Vapor pressure of solid polybrominated diphenyl ethers determined via Knudsen effusion method.

Polybrominated diphenyl ethers (PBDEs) are flame retardants used in a variety of consumer products. The solid vapor pressures of BDE 15 and BDE 209 were determined by using the Knudsen effusion method, and the values measured extrapolated to 298.15 K are 3.12 × 10(-3) and 9.02 × 10(-13) Pa, respectively. The enthalpies of sublimation for these compounds have also been estimated by using the Clausius-Clapeyron equation and are 102.0 ± 3.5 and 157.1 ± 3.5 kJ/mol, respectively. In addition, the melting points and enthalpies of fusion were measured by differential scanning calorimetry.