Vapor pressures of the polybrominated diphenyl ethers

The supercooled liquid vapor pressures P-L of 23 polybrominated diphenyl ether congeners were determined as a function of temperature with a gas chromatographic retention time technique. P-L at 298.15 K ranged from 0.1 Pa for monobrominated diphenyl ethers to 10(-6) Pa for heptabrominated diphenyl ethers. The halogen substitution pattern was found to influence PBDE vapor pressure, indicating,that congeners with bromine substitutions in the ortho positions to the ether-link have higher vapor pressures; The enthalpy of vaporization Delta H-vap for the 23 PBDE congeners ranged from (-67 to -116) kJ/mol, decreasing with each additional bromine substitution by about (7 to 8) kJ(.)mol(-1). Delta H-vap was also found to be influenced by the number of ortho bromines. Using a Junge-Pankow approach, the fraction of chemical adsorbed to aerosols as a function of temperature was estimated for three congeners and used to speculate on the likely environmental behavior of these chemicals.