Registration Dossier

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The method is similar to the EC and OECD guidelines. The test conditions are sufficiently described but the GLP are not mentioned.
Qualifier:
no guideline followed
Principles of method if other than guideline:
HPLC method
GLP compliance:
not specified
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
1.62
pH:
2.2
Remarks on result:
other: no data on temperature

Measured Log k' (10%) = -0.41
The corresponding Log P is 1.62.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The method followed the new OECD guideline 122 (proposal) "Partition coefficient (n-Octanol/Water), pH-metric method for ionisable substances". As only few information on the test conditions and the result obtained is available (i.e. no repeated determination results), the result is considered as reliable with restrictions.
Qualifier:
according to
Guideline:
other: OECD 122 pH-metric method
GLP compliance:
not specified
Partition coefficient type:
octanol-water
Analytical method:
other: Potentiometric analysis
Type:
log Pow
Partition coefficient:
1.41
Temp.:
23 °C
pH:
> 3 - < 11.5

LogP = 1.41 (+/-) 0.03
Remark: 
Octanol and water used in the study were not mutually presaturated. 

To  test the consequence of mutual solubility, the solubility data were applied for 

corrections to octanol and water volumes. The authors were not sure the correction was valid 

since mutual saturation proceeds slowly  whereas the analysis takes no more than 10 minutes. 

The corrected values for the test substance is as follows:
pKa = 10.06 +/- 0.01
logP = 1.35 +/- 0.03

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Even if the method is not considered as a standard EC or OECD test guideline, the test conditions are relatively well described to assess its validity.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Microemulsion electrokinetic chromatography (MEEKC)
GLP compliance:
not specified
Type of method:
other: Microemulsion electrokinetic chromatography (MEEKC)
Partition coefficient type:
octanol-water
Analytical method:
other: Microemulsion electrokinetic chromatography (MEEKC)
Type:
log Pow
Partition coefficient:
1.23
pH:
7
Remarks on result:
other: no data on temperature

Migration index obtained: MI = 4.02
Partition coefficient deduced: Log P = 1.23

The correlation was expressed by:
log P = 0.518 MI - 0.854
n = 53, r = 0.996, s = 0.094, F = 6083
where r is the correlation coefficient, s is the standard deviation from  

regression, and F the value of the F-ratio between regression and  residual variances.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: The data has been obtained according to the HPLC method but very few information is available about the test conditions (temperature, pH, mobile phase, detection). Therefore, it is not possible to assess the reliability of this study.
Qualifier:
no guideline followed
Principles of method if other than guideline:
HPLC method
GLP compliance:
not specified
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
1.3
Remarks on result:
other: no data on temperature and pH

no more data available

Description of key information

Literature values range from 1.13 to 1.62

Key value for chemical safety assessment

Log Kow (Log Pow):
1.3
at the temperature of:
20 °C

Additional information

Seven data on logKo/w with reliability scores of 2 and 4 are available and give values within the narrow range from 1.13 to 1.62. These have been used in a weight of evidence approach.

Moreover, 4-methoxyphenol is one of the substances recommended as reference substances in the OECD TG 117 (HPLC method) and the draft OECD TG 122 (pH-metric method). Therefore, it can be expected that the logKow value recommended in these guidelines, which has a value of 1.34, has been peer-reviewed and considered as reliable. 

Consequently, a value of 1.3 is retained for log Ko/w.