Application of the solid polymer electrolyte method to organic electrochemistry; 17: Indirect electrochemical debromination using viologens as microscopic phase-transfer mediators

Journal Article · Sat Oct 01 00:00:00 EDT 1994 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2059122· OSTI ID:6992852

Inaba, Minoru; Ogumi, Zempachi; Takehara, Zenichiro ^[1]

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1. Kyoto Univ. (Japan). Division of Energy and Hydrocarbon Chemistry

Solid polymer electrolyte composite electrodes have been extensively studied for use in water electrolyzers, brine electrolyzers, and fuel cells. Solid polymer electrolyte (SPE[reg sign]) composite electrodes using a perfluorinated ion-exchange membrane (Nafion[reg sign]), which is known to be microscopically separated into hydrophilic and hydrophobic domains, were prepared. Various N,N[prime]-dialkyl-4-4[prime]-bipyridinium salts (viologens) were incorporated in the SPE composite electrodes as phase transfer mediators. Electrochemical debromination of meso-1,2-dibromo-1,2-diphenylethane was carried out on the SPE composite electrodes. The results were compared with those obtained in an emulsion system consisting of water and dichloromethane. Of the viologen compounds tested, propyl viologen was the most effective mediator for the SPE composite electrode, while octyl viologen dibromide was the most effective mediator in the emulsion system. The active species for the debromination in the emulsion system was shown to be a doubly reduced neutral form of viologen that was generated by the disproportionation of cation radicals. The disproportionation constant, K[sub d], of octyl viologen cation radical in a two-phase system consisting of water and dichloromethane was estimated to be 809. The reaction mechanism on the SPE composite electrode was discussed, and it was considered that the active species was generated by disproportionation at the microscopically heterogeneous interface between the hydrophilic and hydrophobic domains of the Nafion.

• OSTI ID: 6992852
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 141:10; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
AZINES
BIPYRIDINES
BROMINATED ALIPHATIC HYDROCARBONS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
DEHALOGENATION
ELECTROLYSIS
ELECTROLYTES
HALOGENATED ALIPHATIC HYDROCARBONS
HETEROCYCLIC COMPOUNDS
LYSIS
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
SOLID ELECTROLYTES
SYNTHESIS