TY - JOUR
T1 - Mechanisms for the formation of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) from chlorinated toluenes
AU - Rawadieh, Saleh
AU - Altarawneh, Mohammednoor
AU - Altarawneh, Ibrahem
AU - Al-Shaweesh, Mouath A.
N1 - Funding Information:
Acknowledgments This study has been supported by a grant of computing time from the National Computational Infrastructure (NCI), Australia.
PY - 2014/8
Y1 - 2014/8
N2 - In this contribution, we study a new mechanism of the formation of PCDD/F polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) from chlorinated toluenes, using quantum chemical calculations. Pathways involving 2-chlorotoluene incur high activation barriers which diminish its direct role in the formation of PCDD/F. Alternatively, the 2-chlorobenzyl and 2-methylphenoxy radicals, which are important intermediates in the early stages of the 2-chlorotoluene oxidation, yield PCDD/F through a less energy demanding pathway. The proposed mechanisms resemble the well-established pathways for the oxidative coupling of chlorinated phenols. It is predicted that the presence of an ortho methyl-bearing site facilitates initial coupling over that of an ortho chlorinebearing site. Furthermore, chlorinated toluenes may initially be oxidized to phenoxy and phenolic intermediates to form PCDD/F. Results presented herein should be instrumental for gaining a better understanding of general formation routes of PCDD/F.
AB - In this contribution, we study a new mechanism of the formation of PCDD/F polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) from chlorinated toluenes, using quantum chemical calculations. Pathways involving 2-chlorotoluene incur high activation barriers which diminish its direct role in the formation of PCDD/F. Alternatively, the 2-chlorobenzyl and 2-methylphenoxy radicals, which are important intermediates in the early stages of the 2-chlorotoluene oxidation, yield PCDD/F through a less energy demanding pathway. The proposed mechanisms resemble the well-established pathways for the oxidative coupling of chlorinated phenols. It is predicted that the presence of an ortho methyl-bearing site facilitates initial coupling over that of an ortho chlorinebearing site. Furthermore, chlorinated toluenes may initially be oxidized to phenoxy and phenolic intermediates to form PCDD/F. Results presented herein should be instrumental for gaining a better understanding of general formation routes of PCDD/F.
KW - Chlorinated toluenes
KW - PCDD/Fs
KW - Quantum Chemistry
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U2 - 10.1007/s11144-014-0710-6
DO - 10.1007/s11144-014-0710-6
M3 - Article
AN - SCOPUS:84906053350
SN - 1878-5190
VL - 112
SP - 321
EP - 333
JO - Reaction Kinetics, Mechanisms and Catalysis
JF - Reaction Kinetics, Mechanisms and Catalysis
IS - 2
ER -