Registration Dossier

Diss Factsheets

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
partition coefficient
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance has a high surface activity
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source
Remarks:
The partition coefficient of the major constituent of the substance was estimated with a QSAR-based tool that is well recognised and accepted by European authorities.
Justification for type of information:
1. SOFTWARE
US EPA Episuite modelling tool box (version 4.1)

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

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
(confidential)
Principles of method if other than guideline:
QSAR modelling
Type of method:
calculation method (fragments)
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
3.67
Temp.:
25 °C
pH:
ca. 0 - ca. 14
Conclusions:
The substance has low potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow <4).
Executive summary:

The partition coefficient of the substance was modelled with the KOWWIN estimation tool, version 1.68, which is part of the US EPA Episuite modelling tool box (version 4.1).

The substance was characterised with a SMILES code, representing a substance with a side chain containing 13 Carbon atoms. The predicted log Kow at 25 °C was 3.67.

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 (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source
Remarks:
The partition coefficient of the transformation product of the major constituent of the substance was estimated with a QSAR-based tool that is well recognised and accepted by European authorities.
Justification for type of information:
1. SOFTWARE
US EPA Episuite modelling tool box (version 4.1)

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

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
(confidential)
Principles of method if other than guideline:
QSAR modelling
Type of method:
calculation method (fragments)
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
4.94
Temp.:
25 °C
pH:
ca. 0 - ca. 14
Remarks on result:
other:
Remarks:
C13-1EO
Type:
log Pow
Partition coefficient:
4.45
Remarks on result:
other:
Remarks:
C12-1EO
Executive summary:

The partition coefficient of the transformation product was modelled with the KOWWIN estimation tool, version 1.68, which is part of the US EPA Episuite modelling tool box (version 4.1).

The substance was characterised with a SMILES code, representing a substance with a side chain containing 13 or 12 Carbon atoms. The predicted log Kow at 25 °C was 4.94, and 4.45 respectively.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Qualifier:
according to guideline
Guideline:
OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)
Type of method:
slow-stirring method
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
4.47
pH:
2
Type:
log Pow
Partition coefficient:
3.15
pH:
7
Type:
log Pow
Partition coefficient:
1.47
pH:
9

For comparison, KOWWIN predicted log Kow value for the non-ionised form is logKow=5.00

Executive summary:

The publication reports the partition coefficient measured with the slow-stirring method, as a function of the pH.

It ranges from 4.47 for the non-ionised lauric acid, down to 1.47 for the carboxylate form.

Description of key information

Surface-active.

QSAR estimated Log Kow ca 3.67 for a representative structure of the major constituent.

Transformation products are anticipated to have logKow in the range 4 - 5.

Key value for chemical safety assessment

Log Kow (Log Pow):
4.5
at the temperature of:
25 °C

Additional information

The experimental study was not relevant, considering the high surface activity of the substance.

Therefore, a QSAR-calculated value is provided for the major constituent (C13 -1EO) instead.

As supporting information, the same model provides an estimation of 4.94 for the corresponding transformation product, as a worst-case value refering to the non-ionised form. With a pKa expected ca 4.95 (please refer to IU section 4.21), unless very acidic conditions (pH<3), the carboxylate form should be present, and expected to have a lower logKow (ionised form are more soluble).

Also, a recent publication provides logKow for the non-ethoxylated C12 carboxylate, measured with the slow-stirring method. Values range between 4.47 and 1.47, for the non- and fully-ionised forms respectively. The corresponding QSAR prediction is 5.00, suggesting that the model may overestimates the logKow.

A calculated value of 4.45 for the C12-1EO is consistent with the trend that ethoxylates are more soluble, i.e. have lower logKow.

 Substance  QSAR (KowWin) prediction  Experimental data (slow-stir)
 amide C13 -1EO  3.67  n/a
 acid C13 -1EO  4.94  n/a
 acid C12 -1EO  4.45  n/a
 acid C12  5.00  4.47

The conclusion is that neither the parent amides, nor the corresponding transformation products, as ethoxylated and partially ionised in actual conditions, are anticipated to fall above the threshold of 5, but are likely to be over the CLP aquatic chronic toxicity cut-off value of 4.

For purpose of CSA, as a worst-case compared to the parent constituent, the mid-range value for the transformation products will be used.