Vapor pressures of six brominated diphenyl ether congeners.

Subcooled liquid vapor pressures (PLo) of six polybrominated diphenyl ether (PBDE) congeners containing three to seven bromine atoms were determined using the gas chromatograph retention time technique. Values ranged from 2.3 x 10(-7) to 1.45 x 10(-4) Pa at 25 degrees C. An increase in the number of bromine atoms tended to decrease PLo according to the correlation log PLo = -0.692 (bromine number)--1.76 (R2 = 0.953, p < 0.001). In addition, the first such data for individual PBDE congeners demonstrates that PLo would vary four orders of magnitude over environmentally relevant temperatures.