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EC number: 946-061-5 | CAS number: -
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Type of information:
- calculation (if not (Q)SAR)
- Remarks:
- Migrated phrase: estimated by calculation
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- Generally accepted calculation method; according to ECHA Guidance R7a: Guidance on regulatory compliant Kow determination for surfactants: "In many cases a calculated Kow value based on the octanol and water solubilities will be the first choice for surfactants. (...) A working approach for surfactants might be the comparison of measured solubilities in octanol and water. However, it would then be prudent to take the critical micelle concentration in water (CMC) as a solubility limit, in order to avoid the artefact of unrealistically low Kow values"
- Qualifier:
- according to guideline
- Guideline:
- EU Method A.8 (Partition Coefficient)
- Version / remarks:
- Appendix 1 Calculation method
- GLP compliance:
- no
- Type of method:
- other: calculation method using the density of the substance and the CMC determination in water
- Partition coefficient type:
- octanol-water
- Type:
- log Pow
- Partition coefficient:
- 4.8
- Temp.:
- 20 °C
- Remarks on result:
- other: Value calculated using the relative density and the CMC concentration in water
- Details on results:
- As it was not possible to determine an exact value of the solubility of the substance in n-octanol, it's density at 20°C is used instead. In this regard, the density is used as the maximum concentration that could be achieved.
On the other hand, instead of using the solubility in water for the calculation, the Critical Micelle Concentration is used instead, as it is regarded as more representative of the behaviour of the substance in water. This approach is recommended in ECHA Guidance R7a "Guidance on regulatory compliant Kow determination for surfactants". - Conclusions:
- The log Kow of the substance is calculated to be 4.8 at 20 °C
- Executive summary:
The Log Kow can be calculated according to EC440/2008, A.8, from the solubilites in the pure solvents in the case of surfactans. However in this particular case, and due to the experimental difficulties found, this approach has been adapted.
As it was not possible to determine and exact value of the solubility of the substance in n-octanol, it's density at 20°C is used instead. in this regard, the density is used as the maximum concentration that could be achieved.
On the other hand, instead of using the solubility in water for the calculation, the Critical Micelle Concentration is used instead, as it is regarded as more representative of the behaviour of the substance in water. This approach is recommended in ECHA Guidance R7a "Guidance on regulatory compliant Kow determination for surfactants".
As a result, the log Kow of the substance is calculated to be 4.8 at 20 °C
- Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- 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 limited documentation / justification
- Type:
- log Pow
- Partition coefficient:
- 3.55
- pH:
- 7
- Remarks on result:
- other: MarvinSketch logD
- Remarks:
- QSAR for SMILES: O=C(O)COCCOCCOCCCCCCCCC=CCCCCCCCC
- Conclusions:
- According to MarvinSketch QSAR calculation, for the main entity (carboxylate with C18') at pH=7, the logD = 3.55
- Executive summary:
According to MarvinSketch QSAR calculation, for the main entity (carboxylate with C18') at pH=7, the logD = 3.55
Referenceopen allclose all
Log Kow = log (density / CMC)
density at 20°C: 0.9464 g/cm3 = 9.464e5 mg/L
CMC (Critical Micelle Concentration) at 20°C: 16 mg/L
Log Kow = Log (9.464e5 / 16) = log 59150 = 4.77
Description of key information
Based on solubilities, the logKow was determined via calculation method to be 4.77 at 20 °C.
pH of measurements is not reported resp. cannot be determined for solubility in octanol. As the main constituent is a acid/base active substance (carboxylate), pH determines logKow: at high pH the substance is only as a anion in solution, resulting in a low logKow. At very low pH, the substance is not ionised, resulting in a high logKow. For solubility in water, critical micell concentration was used; the solubility in octanol was estimated as a worst case based on densitiy.
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 4.77
- at the temperature of:
- 20 °C
Additional information
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