Chlorinated naphthalene formation from the oxidation of dichlorophenols.
Polychlorinated naphthalenes (PCNs) formed along with dibenzo-p-dioxin and dibenzofuran products in the slow combustion of dichlorophenols (DCPs) at 600 degrees C were identified. Each DCP reactant produced a unique set of PCN products. Major PCN congeners observed in the experiments were consistent with products predicted from a mechanism involving an intermediate formed by ortho-ortho carbon coupling of phenoxy radicals; polychlorinated dibenzofurans (PCDFs) are formed from the same intermediate. Tautomerization of the intermediate and H2O elimination produces PCDFs; alternatively, CO elimination to form dihydrofulvalene and fusion produces naphthalenes. Only trace amounts of tetrachloronaphthalene congeners were formed, suggesting that the preferred PCN formation pathways from chlorinated phenols involve loss of chlorine. 3,4-DCP produced the largest yields of PCDF and PCN products with two or more chlorine substituents. 2,6-DCP did not produce tri- or tetra-chlorinated PCDF or PCN congeners. It did produce 1,8-DCN, however, which could not be explained.
Kim
Do Hyong
DH
Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0512, USA.
Mulholland
James A
JA
Ryu
Jae-Yong
JY
D000393:Air Pollutants / Q000032:analysis*; D001572:Benzofurans / Q000032:analysis / Q000737:chemistry; D002733:Chlorophenols / Q000737:chemistry*; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D007536:Isomerism; D008956:Models, Chemical; D009281:Naphthalenes / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D013696:Temperature
D000393:Air Pollutants; D001572:Benzofurans; D002733:Chlorophenols; D000072338:Dibenzofurans, Polychlorinated; D006843:Hydrocarbons, Chlorinated; D009281:Naphthalenes; D010636:Phenols; C042329:phenoxy radical