Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
TU Berlin, Institut für Lebensmittelchemie und -technologie, Berlin, Germany.
Environ Sci Pollut Res Int. 2019 Jun;26(16):15838-15846. doi: 10.1007/s11356-019-04815-w. Epub 2019 Apr 5.
1,3,5-Tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione (TDBP-TAZTO) is an emerging brominated flame retardant which is widely used in several plastic materials (electric and electronic equipment, musical instruments, automotive components). However, until today, no photochemical studies as well as the identification of possible phototransformation products (PTPs) were described in literature. Therefore, in this study, UV-(C) and simulated sunlight irradiation experiments were performed to investigate the photolytic degradation of TDBP-TAZTO and to identify relevant PTPs for the first time. The UV-(C) irradiation experiments show that the photolysis reaction follows a first-order kinetic model. Based on this, the photolysis rate constant k as well as the half-life time t were calculated to be k = (41 ± 5 × 10) min and t = (17 ± 2) min. In comparison, a minor degradation of TDBP-TAZTO and no formed phototransformation products were obtained under simulated sunlight. In order to clarify the photochemical behavior, different chemicals were added to investigate the influence on indirect photolysis: (i) HO for generation of hydroxyl radicals and (ii) two quenchers (2-propanol, sodium azide) for scavenging oxygen species which were formed during the irradiation experiments. Herein, nine previously unknown PTPs of TDBP-TAZTO were detected under UV-(C) irradiation and identified by HPLC-(HR)MS. As a result, debromination, hydroxylation, and dehydrobromination reactions could be presumed as the main degradation pathways by high-resolution mass spectrometry. The direct as well as the OH radical-induced indirect photolysis were observed. Graphical abstract .
1,3,5-三-(2,3-二溴丙基)-1,3,5-三嗪-2,4,6-三酮（TDBP-TAZTO）是一种新兴的溴化阻燃剂，广泛应用于多种塑料材料（电子和电气设备、乐器、汽车部件）中。然而，直到今天，文献中还没有描述过任何光化学研究以及可能的光转化产物（PTPs）的鉴定。因此，在这项研究中，首次进行了 UV-(C) 和模拟阳光照射实验，以研究 TDBP-TAZTO 的光解降解，并鉴定相关的光转化产物。UV-(C) 辐照实验表明，光解反应遵循一级动力学模型。基于此，计算了光解速率常数 k 和半衰期 t，分别为 k = (41 ± 5 × 10) min 和 t = (17 ± 2) min。相比之下，在模拟阳光照射下，TDBP-TAZTO 的降解程度较小，没有形成光转化产物。为了阐明光化学行为，添加了不同的化学物质来研究间接光解的影响：(i) HO 用于生成羟基自由基，(ii) 两种猝灭剂（异丙醇、叠氮化钠）用于清除辐照实验中形成的氧物种。在此，在 UV-(C) 辐照下检测到了 TDBP-TAZTO 的九个以前未知的光转化产物，并通过 HPLC-(HR)MS 进行了鉴定。结果表明，脱溴、羟化和脱氢溴化反应可以被推测为通过高分辨率质谱确定的主要降解途径。观察到了直接和 OH 自由基诱导的间接光解。
