Important role of reaction field in photodegradation of deca-bromodiphenyl ether: theoretical and experimental investigations of solvent effects.
Photolysis of deca-bromodiphenyl ether (BDE-209) was investigated in tetrahydrofuran, dichloromethane, isopropanol, acetone, ethanol, methanol, acetonitrile and dimethylsulfoxide. Noticeable differences of the photolytic rates and quantum yields were found in the diverse solvents. Different to the previous deductions, hydrogen donating efficiency and electron donating efficiency of solvents were not the decisive factors for the photolytic rate in this study, which was proved by the fast photolysis of BDE-209 in CCl(4), a solvent without hydrogen and difficult to donate electrons. Besides hydrogen addition process, intermolecular polymerization might occur during the photolysis. Density functional theory (DFT) calculation was performed to understand the molecular properties of BDE-209 in different solvents. The lowest singlet vertical excitation energy (E(ex)) and the average formal charge on Br (q(Br)(+)) of BDE-209, reflecting the difficulty for the excitation of BDE-209 and for the departing of Br atom, respectively, were changed by the reaction fields formed by the different solvents. E(ex) and q(Br)(+) linearly correlated with the photolytic activity (logk). This study is helpful to better understand the photolytic behavior of BDE-209 in different media.
Xie
Qing
Q
Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), Department of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China.
Chen
Jingwen
J
Shao
Jianping
J
Chen
Chang'er
C
Zhao
Hongxia
H
Hao
Ce
C
D019840:2-Propanol / Q000737:chemistry; D000096:Acetone / Q000737:chemistry; D000097:Acetonitriles / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D005411:Flame Retardants; D005663:Furans / Q000737:chemistry; D055768:Halogenated Diphenyl Ethers / Q000737:chemistry*; D007700:Kinetics; D000432:Methanol / Q000737:chemistry; D008752:Methylene Chloride / Q000737:chemistry; D008956:Models, Chemical; D010782:Photolysis; D012997:Solvents / Q000737:chemistry*
D000097:Acetonitriles; D004785:Environmental Pollutants; D005411:Flame Retardants; D005663:Furans; D055768:Halogenated Diphenyl Ethers; D012997:Solvents; D000096:Acetone; D000431:Ethanol; C018674:tetrahydrofuran; D008752:Methylene Chloride; C010902:decabromobiphenyl ether; D019840:2-Propanol; D000432:Methanol; D004121:Dimethyl Sulfoxide; C032159:acetonitrile