多溴联苯醚
化学
热解
溴
卤化
质谱法
有机化学
药物化学
环境化学
色谱法
污染物
作者
Jiahao Liang,Rui Wang,He Li,Danping Xie,Xueqin Tao,Jiangmin Zhou,Hua Yin,Zhi Dang,Guang-Hong Lü
出处
期刊:Chemosphere
[Elsevier]
日期:2022-12-01
卷期号:308: 136246-136246
被引量:7
标识
DOI:10.1016/j.chemosphere.2022.136246
摘要
This study presents the comprehensive investigation for formation pathways of chloro-bromo-mixed products from the pyrolysis of polybrominated diphenyl ethers (PBDEs). In the study, a total of 23 PBDEs with bromination levels from mono-to deca-were selected. Each PBDE standard was sealed in the glass vial and then heated under 450 °C in the muffle furnace to simulate the pyrolysis process. The results demonstrated that PBDEs in the glass vials can unintentionally transform into chloro-bromo diphenyl ethers (PBCDEs) and dibenzo-p-dioxin and dibenzofurans (PBCDD/Fs) during the pyrolysis process. Atmosphere pressure gas chromatography (APGC) coupled with high-resolution mass spectrometry (HRMS) was used to identify these pyrolysis products, which demonstrated that all investigated nPBDEs (n represents the number of bromine substituents) can unintentionally transform into Cl1-(n-1)BDEs, Cl2-(n-2)BDEs, Cl1-(n-1)BDFs, and Cl1-(n-3)BDDs, while some nPBDEs can transform into Cl1-(n-2)PBDD/Fs during pyrolysis. Experimental phenomena assisted with density functional theory (DFT) calculations reveal that Cl atom can substitute at C-Br rather than C-H, and Cl1-(n-1)BDEs can be easily generated by Cl atom attacking at C-Br sites with low energy barriers (3.66-11.9 kcal/mol). In addition, nPBDEs with lower bromination levels are more favorable to generate Cl1-(n-1)BDEs than those with higher bromination levels. Further DFT calculations suggest that PBDEs are preferentially first transformed into Cl1-(n-1)BDEs, then subsequentially transform into PBCDD/Fs. We believe the results of this study can greatly improve our understanding of the transformation mechanism from PBDEs to cholo-bromo-mixed products in thermal treatment processes and provide new insight into controlling the emission of toxic cholo-bromo-mixed products.
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