Mechanism of formation of polychlorinated dibenzo-p-dioxins and dibenzfurans in the catalyzed combustion of carbon. Luijk, R.; Akkerman, D.M.; Slot, P.C.; Olie, K.; Kapteijn, F. Published in:Environmental Science and Technology DOI:10.1021/es00051a019Link to publication Citation for published version (APA):Luijk, R., Akkerman, D. M., Slot, P. C., Olie, K., & Kapteijn, F. (1994). Mechanism of formation of polychlorinated dibenzo-p-dioxins and dibenzfurans in the catalyzed combustion of carbon. Environmental Science and Technology, 28, 312-321. DOI: 10.1021/es00051a019 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Combustion experiments of an activated carbon (Norit RX Extra), catalyzed by CuC12, were conducted in triplicate in a flow of moist air containing 5 vol % HC1 at 300 "C to reveal the mechanism of formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The catalyst concentration was varied from 0, 0.1,0.5,1.0, to 5.0 wt %. After partial combustion (1 h), the samples were analyzed on the presence of PCDDs and PCDFs. The total yield of these compounds amounted to 19 (0.1 wt % CuC12) and 2 (5.0 wt % CuClz) pg/g of carbon. The PCDD/PCDF ratio showed a decrease from 33 to 0.2. At low copper concentrations, predominantly PCDDs are formed with an isomer pattern that can be explained completely as a product of chlorophenol condensation reactions. At high copper concentrations, the PCDD/PCDF isomer distribution pattern shifts toward a characteristic waste incineration fly ash pattern. A proposal for the mechanism of formation of PCDDs and PCDFs in the catalyzed combustion of carbon will be presented. Condensation reactions of 2,4,6-trichlorophenol on carbon ( O w t 9% CuC12)

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