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Physical & Chemical properties

Partition coefficient

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Description of key information

Log Pow = 2.67 (fragment method;

Log Pow >1 according to log (solubility in n-octanol / solubiliy in water)

Key value for chemical safety assessment

Log Kow (Log Pow):
2.67
at the temperature of:
20 °C

Additional information

A reliable study (RL1) compliant with GLP and considering relevant technical guidelines (OECD 107; OECD 117; EU-method A.8) was performed to determine the partition coefficient n-octanol/water (Pow) for the test item. Neither the HPLC-method according to OECD Guideline No. 117 nor the flask-shaking method according to OECD Guideline No. 107 were applicable for the determination of the partition coefficient of the test item. As described in the guidelines the flask shaking test is only applicable to water and n-octanol soluble substances. Therefore, based on the very low solubility of test item in water and in n-octanol the test could not be performed. A HPLC-method was not available.

Thus, the log Pow-value for the test item was

a) estimated from its solubility in n-octanol and in water as well as

b) calculated using a model calculation based on the theoretical fragmentation of the molecule into substructures.

According to a), in the present study, the n-octanol solubility of the test item was determined to be 0.195 mg/L. The water solubility of the test item was determined under RCC Project 742421 to be < 0.02 mg/I. Thus, the partition coefficient, log Pow, of of the test item was calculated to be:

log Pow = log (0.195 mg/L / <0.02 mg/L) = >1

As the water solubility is stated "below quantification limit", the true log Pow must be somewhat higerh than the value obtained with individual solubilities (i.e. >1). Therefore,

according to b), the log Pow of the test item was estimated by a model calculation based on the theoretical fragmentation of the molecule into suitable structures for which reliable log Pow values were used. The final result was obtained by summing the fragment values and the correction terms, resulting in log Pow = 2.7 for the test item.

In conclusion,the log Pow of the test item was estimated to be log Pow = 2.7using a model calculation, which is based on theoretical fragmentation.