Recombination of 1,1-dimethylpropyl peroxy radicals in polar solvents

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• 作者：T. G. Denisova ; V. F. Shuvalov
• 关键词：1 ; 1 ; dimethylpropyl peroxy radical ; rate constant ; electron paramagnetic resonance ; stopped ; flow method ; nonspecific solvation ; Kirkwood function
• 刊名：Kinetics and Catalysis
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：57
• 期：1
• 页码：22-25
• 全文大小：279 KB
• 参考文献：1.Denisov, E.T. and Afanas’ev, I.B., Oxidation and Antioxidants in Organic Chemistry and Biology, Boca Raton, Fla.: CRC, Taylor and Francis Group, 2005.CrossRef
  2.Mill, T. and Hendry, D.G., in Comprehensive Chemical Kinetics, Bamford, C.H. and Tipper, C.F.., Eds., Amsterdam: Elsevier, 1980, vol. 16, p. 1.CrossRef
  3.Denisov, E.T., Denisova, T.G., Trepalin, S.V., and Drozdova, T.I., Data Base of Oxidation and Antioxidants in Organic Chemistry, Boca Raton, Fla.: CRC, Taylor and Francis Group, 2005.CrossRef
  4.Emanuel’, N.M., Zaikov, G.E., and Maizus, Z.K., Rol’ sredy v radikal’no-tsepnykh reaktsiyakh okisleniya organicheskikh soedinenii (Role of the Medium in FreeRadical Chain Oxidation of Organic Compounds), Moscow: Nauka, 1973.
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  8. Spravochnik khimika (Chemist’s Handbook), vol. 2: Osnovnye svoistva neorganicheskikh i organicheskikh soedinenii (Main Properties of Inorganic and Organic Compounds., Nikol’skii, B.P., Ed., Leningrad: Goskhimizdat, 1963, 2nd ed.
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  11.Denisov, E.T., Sarkisov, O.M., and Likhtenshtein, G.I., Khimicheskaya kinetika (Chemical Kinetics), Moscow: Khimiya, 2000.
  
• 作者单位：T. G. Denisova (1)
  V. F. Shuvalov (1)
  
  1. Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432, Russia
  
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Catalysis
  Physical Chemistry
  Russian Library of Science
  
• 出版者：MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC.
• ISSN：1608-3210

文摘

The kinetics of 1,1-dimethylpropyl peroxy radicals recombination in polar solvents—water, methanol, and their mixtures—was studied by EPR spectroscopy in combination with the stopped-flow method, and the rate constants of this reaction were determined. Peroxyl radicals were generated by mixing solutions of Ce4+ sulfate and 1,1-dimethylpropyl hydroperoxide. The observed EPR signal of the peroxyl radical is a singlet with a g-factor of 2.015 ± 0.001, and a line width of ΔH = (1.36 ± 0.02) × 10−3 T for methanol and ΔH = (9.7 ± 0.2) × 10−4 T for water. The measured rate constants of (CH₃)₂C(O₂ ·)CH₂CH₃ radical recombination at 298 K are 2k _t = (3.9 ± 0.4) × 104 L mol−1 s−1 for water and 2k _t = (5.2 ± 0.5) × 103 L mol−1 s−1 for methanol. A linear relationship between ln(2k _t ) and the Kirkwood function (ε−1)/(2ε + 1), where e is the dielectric constant of the medium, has been established, indicating an important role of nonspecific solvation in the recombination of tertiary peroxyl radicals.