Study on Photolysis Pathways of PCBs by UV Irradiation in Alkaline 2-Propanol

This study aiming at elucidating the photolysis pathways of PCBs by UV irradiation was designed to explore the photolytic characteristics of several PCBs including 2, 4, 4'-TriCB, 2, 2', 5-TriCB and 2, 2', 5, 5'-TetraCB in alkaline 2-propanol solution and to define their respective photolysis pathways. The results show that the chlorine atom at the ortho- position tends to be released more readily than those at the para- or at the meta- position during photochemical process and that the reductive dechlorination pathways in alkaline alcohol do not alter with the changes in UV wavelength and reaction solvents, whereas the PCB isomers are significantly affected by chlorine substitution position and greatly differ in their rates of photolysis.