PBDE 15 is a polybrominated di-?Ph ether (PBDE), which is a flame retardant often incorporated into many polymers. PBDEs are an environmental pollutant that exhibit potential health risks to humans and wildlife.
The general procedure for the synthesis of 4,4'-dibromodiphenyl ether from diphenyl ether was as follows: in a four-necked round-bottomed flask fitted with a stirrer, condenser, dropping funnel and thermometer, diphenyl ether (170 g, 1.0 mol), 1,2-dichloroethane (EDC) (300 ml), water (200 ml) and NaBrO3 (55 g, 0.36 mol) were added. Bromine (176 g, 1.1 mol) was slowly added dropwise to the stirred mixture for 1 h at 25 °C. No significant HBr gas was released during the reaction. The reaction progress was monitored by gas chromatography (GC). After two hours of reaction, the diphenyl ether was completely converted to 4,4'-dibromodiphenyl ether. The reaction was stopped and the phases were separated to give the crude product 4,4'-dibromodiphenyl ether (324.8 g) in 99% yield and 99.5% selectivity.
[1] Patent: EP429975, 1991, A1
[2] Angewandte Chemie - International Edition, 2018, vol. 57, # 20, p. 5938 - 5942
[3] Angew. Chem., 2018, vol. 130, p. 6044 - 6049,6
[4] Monatshefte fuer Chemie, 1992, vol. 123, # 12, p. 1153 - 1162
[5] Patent: EP429975, 1991, A1
