Photolytic Transformation Products of Decabromodiphenyl Ethane (DBDPE)

Abstract

The photolytic transformation of decabromodiphenyl ethanea current-use brominated flame retardant and major substitute of the structurally related decabromodiphenyl etherwas investigated in different solvents (toluene, dichloromethane, chlorobenzene, and benzyl alcohol). The transformation rate followed pseudo first order kinetics, with increasing half-life (t 1/2) in the order of toluene (t 1/2 = 4.6 min), chlorobenzene (t 1/2 = 14.0 min), dichloromethane (t 1/2 = 27.9 min), and benzyl alcohol (t 1/2 ≈ 60 min). Formation and amount of transformation products varied depending on the solvent used. A detailed study of the hydrodebromination products allowed us to tentatively assign all three possible nonaBDPEs (BDPE 207, 208, and in benzyl alcohol only BDPE 206) and three predominant octaBDPE congeners (BDPE 197, 201, and 202). Next to the reported BDPEs, formation of several oxygen containing transformation products (OxyTPs), dominated by octabrominated OxyTP, was verified by GC-Orbitrap-HRMS analysis. Use of HPLC and Florisil column enabled the separation of OxyTPs and BDPEs, and the polybrominated OxyTPs were most likely tricyclic compounds with almost planar structure.

Combining In Silico Tools with Multicriteria Analysis for Alternatives Assessment of Hazardous Chemicals: Accounting for the Transformation Products of decaBDE and Its Alternatives

“…These two compounds are both much more bioaccumulative and mobile in the aquatic environment compared to their parent compound decaBDE (Table S10). PentaBDE was included as a photodegradation product of decaBDE, and based on the literature, DBDPE can also photodegrade and form bromodiphenyl ethanes substituted with five to eight bromines. , This suggests the importance of including photodegradation and the need to develop prediction tools to cover this pathway.…”

Full Characterization of the UV Hydrodebromination Products of the Current-Use Brominated Flame Retardants Hexabromobenzene, Pentabromotoluene, and Pentabromoethylbenzene

“…UV irradiation experiments were performed at 20 ± 0.5 °C using a medium-pressure mercury vapor lamp (150 W, type TG 150, Heraeus Noblelight, Hanau, Germany) with an effective spectral range of 200–300 nm as described before. , To ensure consistent irradiation, the lamp was switched on 15 min before the experiment was started. In brief, a quartz cell, equipped with 650 μL of cuBFR solution (i), which corresponded with ∼130 μg per compound, was placed in front of the lamp (kept distance: 8 cm).…”

“…Samples were analyzed on a 7890/5975C MSD system (Agilent, Waldbronn, Germany) equipped with a 30 m × 0.25 mm i.d., 0.25 μm d f Optima 5 MS capillary column (Macherey-Nagel, Düren, Germany). Operating conditions were set as described before . For specific tribromotoluene separation, the GC oven program was exclusively adjusted and started at 80 °C for 1 min.…”

“…The MS was either operated in full-scan ( m / z 50–800) or SIM mode (Table S2). PBT, which is the monomeric form of DBDPE, was additionally analyzed on a 15 m × 0.25 mm i.d., 0.1 μm Rtx-1 column to check the possible formation of BDPEs as described before …”

“…The intrinsically low stability of C–Br bonds led to the discovery that BFRs like PBBs, PBDEs, and decabromodiphenyl ethane (DBDPE) were prone to UV transformation into lower-brominated congeners and reaction byproducts, which could be more toxic than the precursor BFR itself. − Likewise, Bendig et al showed that HBB was easily transferred into pentabromobenzene by sunlight . Similarly, Ling et al studied the phototransformation of DBDPE, bis­(2-ethylhexyl) tetrabromophthalate (TBPH), HBB, and PBT using different light sources, two temperatures, and different solvents along with humic substances to imitate aquatic conditions .…”