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S. I. Kuzina A. P. Kharitonov Yu. L. Moskvin A. I. Mikhailov 《Russian Chemical Bulletin》1996,45(7):1623-1627
The formation of free radicals in the process of direct fluorination of natural and synthetic polymers at temperatures close to 77 K was studied by ESR. The maximum concentrations of radicals, (1017–5·1018 spin g–1) and their complete oxidation were observed in the temperature interval from 77 to 250 K at a fluorine pressure of 30 Torr. The initiation of chain halogenation, which consists of homolytic breaking of chemical bonds to yield free-radical intermediates. was examined in the framework of the multi-center synchronous transitions model. 相似文献
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《Journal of fluorine chemistry》1987,35(3):557-569
The electrochemical fluorination of acetyl fluoride in anhydrous hydrogen fluoride to produce trifluoroacetyl fluoride was investigated in a microprocessor-aided modified Simons' reactor. The product was recovered in acetic acid as trifluoroacetic acid. The experiments were carried out at a controlled anodic potential using a Cu/CuF2 reference electrode. Product yields of 36 - 45%, current efficiencies of 30 to 50% and energy efficiencies of 11 – 23% were obtained.Experimental results of this investigation are presented and discussed. 相似文献
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Matalin V. A. Kaurova G. I. Berenblit V. V. Lebedev N. V. 《Russian Journal of Applied Chemistry》2011,84(6):1056-1063
Products of electrochemical fluorination of tripropylamine and triallylamine were studied by gas chromatography-mass spectrometry
and high-resolution 19F NMR spectroscopy. The use of these methods allowed identification of the structures and isomeric composition of components
of the electrolysis products. 相似文献
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Selective fluorination of adamantanes was achieved by the electrochemical fluorination method, using Et 3N-5HF as electrolyte and a fluorine source. Mono-, di-, tri-, and tetrafluoroadamantanes were selectively prepared from adamantanes by controlling the oxidation potential, and the fluorine atoms were introduced selectively at the tertiary carbons. Adamantanes that have functional groups such as ester, cyano, and acetoxymethyl were also fluorinated selectively. 相似文献
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Recent studies on electrochemical partial fluorination in ionic liquid fluoride salts are reviewed. At first, historical background and some problems of electrochemical fluorination in organic solvents are briefly mentioned. Solvent-free electrochemical fluorinations in ionic liquids are explained as follows. Ultrasonication was found to improve both the yield and current efficiency for electrochemical fluorination of α-phenylthioacetate, which is mainly attributable to marked mass transport promotion of the substrate and the suppression of anode passivation. Highly regioselective and efficient fluorination of cyclic ethers, lactones, and cyclic carbonate was achieved in Et4NF·4HF and Et3N·5HF. Selective fluorination of hardly oxidizable phthalide was realized using a combination of imidazolium and fluoride ionic liquids. The unique effect of imidazolium ionic liquids on electrochemical fluorodesulfurization of 3-phenylthiophthalide was explained. Reuse of ionic liquids for electrochemical fluorination is also possible. 相似文献
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R. Gavars L. Baumane Ya. Stradyn B. Chekavichus G. Duburs 《Chemistry of Heterocyclic Compounds》1998,34(8):950-956
The polarographic properties (potentials, number of electrons, reversibility) of the electrochemical reduction of 3,5-diethoxycarbonyl-3-(p-nitrobenzoyl)-6-(p-nitrophenyl)-1,2,3,4-tetrahydropyridine and its derivatives in dimethylformamide have been determined. In the course of the electrochemical generation, ESR spectra of primary radical anions of p-nitrobenzoyl structure were obtained along with ESR spectra of nitrophenyl-p-substituted free radicals formed as a result of further reduction.Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1103–1110, August, 1998. 相似文献
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Generally speaking, measurement of hydroxylated radical products of salicylic acid requires a fussy separation process. In this study, we describe a simple method to electrochemically detect hydroxyl radicals (*OH) using 4-hydroxybenzoic acid (4-HBA) as the *OH trap. The *OH is generated by the Fenton reaction from iron (II) sulfate and hydrogen peroxide in a phosphate buffer solution. Experimental results show that our method can detect the OH with high sensitivity without any separation process. The differential pulse voltammetric responses show a linear dependence on the concentration of *OH in a range of 2.0x10(-6) and 1.0x10(-3)M with a determination limit down to 5.0x10(-7)M. As a demonstration, the kinetics of the Fenton reaction was mapped by measuring the reaction product of hydroxyl radical trapped by 4-HBA. The result is in good agreement with that reported previously. All the results show that the present approach could provide a simple, inexpensive and promising method for biomedicine and iatrology. 相似文献
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A.I. Prokofev T.I. Prokofeva I.S. Belostotskaya N.N. Bubnov S.P. Solodovnikov V.V. Ershov M.I. Kabachnik 《Tetrahedron》1979,35(20):2471-2482
Silicon-containing free radicals with 3,6-di-t-butylpyrocatechinic ligands have been investigated by ESR method. Intramolecular migrations of free valence and bond was found for these systems. It was considered in terms of intramolecular radical substitution. 相似文献
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A modification to the standard method of electrochemical fluorination is described which embodies a forced flow of electrolyte through the electrode pack. A preliminary study of flow characteristics through an electrode pack was carried out.Good yields of perfluorooctanoyl fluoride and associated perfluorinated products are reported. The nature of the anode surface was studied before and after fluorination by scanning electron microscopy. 相似文献
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This article provides an outline of recent studies on selective electrochemical fluorination in ionic liquid fluoride salts toward green sustainable chemistry. First, a brief historical background of electrochemical fluorination in organic solvents is provided, and some particular problems and unique solvent effects associated with this technique are briefly mentioned. Second, recent progress in selective fluorination and fluorodesulfurization of organic molecules and macromolecules in ionic liquids using direct and indirect electrolysis with recyclable mediators is reviewed. 相似文献
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