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Physical & Chemical properties

Partition coefficient

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Description of key information

log P at ca. 23 °C: 5.7 (OECD TG117, solubility ratio calculation)

Key value for chemical safety assessment

Log Kow (Log Pow):
5.7
at the temperature of:
23 °C

Additional information

The water and n-octanol solubilities on which the log P estimate is based were measured using scientifically valid methods and were conducted under GLP. The solubility ratio method was applied due to the difficulty of accurate measurement of FC-770 concentrations in aqueous samples at the level necessary to conduct a shake-flask or slow-stirring method. Suitable reference standards for an HPLC determination of the log P are not available, nor are QSAR methods applicable to highly fluorinated chemicals due to lack of an appropriate training set. The solubility ratio method, while an estimate, provides a reasonable value of partition coefficient. The sources of error in extending solubility ratio to Pow, i.e. the activities of the substance in water and n-octanol and the dependence of activity on concentration, tend to cancel each other out in the case of hydrophobic substances(1). Therefore, this study is classified as reliable with restrictions. An additional estimate of log Pow, obtained using the Rekker QSAR method, could not be classified as to reliability since the algorithm training set could not be evaluated.

 

1) S. H. Yalkowsky, S. C. Valvani, T. J. Roseman. 1983. Solubility and Partitioning VI: Octanol Solubility and Octanol-Water Partition Coefficients. J. Pharm. Sci. Vol. 72, No. 8, pp. 866-870.