Details

Autor(en) / Beteiligte

• Wang, Yao
• Huang, Jinbao
• Wang, Hong
• Lan, Lin
• Mu, Xin
• Xu, Weiwei
• Lv, Shanjin
• Li, Xinsheng

Titel

Theoretical study on pyrolysis mechanism of decabromodiphenyl ether (BDE-209) using DFT method

Ist Teil von

• Chemosphere (Oxford), 2023-01, Vol.310, p.136904-136904, Article 136904

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Decabromodiphenyl ether (BDE-209), as a brominated flame retardant (BFR), is widely applied to various consumer products due to its superior performance and affordable pricing to improve the flame resistance of materials. To better comprehend the pyrolysis behavior of BDE-209 and the evolution process of main pyrolysis products, the thermal degradation mechanism of BDE-209 was studied using density functional theory (DFT) method at the theoretical level of M06/cc-pVDZ, and thermodynamic parameters were calculated in this paper. Unimolecular degradation was dominated by cleavage of the ether linkage, which results in a high yield of hexabromobenzene, and fission of the ortho-position C–Br bond is the main competitive reaction channel. In the system of BDE-209 + H, the pyrolysis reaction is majorly characterized by debromination, leading to the formation of considerable HBr and low-brominated diphenyl ethers. Additionally, the hydrogen-derived splitting of the ether bond acts as a mainly competitive channel, which is the source of polybromophenols and polybromobenzenes. The formation of polybrominated dibenzofuran (PBDF) derives from the cyclization reaction of ortho-phenyl-type radicals, which are readily generated through the ortho-position Br atom abstraction by H radical. The formation of polybrominated dibenzo-p-dioxin (PBDD) involves the ortho-C-O coupling reaction of polybromophenoxy radicals, debromination reaction, and cyclization reaction. And the total yield of PBDD/Fs was significantly increased when H was involved. Results presented in this work will provide the helpful information for the treatment and reuse of BDE-209-containing waste plastics through using pyrolysis technology. The density functional theory method M06 with the cc-pVDZ basis set has been used to investigate the pyrolysis mechanisms of decabromodiphenyl ether (BDE-209) in this study. Hexabromobenzene (HBBz), octabromodibenzo-p-dioxin (OBDD), octabromodibenzofuran (OBDF), and Br2 are the major products for unimolecular decomposition of BDE-209. Polybrominated diphenyl ethers (PBDEs), polybrominated phenols (PBPhs), polybrominated benzenes (PBBzs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and HBr are the main products for pyrolysis of BDE-209 with H radicals. [Display omitted]