Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
June 16- June 25, 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed in laboratory certified to be compliant with GLP.
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Qualifier:
according to guideline
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Deviations:
yes
Remarks:
The partition coefficient is determinated in dependance with pH.
Qualifier:
according to guideline
Guideline:
EPA OPPTS 830.7550 (Partition Coefficient, n-octanol / H2O, Shake Flask Method)
GLP compliance:
no
Remarks:
in laboratory certified to be compliant with GLP
Type of method:
shake-flask method to: flask method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
-1.5
Temp.:
25 °C
pH:
5
Type:
log Pow
Partition coefficient:
-2.8
Temp.:
25 °C
pH:
6.7
Type:
log Pow
Partition coefficient:
< -3.7
Temp.:
25 °C
pH:
8.8
Remarks on result:
other: At the pH value of 8.8 the octanol / water partition coefficient could not be determined experimentally because the levels of the substance in the octanol phase were below the limit of detection.
Details on results:
The substance is an acid and, consequently, the level of the protonated form of it increases with increasing pH value, therefore the relative concentration of the substance in the octanol phases would be expected to decrease with increasing pH value.
At final pH values of 5.0 and 6.7 log Pow values of -1.5 and -2.8 respectively were determined for the substance.
At the equilibrium pH values of 8.8 the octanol / water partition coefficient could not be determined experimentally because the levels of the substance in the octanol phase were below the limit of detection. At pH values greater than pH 6.7 log Pow will be expected from theory to be less than - 2.8 and this has indeed been shown by experiment to be so.
Conclusions:
This study is considered to be adequate and reliable.

Description of key information

-1.5, pH=5.0, 25°C shake-flash method, Halarnakar, 2010
-2.8, pH=6.7, 25°C shake-flash method, Halarnakar, 2010
<-3.7, pH=8.8, 25°C shake-flash method, Halarnakar, 2010

- At the equilibrium pH values of 8.8 the octanol / water partition coefficient could not be determined experimentally because the levels of the substance in the octanol phase were below the limit of detection.

Key value for chemical safety assessment

Log Kow (Log Pow):
-2.8
at the temperature of:
25 °C

Additional information

The key study has been performed under OECD and EU Guidelines therefore it is considered reliable and adequate for classification and labeling, and risk assessment purposes.

The two literature values available are considered disregarded. The same group of authors published three QSAR models, i.e. Liao et al 1996 and Chen at al 1996 & 1997. However the log Kow in the first submission is reported to be 0.10 for 4.6-dihydroxypyrimidin, the second submission reports the value 1.49. Nonetheless the third submission refers again to the value 0.10. In the light of this interplay the scientific accurateness of the data handling must be disbelieved.