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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
Study period:
2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Guideline compliant water solubility and solubility in organic solvent studies were used for the calulation of Log Kow. Individual solubilities i.e., octanol solubility was divided by the value of water solubility/CMC and the Log of this value would correspond to Log Kow
Reason / purpose for cross-reference:
reference to other study
Reason / purpose for cross-reference:
reference to other study
Principles of method if other than guideline:
Since the test substance is a surface active material, the partition coefficient was determined by the estimation method using the n-octanol solubility of the test substance and the critical micelle concentration ratio.
GLP compliance:
yes
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water
Key result
Type:
Pow
Partition coefficient:
1 208.3
Temp.:
25 °C
Remarks on result:
other: calculated value based on individual solubilities
Key result
Type:
log Pow
Partition coefficient:
3.08
Temp.:
25 °C
Remarks on result:
other: calculated value based on individual solubilities
Details on results:
Under the conditions of the study, the octanol solubility of the test substance was determined to be 290 g/L at 23°C (Farnback, 2012).
Under the conditions of the study, the CMC of the test substance was determined to be 0.24 g/L or 240 mg/L at 25°C ± 0.5°C (Börjesson, 2012).

The Pow, calculated as the quotient of the n-octanol- and critical micelle concentration, is 1208.3. It corresponds with a log Pow value of 3.08.

See above results and discussion for details

Conclusions:
Under the study conditions, the partition coefficient (Pow) of the test substance was determined to be 1208.3 at 25°C. This corresponds to a log Pow value of 3.08.



Executive summary:

A study was conducted to determine the partition coefficient of the test substance, C16 TMAC (Purity: 95.6%) using an estimation method based on n-octanol solubility and critcal micelle concentration (CMC) ratios. Since the test substance is surface-active, the CMC is used as an alternative to the water solubility.The octanol solubility of the test substance was determined to be 290 g/L at 23°C (Farnback, 2012) and the CMC was determined to be 0.24 g/L at 25°C ± 0.5°C (Börjesson, 2012). Under the study conditions, the partition coefficient (Pow) of the test substance was determined to be 1208.3 at 25°C. This corresponds to a log Pow value of 3.08 (Stepan, 2012).

Description of key information

The partition coefficient of the surface-active test substance was determined by using an estimation method based on n-octanol solubility and critical micelle concentration ratios (Börjesson, 2012; Farnback, 2012). 

Key value for chemical safety assessment

Log Kow (Log Pow):
3.08
at the temperature of:
25 °C

Additional information

(calculated using n-octanol solubility of 290 g/L at 23°C and CMC of 0.24 g/L at 25°C)