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2 edition of Reductive dechlorination of chlorophenols by vitamin B found in the catalog.

Reductive dechlorination of chlorophenols by vitamin B

Mark Harrison Smith

Reductive dechlorination of chlorophenols by vitamin B

by Mark Harrison Smith

  • 192 Want to read
  • 33 Currently reading

Published .
Written in English

    Subjects:
  • Vitamin B .,
  • Chlorophenols.

  • Edition Notes

    Statementby Mark H. Smith.
    The Physical Object
    Pagination164 leaves, bound. :
    Number of Pages164
    ID Numbers
    Open LibraryOL15200799M

    Reductive Dechlorination of Chlorophenols by Vitamin B 12 by Mark H. Smith A THESIS submitted to Oregon State For NT.S C".&I P1I!C; IAB El i.1i!! Vitamin B12 catalyzed the reductive dechlorination of PCE and TCE, thus suggesting that vitamin B12 may be useful for dechlorination of polluted environments. – In order to obtain information on the mechanism involved in these processes, the synthesis of chloroethenylcobaloxime has been performed.

    We have hypothesized that hydrogen gas intercalated in a palladium lattice is the powerful reducing agent that reductively dechlorinates chlorinated organic compounds that are adsorbed on the surface of palladized electrodes. We have shown that dechlorination of 4-chlorophenol to phenol occurs rapidly on palladized carbon cloth or pal ladized graphite by: The reductive dechlorination of chlorinated phenols by vitamin B[sub 12], supported by the reductant Ti(III) citrate, was examined. Procedures were developed, including a novel reactor system, for conducting these experiments.

    The bacterial transition-metal coenzymes vitamin B{sub 12} (Co), coenzyme F{sub } (ni), and hematin (Fe) catalyzed the reductive dechlorination of polychlorinated ethylenes and benzenes, whereas the electron-transfer proteins four-iron ferredoxin, two . logenations has led to speculation that vitamin B12 mayserve as anabioticmodelofbiological reductive dechlorination (10). Most investigations of dehalogenation by vitamin B12 are conducted with serum bottles (1, 4, 9, 10) by using modifica-tions (13) of the Hungate technique (5, 6, 12). Because reductive dechlorination of chlorinated alkanes Cited by:


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Reductive dechlorination of chlorophenols by vitamin B by Mark Harrison Smith Download PDF EPUB FB2

Concluded that any involvement of vitamin B 12 in biological reductive dechlorination of chlorinated phenols requires the intimate participation of apoenzymes to direct the regiospecificity toward the 2 and 6 chlorines on the ring.

Reductive dechlorination of chlorophenols by vitamin BAuthor: Mark Harrison Smith. Vitamin B 12, reduced by titanium (III) citrate to vitamin B 12s, catalyzes the reductive dechlorination of chlorophenols.

Reductive dechlorination of pentachlorophenol and of all tetrachlorophenol and trichlorophenol isomers was by: Reductive dechlorination ofCPshas been observed for unacclimated and acclimated anaerobic sewage sludges, sediments, soils amended with sewage sludge, and aquifers (Fig.

The reductive dechlorination process is of environmental importance because the less-chlorinated metabolic products are generally less toxic and * Corresponding by: Microbial reductive dechlorination reactions play an important role in determining the environmental fate of polychlorinated biphenyls (PCBs), especially for PCB congeners with more than four chlorines.

Powerful chemical catalysts such as vitamin B12s provide an effective tool for the study of reductive dechlorination reactions. The reductive dechlorination of PCBs by titanium(III) citrate Cited by: Smith MH, Woods SL.

Regiospecificity of chlorophenol reductive dechlorination by vitamin b(12s). Appl Environ Microbiol. Nov; 60 (11)– [PMC free article] Smith MH, Woods SL. Regiospecificity of chlorophenol reductive dechlorination by vitamin b(12s). Appl Environ Microbiol. Nov; 60 (11)– [PMC free article].

Reaction of various chlorophenols with vitamin B(12) favored reductive dechlorination at positions adjacent to another chlorinated carbon, but chlorines ortho to the hydroxyl group of a phenol. Reductive dechlorination of chlorophenols by vitamin B(12) reduced with Ti(III) citrate was monitored in all three reactor types.

Sealed ampoules maintained reducing conditions for. Vitamin B12 catalyzed the reductive dechlorination of PCE and TCE, thus suggesting that vitamin B12 may be useful for dechlorination of polluted environments.

– In order to obtain information on the mechanism involved in these processes, the synthesis of chloroethenylcobaloxime. Reductive dechlorination of polychlorinated dibenzo-p-dioxins (PCDDs) involves reactions linking 76 congeners with highly variable toxicities, so it is challenging to assess the overall effect.

Vitamin B 12 catalyzes the reductive dechlorination of several ubiquitous pollutants including the conversion of trichloroethylene (TCE) to ∼95% cis-1,2-dichloroethylene (DCE) and small amounts of trans-DCE and 1, origins of this unexpected selectivity were investigated using density functional and coupled-cluster theory.

At all levels of theory considered, the initially formed Cited by: Reductive dechlorination of 2‐chlorophenol by Anaeromyxobacter dehalogenans with an electrode serving as the electron donor Sarah M.

Strycharz. Corresponding Author. Electrodes poised at potentials low enough to serve as an electron donor for microbial respiration, but high enough to avoid the production of hydrogen, have been proposed as.

Reductive dechlorination of a polychlorinated biphenyl congener and hexachlorobenzene by vitamin B (). Reductive dechlorination of chlorophenols by a pentachlorophenol-acclimated methanogenic consortium. Reductive dechlorination of dichlorophenols by nonadapted and adapted microbial communities in pond sediments.

Smith MH, Woods SL. Regiospecificity of chlorophenol reductive dechlorination by vitamin b(12s). Appl Environ Microbiol. Nov; 60 (11)– [PMC free article] Smith MH, Woods SL. Regiospecificity of chlorophenol reductive dechlorination by vitamin b.

A remarkable reductive dechlorination of PCE (±h−1) was observed in nZVI suspension (g/24mL) with mM vitamin B12 in 6h, while no significant reductive dechlorination of Author: Mark H Smith.

Reductive dechlorination of CPs by vitamin B,2s. Vitamin B12scompletelytransformed PCPto amixtureof2,3,4,6-TeCP and 2,3,5,6-TeCP, which was subsequently transformed to 2,3,6-TCP and 2,4,6-TCP (Fig.

TheTCPsappeared in the molar ratio of 56% 2,3,6-TCP 44% 2,4,6-TCP. Eighty-eight percent of the PCPwas degraded within 24 h, and 96%was by: Reaction of various chlorophenols with vitamin B(12) favored reductive dechlorination at positions adjacent to another chlorinated carbon, but chlorines ortho to the hydroxyl group of a phenol were particularly resistant to reductive dechlorination, even if they were also ortho to a by: We demonstrated that the addition of vitamin B 12 can significantly enhance the reductive dechlorination of tetrachloroethene (PCE) by nano-sized zero valent iron (nZVI).

A remarkable reductive dechlorination of PCE ( ± h −1) was observed in nZVI suspension ( g/24 mL) with mM vitamin B 12 in 6 h, while no significant reductive dechlorination of PCE was observed Cited by: The reductive dechlorination of chlorophenols have been investigated through adding co-substrates or electron mediators in constructed bioelectrochemical systems (Zhang et al.,; Liu et al., ; Wang et al., ).

However, the electrochemical and microbial mechanisms of the electro-stimulated bio-dechlorination require further by: The lower chamber contained the oxygen-sensitive reaction mixture. The upper chamber, sealed with a septum and screw cap, was purged with purified nitrogen or argon introduced and vented through fused silica capillaries.

Reductive dechlorination of chlorophenols by vitamin B 12 reduced with Ti(III) citrate was monitored in all three reactor types.

Sealed ampoules maintained reducing conditions for Cited by:. Reductive dechlorination of chlorophenols by vitamin B(12) reduced with Ti(III) citrate was monitored in all three reactor types. Sealed ampoules maintained reducing conditions for up to 12 months. The two-chambered reactor maintained reducing conditions longer than the serum vials when frequent samples were by: Regiospecificity of chlorophenol reductive dechlorination by vitamin b(12s).

Smith MH, Woods SL. Appl Environ Microbiol, 60(11), 01 Nov Cited by: 7 articles | PMID: | PMCID: PMC Free to read.Review Reductive dechlorination in the energy metabolism of anaerobic bacteria Christof Holliger a, Gert Wohlfarth b, Gabriele Diekert b;* a Swiss Federal Institute for Environmental Science and Technology (EAWAG), Limnological Research Center, CH Kastanienbaum, Switzerland b University of Stuttgart, Institute for Microbiology, Allmandr D Stuttgart, GermanyFile Size: KB.