Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany; TU Berlin, Institut für Lebensmitteltechnologie und Lebensmittelchemie, Gustav-Meyer-Allee 25, D-13305, Berlin, Germany.
Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany.
Chemosphere. 2019 Aug;229:77-85. doi: 10.1016/j.chemosphere.2019.04.184. Epub 2019 Apr 28.
In this study the direct and indirect photolysis of the novel brominated flame retardant 2,4,6-Tris-(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) in an organic solvent mixture (60:30:10, ACN:MeOH:THF) under UV-(C) and simulated sunlight irradiation was investigated, and the formed photo-transformation products were identified for the first time. TTBP-TAZ was almost completely degraded within 10 min under UV-(C) irradiation. Due to the fast degradation no specific kinetic order could be observed. In comparison, the reaction under simulated sunlight irradiation was much slower and thus, the kinetic first-order could be determined. The observed photolysis rate constant k as well as the half-life time t were estimated to be k = (0.0163 ± 0.0002) h and t = 42.3 h, respectively. The addition of 2-propanol and hydrogen peroxide to investigate the influence of indirect photolysis under UV-(C) irradiation causes no influence on the degradation of TTBP-TAZ. Nevertheless, the removal of TTBP-TAZ under UV-(C) and simulated sunlight without additional chemicals (except solvent) indicates that the direct photolysis plays a significant role in the degradation mechanism of TTBP-TAZ. In both irradiation experiments, TTBP-TAZ was quantitatively degraded that involve the formation of previously unknown PTPs. Overall, two main PTPs were determined when irradiated with UV-(C) and eight sequential debromination products were observed when irradiated by simulated sunlight. These were determined by HPLC-DAD and - MS/(MS), respectively. Based on the chosen experimental conditions the consecutive debromination as well as photo-Fries rearrangement was confirmed as the main degradation pathway by high resolution mass spectrometry and X-ray diffraction.
在本研究中，在有机溶剂混合物（ACN:MeOH:THF 为 60:30:10）中，通过紫外线（C）和模拟阳光照射，研究了新型溴化阻燃剂 2,4,6-三-(2,4,6-三溴苯氧基)-1,3,5-三嗪（TTBP-TAZ）的直接和间接光解，并且首次鉴定了形成的光转化产物。在紫外线（C）照射下，TTBP-TAZ 在 10 分钟内几乎完全降解。由于快速降解，无法观察到特定的动力学顺序。相比之下，模拟阳光照射下的反应要慢得多，因此可以确定动力学一级。观测到的光解速率常数 k 和半衰期 t 分别估计为 k = (0.0163 ± 0.0002) h 和 t = 42.3 h。在紫外线（C）照射下研究间接光解的影响时，添加 2-丙醇和过氧化氢对 TTBP-TAZ 的降解没有影响。然而，在没有添加额外化学物质（溶剂除外）的情况下，TTBP-TAZ 在紫外线（C）和模拟阳光下的去除表明直接光解在 TTBP-TAZ 的降解机制中起着重要作用。在这两种辐照实验中，TTBP-TAZ 被定量降解，涉及形成以前未知的 PTPs。总体而言，当用紫外线（C）照射时，确定了两种主要的 PTP，当用模拟阳光照射时，观察到了八个连续的脱溴产物。这分别通过 HPLC-DAD 和 - MS/(MS) 确定。基于所选的实验条件，通过高分辨率质谱和 X 射线衍射证实了连续脱溴和光-Fries 重排是主要的降解途径。
