Photolysis of mono- through deca-chlorinated biphenyls by ultravioletirradiation in n-hexane and quantitative structure-propertyrelationship analysis
LI Xue , FANG Lei , HUANG Jun , YU Gang
DOI:
Received August 13, 2007,Revised October 15, 2007, Accepted , Available online
Volume 20,2008,Pages 753-759
- Summary
- References
- Related Articles
The photolysis of 16 polychlorinated biphenyls (PCBs) (including mono- through deca-chlorinated) in n-hexane was investigated
under ultraviolet irradiation using a 500-W high-pressure mercury lamp. Photolysis of PCBs follows pseudo-first-order reaction
kinetics, with photolysis rate constants ranging between 0.0011 s-1 for PCB-52 and 0.0574 s-1 for PCB-118. The degradation rates of
PCBs by high-pressure mercury lamp irradiation were remarkably independent with respect to the degree of chlorination. Furthermore,
partial least squares (PLS) models were developed to provide insight into which aspect of the molecular structure influenced PCB
photolysis rate constants. It was found that the photolysis rates of PCBs increased with an increase in the net charge on the carbon
atom (qC), (ELUMO–EHOMO)2, and the Y-axis dipole moment ( y) values, or the decrease in the energy of the second highest occupied
molecular orbital (EHOMO-1), energy of the lowest unoccupied molecular orbital (ELUMO), ELUMO + EHOMO, ELUMO – EHOMO, most
positive atomic charge (q+), and the twist angle of the chlorine atom (TA) values.
