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Diss Factsheets

Physical & Chemical properties

Partition coefficient

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Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1. SOFTWARE
EPI Suite v4.10 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
KOWWIN v1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See information as provided in "Overall remarks, attachments" section.

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.
Principles of method if other than guideline:
Calculation based on KOWWIN v1.68, Estimation Programs Interface Suite™ for Microsoft® Windows v4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.
GLP compliance:
no
Type of method:
other: QSAR
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
9.91
Remarks on result:
other: QSAR result, no information available on temperature and pH

-------+-----+--------------------------------------------+---------+--------

 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE

-------+-----+--------------------------------------------+---------+--------

 Frag | 1 | -CH3   [aliphatic carbon]               | 0.5473 | 0.5473

 Frag | 20 | -CH2-  [aliphatic carbon]               | 0.4911 | 9.8220

 Frag | 1 | -COOH  [acid, aliphatic attach]         |-0.6895 | -0.6895

 Const |    | Equation Constant                        |        | 0.2290

QSAR result; pH and temperature are not reported.

Conclusions:
The substance fits in the applicability domain of the model. The prediction is valid and can be used for classification and risk assessment.
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
GLP compliance:
yes
Type of method:
flask method
Partition coefficient type:
octanol-water
Analytical method:
gas chromatography
Type:
log Pow
Partition coefficient:
> 5.11
Temp.:
25 °C
Remarks on result:
other: no information about pH

Concentration in n-octanol and water phases under three conditions (mg/L):                        
-----------------------------------
Condition                Run 1                Run 2
      Water phase  Octanol phase   Water phase  Octanol phase
-----------------------------------
1         <0.0237       3,040          <0.0237      3,070
2         <0.0237       1,520          <0.0237      1,550
3         <0.0237         739          <0.0237        803
-----------------------------------
The concentration of the test substance in water phase was below the detection limit (< 0.0237 mg/L).

No information is given on temperature and pH.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
results derived from a (Q)SAR model, with limited documentation / justification
Justification for type of information:
No further information available
Principles of method if other than guideline:
company data, no information is given on estimation method
GLP compliance:
not specified
Type of method:
other: estimated
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
> 5
Remarks on result:
other: no information about temperature and pH

company data, no information is given on temperature and pH.

Description of key information

9.91 at 25 °C

Key value for chemical safety assessment

Log Kow (Log Pow):
9.91
at the temperature of:
25 °C

Additional information

The value for partition coefficient log Kow is determined based on a weight of evidence approach using experimental data (OECD 107, shake flask method) and QSAR data (EPI Suite KOWWIN and one unknown model).

The substance belongs to a class of "difficult-to-test" hydrophobic substances, because it contains a long alkyl chain in the molecule. The calculated log Kow complies with the general trend of partition coefficient for the fatty acids of the chain length between C6 and C22 - the values increase with increasing chain length. The substance is compliant with the applicability domain of the KOWWIN model. Therefore the predicted value of log Kow for docosanoic acid (which is in agreement with experiment and company QSAR data where only the lower limits are estimated) can be accepted for chemical safety assessment.