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Physical & Chemical properties

Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Study period:
2020
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Qualifier:
according to
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Version / remarks:
Computational approach in OECD Guideline 107
Deviations:
no
Principles of method if other than guideline:
Firstly, the water solubility (based on CMC) and n-octanol solubilities of the test substance were determined according to OECD Guidelines 115 and 105 respectively. The partition coefficient was then calculated from ratio of the solubility of the test substance in octanol and water.
GLP compliance:
no
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water
Analytical method:
other: Computational approach
Key result
Type:
Pow
Partition coefficient:
ca. 332.88
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and water/CMC
Key result
Type:
log Pow
Partition coefficient:
ca. 2.52
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and water/CMC
Details on results:
-Based on the results of the read across study, the solubility of the test substance in n-octanol is considered to be 243 g/L (ref: Brekelmans, 2012)
-Solubility of the test substance in water (based on CMC): 0.73 g/L (ref: Mangnus, 2019)

The log Pow was calculated according to the equation:
Pow = solubility of the test substance in n-octanol / solubility of the test substance in water

Pow calculation based on n-octanol solubility:
= 243 g/L / 0.73 g/L
= 332.88
Log Pow: 2.52
Conclusions:
Under the study conditions, the calculated partition coefficient (log Pow) of the test substance, based on solubility in n-octanol and water, is calculated to be 2.52 at 20°C.
Executive summary:

A study was conducted to determine partition coefficient of the test substance, Coco TMAC from the ratio of the solubility in n-octanol and water, which is recommended for surface active substances according to OECD Guideline 107. The water solubility of the test substance was determined to be 0.73 mg/L (based on critical micelle concentration) and the n-octanol solubility based on a read across study was determined to be 243 g/L. The Pow and log Pow calculations based on solubility ratio is determined to be 332.88 and 2.52 respectively. Under the study conditions, the calculated partition coefficient (log Pow) of the test substance, based on solubility ratio in n-octanol and water, is calculated to be 2.52 at 20°C (KLK Kolb, 2020).

Description of key information

The partition coefficient of the test substance was calculated using the ratio of individual solubilities in n-octanol and water (i.e., based on critical micelle concentration (CMC)), a method which is recommended for surface active substances according to OECD Guideline 107 (KLKL Kolb, 2020). 

Key value for chemical safety assessment

Log Kow (Log Pow):
2.52
at the temperature of:
20 °C

Additional information

(based on ratio of n-octanol solubility and critical micelle concentration)