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Physical & Chemical properties

Partition coefficient

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Description of key information

log Pow > 4

Key value for chemical safety assessment

at the temperature of:
20 °C

Additional information

The value for partition coefficient log Pow of the substance is based on a weight of evidence using QSAR results for the components of the substance. The testing in this case is difficult, because it is a surface active substance, and it is a UVCB. Due to the complex nature of the UVCB substance, not all constituents of the substance are known. For the evaluation of the influence of the dimerisation and branching, the hypothetical structures were examined with the use of QSAR model (KOWWIN v1.68).

The calculated partition coefficient log Pow for main monomers constituting the substance are all above 6: log Pow=7.87 for mono-branched isooctadecanoic acid, 7.94 for octadecanoic acid, and 6.96 for hexadecanoic acid. The partition coefficient of the substance increases with the chain length incrementally. Log Pow of the dimer of C18 fatty acids is then expected to be much higher than log Pow of monomers. It is also proven by QSAR prediction for example dimer structure (log Pow = 14.81). The log Pow is not substantially affected by branching and it was calculated by KOWWIN v1.68 for an example structure of C18 acid (octamethyldecanoic acid) to be 7.36. All available results show that the log Pow of isooctadecanoic acid (UVCB) is high and well above 4. Therefore log Pow >4 cut-off value is accepted for the chemical safety assessment.