title: Formation Pathways of Mono- to Octa-Chlorinated Dibenzo-p-dioxins and Dibenzofurans in Main Organochemical Industries.
abstract: The concentrations and formation pathways of mono- to octa-chlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were investigated in main organochemical industries. High levels of PCDDs and PCDFs were detected. The total concentrations of 27 PCDD/F congeners in chloranil, 2,4-D, and 1,4-dichlorobenzene were 5302397 ± 8944449, 20963 ± 15908, and 242 ± 67 pg g(-1), respectively, and the less-chlorinated PCDD/F levels were 12006 ± 20155, 9536 ± 5594, and 195 ± 94 pg g(-1), respectively. The distribution trends of less and more chlorinated PCDD/Fs were similar in different chemical plants because of their similar formation pathways, which may also be related to the degree of chlorination of chemical products and purification processes. 1,2,3,4-TeCDF and 2,4,8-TrCDF were selected as model molecules to calculate the bond dissociation energy, showing that 2-MCDF, 3-MCDF, and 2,8-DCDF are more easily formatted as shown by the analytical results. The formation pathways of less to more chlorinated PCDFs are proposed to explain why 2-MoCDF, 2,8-DiCDF, 2,4,8-TrCDF, and 2,3,4,7,8-PeCDF are the dominant congeners and to explain why 2,3,4,7,8-PeCDF is the largest contributor of I-TEQs in most studies.
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Ying
authors: Y
authors: Han
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Wenbin
authors: W
authors: Liu
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Wenxiao
authors: W
authors: Pan
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Pu
authors: P
authors: Wang
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Zhenyu
authors: Z
authors: Tian
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Yuyang
authors: Y
authors: Zhao
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Mengjing
authors: M
authors: Wang
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Xuebin
authors: X
authors: Chen
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Xiao
authors: X
authors: Liao
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Beijing 100085, China.
authors: Minghui
authors: M
authors: Zheng
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis*; D054879:Halogenation; D007221:Industry; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D013816:Thermodynamics
chemical_list: D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; C023614:dibenzofuran