Measurement of Temperature Dependence for Vapor Pressures of Seventeen OH-PBDEs and Eleven MeO-PBDEs by Gas Chromatographic Method

Abstract

Hydroxylated polybromodiphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are emerging organic pollutants. Supercooled liquid vapor pressures (p L) and enthalpies of vaporization (∆vap H) for seventeen OH-PBDEs and eleven MeO-PBDEs were determined by a gas chromatographic technique. p L at 298 K ranged from 0.0173 Pa for 2'-OH-BDE3 to 2.32 × 10(-7) Pa for 3'-OH-BDE154 and they are approximately one order of magnitude smaller than those determined for the counterpart polybrominated diphenyl ethers (PBDEs). ∆vap H was in the range of 76-121 kJ/mol. The temperature dependence of p L was measured by fitting the experimental data with the log(p L/Pa) = a/(T/K) + b equation, and this corresponds to a 50-265 times higher p L value at 0 versus 30°C. Using fundamental quantum chemical descriptors, two quantitative structure-property relationship models (Q cum > 0.935) were developed to estimate p L at any temperature for the additional OH- and MeO-PBDE congeners.

Measurement of Vapor Pressures and Melting Properties of Five Polybrominated Aromatic Flame Retardants

“…So far, the GC-RT method has been used to determine subcooled liquid vapor pressures for PBDEs − and hexabromobenzene (HBB), whereas the vapor pressures of PBDEs, − HBCDs, HBB, tetrabromobisphenol A (TBBPA), , and 1,2-bis­(2,4,6-tribromophenoxy)­ethane (BTBPE) have been measured using either the Knudsen effusion ,, or the gas saturation method . As for other brominated aromatic compounds, the vapor pressures of polybrominated dibenzo- p -dioxins (PBDDs), derivatives of BFRs, and brominated aromatic compounds with fewer Br substituents − have also been measured using the Knudsen effusion method, ,− , gas saturation method, , or other static methods using a manometer. , Besides vapor pressures, water solubilities, 1-octanol/water partition coefficients, and Henry’s law constants of BFRs have also been measured or estimated, and we have previously reported experimentally determined properties other than vapor pressure for TBBPA, brominated phenols, brominated benzenes, and PBDEs …”