In:
Canadian Journal of Chemistry, Canadian Science Publishing, Vol. 91, No. 6 ( 2013-06), p. 398-405
Abstract:
The density functional theory (DFT) has been applied to studies on the homogeneous gas-phase degradation of 2,3,7,8-tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TeCDD) initiated by the NO 3 radical, which is an important atmospheric species at night. The geometrical parameters and vibrational frequencies of all the stationary points were calculated at the MPWB1K/6-31+G (d,p) level. Potential energies were calculated at the MPWB1K/6-311+G (3df,2p) level. Three sites on 2,3,7,8-TeCDD react with the NO 3 radical with different barriers and reaction heats. The addition of NO 3 to the carbon atom on the central C–O ring is the most appropriate pathway and with the lower barriers, and the central ring of polychlorinated dibenzo-p-dioxin is opened in the subsequent reactions. Some other pathways are stressed for the dechlorination mechanism. Canonical variational transition-state theory with small curvature tunneling contribution was used to calculate the rate constants of each elementary reaction over the temperature range of 200–400 K. The Arrhenius equations were fitted to show the relationship between rate constants and temperature.
Type of Medium:
Online Resource
ISSN:
0008-4042
,
1480-3291
DOI:
10.1139/cjc-2012-0443
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
2013
detail.hit.zdb_id:
1482256-8
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