POLYCHLORINATED NAPHTHALENE (PCN) AND DIBENZOFURAN (PCDF) CONGENER PATTERNS
FROM PHENOL PRECURSORS IN THERMAL PROCESS: [II] EXPERIMENTAL RESULTS FROM DICHLOROPHENOLS (DCPs)
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Jae-Yong Ryu1†, Do Hyong Kim2, Kum-Chan Choi3, and Jeong-Min Suh4 |
1Environmental Research Team, Daegu-Gyeongbuk Development Institute, Daegu, Korea 2Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA 3Department of Environmental Engineering, Dong-A University, Pusan, Korea 4Department of Regional Environmental System Engineering, Pusan National University, Miyrang, Korea |
Corresponding Author:
Jae-Yong Ryu ,Tel: +82-53-770-5112, Fax: +82-53-770-5069, Email: jyryu@dgi.re.kr |
Received: March 8, 2006; Accepted: May 11, 2006. |
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ABSTRACT |
Polychlorinatecl naphthalenes (PCNs) formed along with dibenzo-p-dioxin and dibenzofuran products in the slow combustion of dichlorophenols (DCPs) at 600°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 interemediate. Tautomerization of the intermediate and H?0 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. |
Keywords:
Municipal waste incinerator | Thermal process | Combustion | Polychlorinated Naphthalenes | Polychlorinated Dibenzofurans | Chlorophenol |
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