Behavior and prediction of photochemical degradation of chlorinated polycyclic aromatic hydrocarbons in cyclohexane.
The photochemical degradation of 11 chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and the corresponding 5 parent PAHs was examined to simulate the compound's fate on aerosol surfaces. All the ClPAHs and PAHs decayed according to the first-order reaction rate kinetics. The photolysis rates of ClPAHs varied greatly according to the skeleton of PAHs; the rates of chlorophenanthrenes (ClPhes) and 1-chloropyrene were higher than those of corresponding parent PAHs, whereas chlorofluoranthenes, 7-chlorobenz[a]anthracene and 6-chlorobenzo[a]pyrene were more stable under irradiation compared to respective parent PAH. Considering the photoproducts of ClPhes detected, the oxidation could occur immediately at positions of the highest frontier electron density. Finally, the quantitative structure-property relationship models were developed for direct photolysis half-lives and average quantum yields of the ClPAHs and parent PAHs, in which the significant factors affecting photolysis were E(LUMO+1), total energy and surface area, and E(LUMO), E(LUMO)-E(HOMO) and total energy, respectively.
Ohura
Takeshi
T
Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan. ooura@smail.u-shizuoka-ken.ac.jp
Amagai
Takashi
T
Makino
Masakazu
M
D003510:Cyclohexanes / Q000737:chemistry; D004785:Environmental Pollutants / Q000528:radiation effects; D006843:Hydrocarbons, Chlorinated / Q000528:radiation effects*; D008958:Models, Molecular; D010782:Photolysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000528:radiation effects*; D021281:Quantitative Structure-Activity Relationship; D012997:Solvents / Q000737:chemistry; D014466:Ultraviolet Rays
D003510:Cyclohexanes; D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D011084:Polycyclic Aromatic Hydrocarbons; D012997:Solvents; C506365:Cyclohexane