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(156) Reactivity of brominated diphenyl ethers vs. methane thiolate. Rahm, Sara1, Jakobsson, Eva1,2, 1 2 ABSTRACT- Polybrominated diphenyl ethers (PBDEs) are used as additive flame retardants in e.g. computers, TV-sets and textiles. Today, the PBDEs are widespread in the environment and present also in humans. The aim of the present study was to study the reactivity of some of the major PBDEs in the environment towards nucleophilic displacement, 2,2,3,3,4,4,5,5,6,6-Decabromodiphenyl ether (BDE-209), 2,2,3,4,4,5,6-heptabromodiphenyl ether (BDE-183), 2,2,4,4,5-pentabromodiphenyl ether (BDE-99) and 2,2,4,4-tetrabromodiphenyl ether (BDE-47) were treated with solutions of methantiolate in tetrahydrofuran. The reaction mixtures were stirred at room temperature for 48 h. Aliquots were collected after 1, 2 and 24 h. and analysed by gas chromatography and gas chromatography-mass spectrometry (GC-MS). The reactivity of the PBDEs were found to be BDE-209>BDE-183>BDE-99>BDE-47, i.e. the reactivity was correlated to the bromination degree of the compounds. BDE-209 was remarkably reactive, being completely transformed already after 1 hour. After the same reaction time, 40 % of the BDE-183 had transformed while BDE-99 and BDE-47 remained intact. The reaction products were identified as lower brominated PBDEs and methylthio-PBDEs. Minor products resulting from the cleavage of the ether bridge was identified from BDE-209. Key words: brominated flame retardant, nucleophile, reactivity |
