Indirect anodic oxidation in strongly acidic media
Indirect anodic oxidation in strongly acidic media
The indirect electrochemical oxidation of organic compounds in two strongly acidic solvents, FS03H and CH 3S03H, is considered, and in both cases the intermediate redox reagent is a peroxide formed by the oxidation of FSO3 and CH3S03 respectively.A simple and safe preparation of bismethylsulphonyl peroxide, (CH3S03)2,(yield 75%), has been developed by constant current oxidation of a solution of sodium methanesulphonate in anhydrous methanesulphonic acid. The reactions of bismethylsulphonyl peroxide with benzene, naphthalene and other aromatic hydrocarbons are reported.The constant current oxidation of FS03 in FSO3H at a platinum electrode was shown to give peroxydisulphuryl difluoride, (F503)2, in good yield (90%). The reactions of this peroxide with carboxylic acids C3 - C8 both in situ in the anolyte during electrolysis and exterior to the cell are shown to be rapid and smooth. Oxidation occurs at a site remote from the carboxyl group and after work-up lactones are isolated (organic yields 20-65%). To allow the study of the kinetics of the peroxide with the organic substrates it was necessary to develop a new double pulse method. During the first pulse, T s, a constant current, IA, is used to generate the reactive intermediate (in this case the peroxide) and during the second pulse at constant potential, the intermediate remaining in solution is monitored. The theory is developed and it is demonstrated that analysis of the I-t transient on the second pulse allows both the reaction order to be distinguished and the rate constant to be measured. The method, which has particular advantages when the reactive intermediate results from oxidation or reduction of the base electrolyte or solvent, is tested using some bromination reactions. Studies of the reactions of (F503)'2 indicate that initial attack, of the peroxide on the substrate is by a hydrogen abstraction mechanism.
University of Southampton
1977
Myall, Christopher John
(1977)
Indirect anodic oxidation in strongly acidic media.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The indirect electrochemical oxidation of organic compounds in two strongly acidic solvents, FS03H and CH 3S03H, is considered, and in both cases the intermediate redox reagent is a peroxide formed by the oxidation of FSO3 and CH3S03 respectively.A simple and safe preparation of bismethylsulphonyl peroxide, (CH3S03)2,(yield 75%), has been developed by constant current oxidation of a solution of sodium methanesulphonate in anhydrous methanesulphonic acid. The reactions of bismethylsulphonyl peroxide with benzene, naphthalene and other aromatic hydrocarbons are reported.The constant current oxidation of FS03 in FSO3H at a platinum electrode was shown to give peroxydisulphuryl difluoride, (F503)2, in good yield (90%). The reactions of this peroxide with carboxylic acids C3 - C8 both in situ in the anolyte during electrolysis and exterior to the cell are shown to be rapid and smooth. Oxidation occurs at a site remote from the carboxyl group and after work-up lactones are isolated (organic yields 20-65%). To allow the study of the kinetics of the peroxide with the organic substrates it was necessary to develop a new double pulse method. During the first pulse, T s, a constant current, IA, is used to generate the reactive intermediate (in this case the peroxide) and during the second pulse at constant potential, the intermediate remaining in solution is monitored. The theory is developed and it is demonstrated that analysis of the I-t transient on the second pulse allows both the reaction order to be distinguished and the rate constant to be measured. The method, which has particular advantages when the reactive intermediate results from oxidation or reduction of the base electrolyte or solvent, is tested using some bromination reactions. Studies of the reactions of (F503)'2 indicate that initial attack, of the peroxide on the substrate is by a hydrogen abstraction mechanism.
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Published date: 1977
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Local EPrints ID: 462687
URI: http://eprints.soton.ac.uk/id/eprint/462687
PURE UUID: 544403d8-7de5-4ebf-92c0-6942e94e2aa5
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Date deposited: 04 Jul 2022 19:41
Last modified: 04 Jul 2022 19:41
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Author:
Christopher John Myall
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