Measurement of vapor pressures of some selected polybrominated aromatic flame retardants and evaluation of vapor pressure estimation models

Yui, K.; Motoki, T.; Kato, H.; Kajiwara, N.; Kuramochi, H.; Sakai, S.; Wania, F. (2018) Proceedings of 38th International Symposium on Halogenated Persistent Organic Pollutants, pp. 1186

Introduction: Brominated flame retardants (BFRs) are used in a variety of industrial products, household appliances, and transport vehicles. Although there are clearly benefits associated with the use of flame retardants, some BFRs such as polybrominated diphenyl ethers (PBDEs) with 4 to 7 bromines are recognized as persistent organic pollutants (POPs). Recently, novel BFRs are emerging to replace the banned POPs. It is of importance to evaluate the fate of such novel BFRs in the environment and to identify the compounds that have POP-like characteristics. To estimate the environmental fate of novel BFRs, knowledge of physicochemical properties such as vapor pressure is required. Unfortunately, their vapor pressures are not currently available. In this study, the vapor pressures of five non-PBDE BFRs including 1,2,4,5-tetrabromo-3,6-dimethylbenzene (TBX), 1,2,3,4,5-pentabromo-6-methylbenzene (PBT), 2,3,4,5,6-pentabromoethylbenzene (PBEB), 2,3,4,5,6-pentabromophenol (PBP), and 2,4,6-tribromophenyl 2,3-dibromopropyl ether (TBP-DBPE) were measured using the gas saturation method. We selected these compounds because they would be more likely to be emitted to the atmosphere than other novel BFRs. The new vapor pressure data were also used to evaluate the predictive performance of a number of existing methods (equations and programs) for vapor pressure estimation for those compounds.