogen molecule. The temperature dependence of the isotope effect gave a value of 2.1 kcal/mol, which is close to the difference between the zero bond energies in the molecules of 2 and D2; this fact suggests that a tunnel effect does not significantly contribute to the reaction. The dissociative mechanism is consistent with data obtained by in situ IR spectroscopy. The interaction of hydrogen with -oxygen is accompanied by the formation of new hydroxyl groups (absorption bands at 3635 and 3674 cm–;;1) at the surface of the zeolite. The identification of these groups was supported by an isotope shift either on the replacement of 2 by D2 or on the replacement of 16 by 18. The stoichiometric ratio 2 : is consistent with the previously drawn conclusion on the paired arrangement of -sites. 相似文献
3.
Vaganova T. A. Starokon' E. V. Shteingarts V. D. 《Russian Journal of Organic Chemistry》2003,39(5):680-685
Study of oxidation, protonation, and alkylation of the products obtained by one- and two-electron reduction of p-tolunitrile with sodium in liquid ammonia showed that these products are, respectively, p-tolunitrile radical anion and 1-cyano-4-methyl-2,5-cyclohexadienyl anion. The latter is formed by protonation of p-tolunitrile dianion with ammonia. The two-electron reduction involves protonation of p-tolunitrile dianion with initial p-tolunitrile, which gives rise to 4-cyanobenzyl anion. The yield of the latter depends on the order of mixing of the reactants. The anionic reduction products react with butyl bromide to afford products corresponding to ipso alkylation with respect to the cyano group, 4-butyltoluene and 3-butyl-3-cyano-6-methyl-1,4-cyclohexadiene, as well as the alkylation product at the benzylic position, 4-pentylbenzonitrile. The formation of 4-butyltoluene indicates the possibility for selective synthesis of p-alkyltoluenes by reductive alkylation of p-tolunitrile. 相似文献
4.
T. A. Vaganova E. V. Starokon' V. D. Shteingarts 《Russian Journal of Organic Chemistry》2002,38(6):823-829
From results of oxidation, protonation, and alkylation of the products arising in one- or two- electron reduction of m-tolunitrile with sodium in liquid ammonia followed a conclusion that these products are respectively anion-radical of the compound and 3-methyl-1-cyano-2,5-cyclohexadienyl anion. The reaction of both reduction products with alkyl halides gives rise to compounds of ipso-alkylation with respect to cyano group: the corresponding alkyltoluenes and 1-alkyl-3-methyl-1-cyclohexadienes. The ratio of these products depends on the structure of alkyl halide. The possibility to prepare selectively m-alkyltoluenes by reaction of the product of two-electron reduction of m-tolunitrile with alkyl halides was demonstrated. 相似文献
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