70648-23-6Relevant articles and documents
Role of copper chloride in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans during incineration
Hatanaka, Takeshi,Kitajima, Akio,Takeuchi, Masao
, p. 73 - 79 (2007/10/03)
Combustion experiments in a laboratory-scale fluidized-bed reactor were performed to elucidate the role of copper chloride in formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) during model waste incineration. The amounts of PCDDs and PCDFs formed, the homologue profiles, and the isomer distributions were measured in the flue gas from incineration of model wastes containing various levels of copper. A correlation was found between the Cu content of the waste and the proportion of each congener. An increase in copper enhanced the formation of certain congeners, showing that copper acts as a catalyst for formation of PCDDs and PCDFs. An increase in the copper content of the waste decreased the CO concentration in the flue gas and reduced the formation of PCDDs and PCDFs during incineration. This indicates that copper also works as an oxidation catalyst to promote combustion, leading to lower concentrations of products of incomplete combustion. It is indispensable to consider both roles of the catalyst, i.e., enhancement and suppression, in the formation of PCDDs and PCDFs during waste incineration, which are estimated separately from the isomer distributions and the amounts of PCDDs and PCDFs formed.
De novo synthesis mechanism of polychlorinated dibenzofurans from polycyclic aromatic hydrocarbons and the characteristic isomers of polychlorinated naphthalenes
Iino,Imagawa,Takeuchi,Sadakata
, p. 1038 - 1043 (2007/10/03)
Polychlorinated dibenzofurans (PCDFs) and polychlorinated naphthalenes (PCNs) are known to be emitted from municipal waste incinerators (MWIs) with polychlorinated dibenzo-p-dioxins (PCDDs). Two formation paths for PCDD/Fs could mainly work, which are condensation of the precursors such as chlorophenols and 'de novo' formation from carbon. However the correlation between the chemical structure of carbon and the resulting PCDD/Fs still remains unknown. In this study, the PCDD/Fs formation from polycyclic aromatic hydrocarbons (PAHs) and CuCl was examined at 400 under 10% O2. Coronene among the PAHs characteristically gave 1,2,8,9-T4CDF and the derivatives. These isomers clearly indicate that chlorination causes the cleavage of the C-C bonds in a coronene molecule and also that oxygen is easily incorporated from its outside to form 1,2,8,9-T4CDF. The symmetrical preformed structures in the coronene molecule enabled to amplify the de novo formation of the isomer. PCNs are also formed directly from these PAHs. Since there have been few reports on the formation mechanism of PCNs, this study will be a first step to know the whole formation paths. We also define the de novo synthesis as the breakdown reaction of a carbon matrix, since the word has been used without the precise definition.
