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EC number: 201-944-8 | CAS number: 89-83-8
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- data from handbook or collection of data
- Principles of method if other than guideline:
- no data
- GLP compliance:
- no
- Type of method:
- other: measured
- Partition coefficient type:
- octanol-water
- Type:
- log Pow
- Partition coefficient:
- 3.3
- Remarks on result:
- other: Temperature and pH are not reported
- Conclusions:
- The log Pow of thymol is 3.3.
- Executive summary:
Hansch et al. reported in 1995 in the article " Exploring QSAR. Hydrophobic, Electronic, and Steric Constants." ( ACS Professional Reference Book. American Chemical Society, Washington, DC.) that the log Pow of thymol is determined experimentally to be 3.3.
- Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Study period:
- 14 JAN 2021
- 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
EPWIN v4.1 implemented in OECD QSAR Toolbox v4.4
2. MODEL (incl. version number)
KOWWIN v1.68
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CC(C)c1ccc(C)cc10
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please refer to attached QMRF
5. APPLICABILITY DOMAIN
Please refer to attached QPRF - Guideline:
- other: ECHA guidance R.6
- Principles of method if other than guideline:
- - Software tool(s) used including version:
EPWIN v4.1 implemented in OECD QSAR Toolbox v4.4
- Model(s) used: KOWWIN v1.68
- Model description: see field 'Justification for non-standard information', 'Attached justification'
- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' - Type of method:
- calculation method (fragments)
- Partition coefficient type:
- octanol-water
- Specific details on test material used for the study:
- CC(C)c1ccc(C)cc10
- Type:
- log Pow
- Partition coefficient:
- 3.52
- Remarks on result:
- other: Temperature and pH not specified in the model
- Details on results:
- The substance falls within the applicability domain of the model.
- Conclusions:
- The log Kow was predicted to be 3.52. The predicted value falls within the applicability domain of the model.
- Executive summary:
The log octanol-water partition coefficient (log Kow) for thymol was predicted using the QSAR model KOWWIN v1.68 implemented in the Estimation Program Interface (EPI) Suite v 4.1 (US EPA 2010). The log Kow was predicted to be 3.52. The predicted value falls within the applicability domain of the model.
Referenceopen allclose all
Description of key information
Hansch et al. reported in 1995 in the article " Exploring QSAR. Hydrophobic, Electronic, and Steric Constants." ( ACS Professional Reference Book. American Chemical Society, Washington, DC.) that the log Pow of thymol is determined experimentally to be 3.3.
The log octanol-water partition coefficient (log Kow) for thymol was predicted using the QSAR model KOWWIN v1.68 implemented in the Estimation Program Interface (EPI) Suite v 4.1 (US EPA 2010). The log Kow was predicted to be 3.52. The predicted value falls within the applicability domain of the model.
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 3.3
- at the temperature of:
- 20 °C
Additional information
Since one result found in handbook data may not adequately fulfill the requirements for data quality for this endpoint, it was completed by QSAR estimation with a scientifically validated and reliable model. The substance falls within the applicability domain of the model, results are adequate for risk assessment and the applied method is adequate and reliably documented.
Handbook data and QSAR estimation are evaluated in a weight-of-evidence approach and experimentally derived handbook data are shown to be comparable to the estimation. Since experimental data are expected to be even more reliable than calculated ones these are used as key data and taken forward to risk assessment.
Furthermore, using the slightly lower experimental log Kow from handbook data has no significant influence on risk assessment, e.g. RCR <1 or PBT assessment. Furthermore no temperature was given in the handbook data and in the calculation model, but room conditions (20 - 25 °C) can be assumed. For the chemical assessment the temperature was set to 20 °C.
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