1,2-Bis(2,4,6-tribromophenoxy)ethane (BTBPE) is currently one of the most commonly applied novel brominated flame retardants. In this contribution, we analyze in detail the mechanisms pertinent to its thermal decomposition in view of analogous experimental findings. We demonstrate that a 1,3-hydrogen shift, leading to 2,4,6-tribromophenol (M9) and 1,3,5-tribromo-2-(vinyloxy)benzene (M10) molecules, dominates direct scission of O-CH2 bonds up to a temperature of approximately 680 K. H atom abstraction from CH2 sites, followed by a fission of a C-C bond, produce a 2,4,6-tribromophenoxy radical (M2) and a M10 molecule. Bimolecular condensation reactions involving M2, M9, and M10 generate several congeners of brominated diphenyl ethers and their OH/OCHCH2 substituents, which serve as direct precursors for the formation of polybrominated dibenzo-p-dioxins. Reaction of M9 with a model compound of a hydrocarbon chain preferentially yields M2. Strong adsorption energy of the latter on a radical site of a hydrocarbon chain suggests that mechanisms such as Langmuir-Hinshelwood, Eley-Rideal, and Diels-Alder might be operating during the formation of PBDD/Fs from brominated flame retardants (BFRs). Reactions of alkyl primary/secondary radicals and diradical with the BTBPE molecule proceed via H abstraction from a -CH2- moiety.

中文翻译：

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新型溴化阻燃剂1,2-双（2,4,6-三溴苯氧基）乙烷（BTBPE）的热分解。

1,2-双（2,4,6-三溴苯氧基）乙烷（BTBPE）当前是最常用的新型溴化阻燃剂之一。在此贡献中，我们将根据类似的实验结果详细分析与其热分解有关的机制。我们证明，导致1,2,4,6-三溴苯酚（M9）和1,3,5-三溴-2-（乙烯基氧基）苯（M10）分子的1,3-氢转移，主导了O-CH2的直接断裂氢键最多可达到约680 K的温度。从CH2位置提取H原子，然后裂开CC键，产生2,4,6-三溴苯氧基（M2）和M10分子。涉及M2，M9和M10的双分子缩合反应会生成溴化二苯醚及其OH / OCHCH2取代基的多个同类物，它们是形成多溴二苯并-对-二恶英的直接前体。M9与烃链模型化合物的反应优先产生M2。后者在烃链自由基位点上的强大吸附能表明，在由溴化阻燃剂（BFR）形成PBDD / F的过程中，诸如Langmuir-Hinshelwood，Eley-Rideal和Diels-Alder之类的机制可能起作用。烷基伯/仲基和双自由基与BTBPE分子的反应是通过从-CH2-部分中夺取H进行的。Diels-Alder可能在由溴化阻燃剂（BFR）形成PBDD / F的过程中运行。烷基伯/仲基和双自由基与BTBPE分子的反应是通过从-CH2-部分中夺取H进行的。Diels-Alder可能在由溴化阻燃剂（BFR）形成PBDD / F的过程中运行。烷基伯/仲自由基和双自由基与BTBPE分子的反应是通过从-CH2-部分中夺取H进行的。