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Physical & Chemical properties

Partition coefficient

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Description of key information

Partition coefficient Log Kow = 0.79 (+/-0.48) (estimated)
Worst-case for CSA due to dissociation.
Low potential for bioaccumulation.

Key value for chemical safety assessment

Log Kow (Log Pow):
0.79
at the temperature of:
25 °C

Additional information

An experimental study was provided, that was disregarded as the substance was dissociated under the test conditions.

The partition coefficient of TFA was therefore estimated using QSAR calculation. Three models, using different methodologies, were run, one was considered as valid, the two others not assignable. As a general rule, QSARs refer to the undissociated form of the molecule (log Kow definition), except for SPARC, which calculates log D as a function of pH; for this model, the value at pH=0 was retained, to allow comparison. A total of 10 consistent results was obtained, within the range 0.21-1.78, which is significantly below the threshold of 4, with regard to classification criteria (long-term aquatic toxicity). The arithmetical mean value of these 10 results (0.79 +/-0.48) will be retained. It should also be noticed that this mean is consistent with the value of the valid QSAR (0.50 +/-0.48).

However, it should be noted that this is not relevant at environmental pH range, where it is well-known that ionised substances are less lipophilic and less adsorbed. This is confirmed by the lower experimental value (-4.1), and the data obtained with SPARC model (-0.58 at pH 5.5 and above). Nevertheless, the theoretical log Kow is retained as a worst-cas key value for the CSA.