Direct reduction of halogenated biphenyls at mercury electrodes

Rusling, James F.; Arena, James V.

doi:10.1016/0368-1874(85)85768-3

Cited by 15 publications

(7 citation statements)

References 20 publications

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“…Clearly, the difference between PCB and brominated biphenyl dehalogenation is not simply a matter of reduction potential. The reduction potentials of 4-4-CB and 25-25-CB are higher than that of 4-BB (20); yet these PCBs are not dehalogenation substrates in Woods Pond (Table 1 and references 3 and 24). If the same microorganisms do indeed dehalogenate both brominated and chlorinated biphenyls, it appears that the dehalogenases show a relaxed specificity for bromophenyl groups.…”

Section: Discussionmentioning

confidence: 99%

“…The aryl-bromine bond is weaker than the aryl-chlorine bond (dissociation energies for the C 6 H 5 -Br and C 6 H 5 -Cl bonds are 80 and 95 kcal/mol, respectively (see Table 5, p. F-243, in reference 25). In addition, chemical dehalogenations carried out by various reaction mechanisms have consistently shown that aryl bromines are more easily removed than aryl chlorines (8,13,20).…”

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confidence: 99%

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Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

Bedard¹,

Dort²

1998

Appl Environ Microbiol

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We sought to determine whether microorganisms from the polychlorinated biphenyl (PCB)-contaminated sediment in Woods Pond (Lenox, Mass.) could dehalogenate brominated biphenyls. The PCB dechlorination specificities for the microorganisms in this sediment have been well characterized. This allowed us to compare the dehalogenation specificities for brominated biphenyls and chlorinated biphenyls within a single sediment. Anaerobic sediment microcosms were incubated separately at 25°C with 16 different mono- to tetrabrominated biphenyls (350 μM) and disodium malate (10 mM). Samples were extracted and analyzed by gas chromatography with an electron capture detector and a mass spectrometer detector at various times for up to 54 weeks. All of the tested brominated biphenyls were dehalogenated. For most congeners, including 2,6-dibromobiphenyl (26-BB) and 24-25-BB, the dehalogenation began within 1 to 2 weeks. However, for 246-BB and 2-2-BB, debromination was first observed at 7 and 14 weeks, respectively. Most intermediate products did not persist, but when 2-2-BB was produced as a dehalogenation product, it persisted for at least 15 weeks before it was dehalogenated to 2-BB and then to biphenyl. The dehalogenation specificities for brominated and chlorinated biphenyls were similar: meta andpara substituents were generally removed first, andortho substituents were more recalcitrant. However, the brominated biphenyls were better dehalogenation substrates than the chlorinated biphenyls. All of the tested bromobiphenyls, including those with ortho and unflankedmeta and para substituents, were ultimately dehalogenated to biphenyl, whereas their chlorinated counterparts either were not dehalogenation substrates or were only partially dehalogenated. Our data suggest that PCB-dechlorinating microorganisms may be able to dehalogenate brominated biphenyls and may exhibit a relaxed specificity for these substrates.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

Bedard¹,

Dort²

1998

Appl Environ Microbiol

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“…The reactivity of polyhalogenated biphenyls in reductive processes can be predicted from formal potentials (£"') of the first one-electron transfer. These fundamental parameters have been estimated so far only in organic media such as DMF (7,13). Direct measurement of formal potentials for polyhalogenated biphenyls is difficult because of a chemical cleavage following the initial electron transfer.…”

mentioning

confidence: 99%

Formal Reduction Potentials and Redox Chemistry of Polyhalogenated Biphenyls in a Bicontinuous Microemulsion

Huang¹,

Rusling²

1995

Environ. Sci. Technol.

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“…An investigation of the electrochemistry of the entire family of chlorinated benzenes has been reported [65], and the dechlorinations of 1,2,3,5-tetrachlorobenzene [57] and of 2,4-dichlorophenoxyacetic acid (a herbicide) have been accomplished [66]. Several papers dealing with the reduction of chlorinated biphenyls have appeared [67][68][69].…”

Section: Aryl Halidesmentioning

confidence: 99%

Oxidation and Reduction of Halogen‐containing Compounds

Peters

2004

Encyclopedia of Electrochemistry

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The sections in this article are Introduction Anodic Processes Halogenated Alkanes Alicyclic Halides Aryl Halides Cathodic Processes Halogenated Alkanes Halogenated Alkenes and Alkynes Benzyl Halides Alicyclic Halides Aryl Halides Acyl and Phenacyl Halides Aliphatic α‐Halocarbonyl Compounds Halogenated Heterocyclic Compounds Catalytic Reduction of Carbon–Halogen Bonds

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Direct reduction of halogenated biphenyls at mercury electrodes

Cited by 15 publications

References 20 publications

Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

Formal Reduction Potentials and Redox Chemistry of Polyhalogenated Biphenyls in a Bicontinuous Microemulsion

Oxidation and Reduction of Halogen‐containing Compounds

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