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Partition coefficient

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Description of key information

log Pow – experimental value: 7.50 (OECD 117, HPLC method)  
log Pow - calculated from weight-averaged log Koc value: 6.84 (calculation based on 2003 EU TGD)
log Pow - calculated using KOWWIN v1.68 (weight-averaged value): 7.11 (EPIsuite v4.11)

Key value for chemical safety assessment

Log Kow (Log Pow):

Additional information

The log Pow of 7.5 for the substance (Z)-9 -Octadecen-1-ol, ethoxylated, < 2.5 EO (CAS 9004-98-2) was determined experimentally using the HPLC method according to OECD Guideline 117. This method has only limited validity for this type of compounds.

According to the approach developed for the Alcohol Ethoxylate Category, the value for chemical safety assessment logPow = 7.15 is derived in a weight-of-evidence approach on the basis of various log Pow values (average of 3 values: experimental 7.5; calculated 6.84 and 7.11).


The following types of calculations were applied:

1. based on weight-averaged log Koc values using the TGD equation for predominantly hydrophobic substances: log Koc = 0.81 log Pow + 0.10 thus log Pow = (log Koc – 0.10)/0.81 (2003 EU Technical Guidance Document on Risk Assessment Part III, Chapter 4, Section 4.3, pp 24 – 27)

2. based on EPIsuite v 4.10, KOWWIN v 1.68 log Pow values for (possible) individual constituents of the substance; a weighting based on normalized composition was applied to derive a log Pow value for the whole substance. Only the weight-averaged value was used as input value for derivation of the key value for chemical safety assessment.