Portal de Periódicos da CAPES

Measurements of Octanol−Air Partition Coefficients for Polychlorinated Biphenyls

1996; American Chemical Society; Volume: 41; Issue: 4 Linguagem: Inglês

10.1021/je960097y

1520-5134

Tom Harner, Terry F. Bidleman,

Chemical Thermodynamics and Molecular Structure

The octanol−air partition coefficient, KOA, is measured for 15 polychlorinated biphenyls (PCBs) over the temperature range −10 °C to +30 °C using a generator column method. The enthalpy of phase change from octanol to air, H, is calculated for 18 PCBs and ranges from 66 to 90 kJ/mol. Enthalpy of dissolution of the liquid phase PCB in octanol, ΔSOLH, calculated as ΔVAPH − H, has a mean value of 6.6 kJ/mol (n = 18) and there is no correlation of ΔSOLH with homolog group or number of ortho-substituted chlorine atoms. Results show that KOA values increase within a homolog group for congeners having fewer ortho chlorine atoms. A log10 − log10 correlation of KOA against liquid-phase vapor pressure (poL) shows enhanced partitioning into octanol for mono- and non-ortho congeners. Separate regressions for non/mono-ortho and multi-ortho groups allow KOA to be estimated for other congeners.