Photodechlorination of octachlorodibenzo-p-dioxin and octachlorodibenzofuran in alkane solvents in the absence and presence of triethylamine

Konstantinov, Alexandre D.; Bunce, Nigel J.

doi:10.1016/1010-6030(95)04174-5

Cited by 20 publications

(16 citation statements)

References 30 publications

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“…The photolysis rate constants and half-lives ( t 1/2 ) of 18 irradiated PFDDs are listed in Table . As anticipated, the congeners with higher fluorination have lower rate constants in general, similar to the previous study on PCDDs photolysis …”

Section: Resultssupporting

confidence: 89%

“…As anticipated, the congeners with higher fluorination have lower rate constants in general, similar to the previous study on PCDDs photolysis. 34 Compared with PCDDs, the photolysis half-lives of PFDD isomers were different. Taking for example 2,3,7,8-TeFDD, its photodegradation half-life (t 1/2 ) was 0.84 h, and the corresponding t 1/2 value of 2,3,7,8-TeCDD was 7.7 h in the alkane/alcohol mixture solvent.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…Based on the detected 2,3,4,5-tetrafluorocatechols and the mode of C−O bond cleavage of OFPP, we can propose that 1,2,3,4tetrafluorobenzene (P5) is produced. Based on the above analysis and the mechanisms for the photolysis of DD, 44 OCDD, 34 and 2,3,7,8-TeCDD, 45 a proposed mechanism for OFDD photolysis in n-hexane is presented in Figure 4. We propose that C−O bond homolysis of OFDD is the main route and leads to the formation of a diradical as shown in Figure 4.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…Photodegradation is an important way to eliminate persistent organic pollutants (POPs). − Most photoreactions of POPs are conducted in organic solvents due to their very low water solubility. Moreover, it was found that PCDDs in various organic solvents can be degraded substantially. − In contrast, little is known about the photodegradation of PFDDs in organic solvents. Therefore, the photolysis kinetics of some PFDDs in organic solvents was investigated in this work.…”

Section: Introductionmentioning

confidence: 99%

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Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies

Zeng

Feng

et al. 2016

Environ. Sci. Technol.

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Eighteen polyfluorinated dibenzo-p-dioxins (PFDDs) were synthesized by pyrolysis of fluorophenols. Using a 500 W Xe lamp as the light source, the PFDDs photodegradation kinetics in n-hexane were investigated. The photolysis reactions obeyed the pseudo-first-order rate equation, and higher fluorinated PFDDs tended to photolyze more slowly. Theoretically calculated parameters reflecting the molecular structural properties were used to develop a new model of PFDDs photolysis rates. The results indicated that the substitution pattern for fluorine atoms and the C-O bond length were major factors in the photolysis of PFDDs. We selected octafluorinated dibenzo-p-dioxin (OFDD) as a representative PFDDs to explore the influence of solvent on the photolysis rate of PFDDs, and the results indicated that neither the polarity nor donor hydrogen of organic solvents are independent influencing factors. Mechanistic pathways for the photolysis of OFDD in n-hexane were first studied. The results indicated that photodegradation of OFDD produces octafluorinated dihydroxybiphenyls, octafluorinated phenoxyphenols, and fluorinated phenols. The major pathway for photodegradation of OFDD was C-O bond cleavage. Defluorination reactions did not occur during the photolysis process.

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Section: Resultssupporting

confidence: 89%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies

Zeng

Feng

et al. 2016

Environ. Sci. Technol.

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“…Previous work with 18 suggests that both states are reactive in the photodechlorination reactions, but no investigations of aryl-ether cleavage were performed. 19 Because of the increase in spin-orbit coupling, all chlorinated dibenzo [1,4]dioxins are expected to have shorter singlet and triplet state lifetimes than the parent system.…”

Section: Photoproduct Studiesmentioning

confidence: 99%

Photochemical rearrangement of dibenzo[1,4]dioxins proceeds through reactive spirocyclohexadienone and biphenylquinone intermediates

Rayne

Sasaki

Wan

2005

Photochem Photobiol Sci

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Photochemical studies on a range of model dibenzo[1,4]dioxins were performed in aqueous and organic solutions. The compounds were found to undergo a photochemically initiated aryl-ether bond homolysis that yields reactive 2-spiro-6'-cyclohexa-2',4'-dien-1'-one and subsequent 2,2'-biphenylquinone intermediates. Under steady-state irradiation, the 2,2'-biphenylquinones were observed to participate in excited state hydrogen abstraction from the organic solvent to give the corresponding 2,2'-dihydroxybiphenyls. In the absence of continued irradiation, 2,2'-biphenylquinones with electron donating substituents thermally rearrange to the corresponding oxepino[2,3-b]benzofurans, whereas the unsubstituted 2,2'-biphenylquinone and its derivatives with electron withdrawing groups thermally rearrange to the corresponding 1-hydroxydibenzofurans.

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Dechlorination/hydrogenation and destruction reactions of PCDDs in OCDD-added fly ash heated under vacuum

Misaka

Abe²,

Takeuchi

et al. 2006

Chemosphere

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Photodechlorination of octachlorodibenzo-p-dioxin and octachlorodibenzofuran in alkane solvents in the absence and presence of triethylamine

Cited by 20 publications

References 30 publications

Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies

Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies

Photochemical rearrangement of dibenzo[1,4]dioxins proceeds through reactive spirocyclohexadienone and biphenylquinone intermediates

Dechlorination/hydrogenation and destruction reactions of PCDDs in OCDD-added fly ash heated under vacuum

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