title: Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies.
abstract: 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.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University , Jiangsu Nanjing 210023, PR China.|College of Chemistry and Chemical Engineering, Xinyang Normal University , Henan Xinyang 464000, PR China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University , Jiangsu Nanjing 210023, PR China.
authors.forename: Ruijuan
authors.initials: R
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University , Jiangsu Nanjing 210023, PR China.
authors.forename: Mingbao
authors.initials: M
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University , Jiangsu Nanjing 210023, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University , Jiangsu Nanjing 210023, PR China.
authors.forename: Liansheng
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University , Jiangsu Nanjing 210023, PR China.
authors.forename: Zunyao
authors.initials: Z
authors.lastname: Wang
mesh_terms: D007700:Kinetics; D008962:Models, Theoretical; D010636:Phenols / Q000737:chemistry; D010782:Photolysis; D012997:Solvents / Q000737:chemistry*
chemical_list: D010636:Phenols; D012997:Solvents