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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
accepted calculation method
Reason / purpose for cross-reference:
assessment report
Reason / purpose for cross-reference:
assessment report
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
Version / remarks:
Technically not feasible to measure the partition coefficient with OECD 107, therefore the individual solubility of the test substance in 1-octanol will be measured according to OECD 105.
GLP compliance:
no
Remarks:
Not applicable
Type of method:
estimation method (solubility ratio)
Remarks:
Ratio between the experimental solubility in water and experimental value of solubility in a saturated octanol solution
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
4.29
Temp.:
20 °C
Remarks on result:
other: Calculation is provided in 'Any other information on results incl. tables'

Due to technical difficulties, the partition coefficient was not measured according to a standard guideline. Instead, it was calculated using the ratio between the experimental values of solubility in a saturated Octanol solution and solubility in water according to REACH Guidance R7a.


The water solubility of the substance was determined to be 2.30 µg/L at 20 ˚C using the column elution method in accordance with OECD TG 105 and in compliance with GLP (Arkema 2013). The mean 1-octanol solubility for the test substance at 20 ºC was 44.7 ± 0.88 mg/L using the shake flask method following OECD TG 105 and EPA OPPTS 830.7840, and compliance with GLP (Eurofins 2021).


The Kow of the substance at 20 ˚C = the solubility of the substance in 1-octanol at 20 ˚C / the solubility of the substance in water at  20 ˚C = 44.7 mg/L / 2.30 µg/L = 19434.78


Thus, LogKow = 4.29

Conclusions:
The LogKow of the test substance was calculated to be 4.29 at 20 ˚C using the ratio between the experimental solubility in water and the experimental value of solubility in a saturated 1-Octanol solution.
Executive summary:

Due to technical difficulties, the partition coefficient was not measured according to a standard guideline. Instead, it was calculated using the ratio between the experimental values of solubility in a saturated Octanol solution and solubility in water according to REACH Guidance R7a. The water solubility of the substance was determined to be 2.30 µg/L at 20 ˚C using the column elution method following OECD TG 105 and in compliance with GLP (Arkema 2013). The mean 1-octanol solubility for the test substance at 20 ºC was 44.7 ± 0.88 mg/L using the shake flask method following OECD TG 105 and EPA OPPTS 830.7840, and in compliance with GLP (Eurofins 2021). Based on these results, the Kow of the substance at 20 ˚C was calculated to be 19434.78, and LogKow was 4.29.

Description of key information

The LogKow of the test substance was calculated to be 4.29 at 20 ˚C using the ratio between the experimental solubility in water and the experimental value of solubility in a saturated 1-Octanol solution.

Key value for chemical safety assessment

Log Kow (Log Pow):
4.29
at the temperature of:
20 °C

Additional information

Due to technical difficulties, the partition coefficient was not measured according to a standard guideline. The difficulties and efforts that have been taken to overcome these difficulties are addressed in two expert statements. These statements are included as references in the study record. The partition coefficient was calculated using the ratio between the experimental values of solubility in a saturated Octanol solution and solubility in water according to REACH Guidance R7a.


The water solubility of the substance was determined to be 2.30 µg/L at 20 ˚C using the column elution method following OECD TG 105 and in compliance with GLP (Arkema 2013). The mean 1-octanol solubility for the test substance at 20 ºC was 44.7 ± 0.88 mg/L using the shake flask method following OECD TG 105 and EPA OPPTS 830.7840, and in compliance with GLP (Eurofins 2021). Based on these results, the Kow of the substance at 20 ˚C was calculated to be 19434.78, and LogKow was 4.29.