Abstract:

Polybrominated biphenyls (PBBs) are a class of new type organic pollutants. They have been
widely used as flame retardants to reduce the fire risk on plastics, carpets, electronic equipment,
textiles and building materials around the world. With a gas chromatographic retention time
technique, vapor pressures (p) of six polybrominated biphenyls (PBB15, PBB26, PBB31, PBB49, PBB103
and PBB153) were determined as a function of temperature with dichlorodiphenyl trichloroethane (DDT)
acting as a reference substance. Vapor pressures at 298.15 K ranged from 0.01 Pa for dibrominated
biphenyl to 10-6 Pa for hexabrominated biphenyl. According to these vapor pressures at different
temperatures, Antoine parameters (A, B, C) of six PBBs were regressed with the least square method.
The correlations between vapor pressure and temperature for six PBBs were obtained. In addition, the
correlations between vapor pressures and molecular connectivity indexes have been studied with
correlation coefficients greater than 0.99 and standard errors less than 0.08. The vapor pressures
of PBBs were also estimated by their molecular connectivity indexes.

Key words: Antoine
equation, molecular connectivity indexes , polybrominated biphenyls (PBBs), vapor pressure, as chromatography (GC)