Octanol–air partition coefficients of polybrominated biphenyls

The octanol–air partition coefficients (KOA) for PBB15, PBB26, PBB31, PBB49, PBB103 and PBB153 were determined as a function of temperature using a gas chromatographic retention time technique with 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (p,p′-DDT) as a reference substance. The internal energies of phase change from octanol to air (ΔOAU) were calculated for the six compounds and were in the range from 74 to 116 kJ mol−1. Simple regression equations of log KOA versus relative retention times (RRTs) on gas chromatography (GC), and log KOA versus molecular connectivity indexes (MCI) were obtained, for which the correlation coefficients (r2) were greater than 0.985 at 283.15 K and 298.15 K. Thus the KOA values of the remaining PBBs can be predicted by using their RRTs and MCI according to these relationships.