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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
OECD 105 Guideline study without GLP auditing. The conclusion states that there were no observations arousing doubts concerning the accuracy of the results and the validity of the study.
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
GLP compliance:
no
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
> 6.2
Temp.:
25 °C
pH:
> 4 - < 7
Remarks on result:
other:
Remarks:
pH not reported in this study
Key result
Type:
log Pow
Partition coefficient:
< 0.3
Temp.:
25 °C
pH:
> 4 - < 7
Remarks on result:
other:
Remarks:
pH not reported in this study
Details on results:
The test substance eluted primarily in 8 peaks, but the preponderance of material is found in the peaks 1 and 8. Due to the fact that the retention time of peak 1 lay below the retention time of thiourea (log POW is not calculable) the log POW of this peak is stated as < 0.3 (log POW of 2-Butanone). The calculation of the log POW of the peak 8 is not possible, because this peak eluted not in the isocratic part of the HPLC program. Because the retention time of the test substance peak is higher than the retention time of DDT (35.2 minutes) the log POW of peak 8 is stated as > 6.2 (log POW of DDT). The log POW of ZWA 5496/100 is stated as log POW < 0.3 to > 6.2.
Conclusions:
The log Pow for the test substance is > 6.22, in a study using the OECD 117 (HPLC) method. The test material eluted after the highest elution standard, DDT, so the log Pow is concluded to be higher than this standard.
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
April 2017
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
Justification for type of information:
Estimated data are obtained from a reliable (Q)SAR program developed and validated by the United States Environmental Protection Agency (U.S. EPA).
Qualifier:
no guideline required
Principles of method if other than guideline:
Estimated data are obtained from a reliable (Q)SAR program developed and validated by the United States Environmental Protection Agency (U.S. EPA). This program is included in the OECD (Q)SAR Toolbox for use in filling REACH data gaps.
GLP compliance:
no
Type of method:
other: QSAR
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Theoretical ester which represents a structural analogue and having characteristics which meet criteria of the applicability domain.
O=C(OCCCCCC)CCCCCCCC(C(C(=O)(OC))CC(=O)(OC))C=CC=CCC=CCC

The structure is a succinyl-modified apha-linolenic acid derived from saponified Linseed oil, which contains a terminal free acid moiety esterified with a hexyl-group to mimic the triglyceride, and which also contains a side-chain methyl ester to remove issues associated with ionization of an acid group. These modifications allow the theoretical structure to stay within the applicability domain of the model, but retain the properties of the registered substance.

Analytical method:
other: KOWWIN (v1.68)
Key result
Type:
log Pow
Partition coefficient:
9.96
Temp.:
25 °C
pH:
> 4 - <= 7
Remarks on result:
other: limits of QSAR Prediction report
Remarks:
The pH was not given in the QSAR Prediction report
Details on results:
Structure Octanol-water partition coefficient (Kow) Log Kow (est) Wat Sol, mg/L Koc, L/kg Log Koc
1 2.20E+07 6.343 2.58E-02 8.57E+04 4.933
2 4.68E+09 9.67 1.02E-04 1.66E+05 5.22
3 9.12E+09 9.96 2.03E-06 1.33E+07 7.1251

KOWWIN Program (v1.68) Results:

===============================

Log Kow(version 1.68 estimate): 9.96

SMILES : O=C(OCCCCCC)CCCCCCCC(C(C(=O)(OC))CC(=O)(OC))C=CC=CCC=CCC

CHEM   :

MOL FOR: C30 H50 O6

MOL WT : 506.73

-------+-----+--------------------------------------------+---------+--------

TYPE  | NUM |        LOGKOW FRAGMENT DESCRIPTION         |  COEFF  |  VALUE

-------+-----+--------------------------------------------+---------+--------

Frag  |  4  |  -CH3    [aliphatic carbon]                | 0.5473  |  2.1892

Frag  | 15  |  -CH2-   [aliphatic carbon]                | 0.4911  |  7.3665

Frag  |  2  |  -CH     [aliphatic carbon]                | 0.3614  |  0.7228

Frag  |  6  |  =CH- or =C<  [olefinc carbon]             | 0.3836  |  2.3016

Frag  |  3  |  -C(=O)O  [ester, aliphatic attach]        |-0.9505  | -2.8515

Const |     |  Equation Constant                               |         |  0.2290

-------+-----+--------------------------------------------+---------+--------

                                                        Log Kow   =   9.9576

Conclusions:
The estimated log Kow value of a theoretical representative structure with characteristics of the UVCB substance is 9.96.

Description of key information

Log Kow = 9.96 (est.)

Key value for chemical safety assessment

Log Kow (Log Pow):
9.96
at the temperature of:
25 °C

Additional information

Testing of the UVCB test substance for the log Kow endpoint determined to be technically infeasible. The constituents of the complex UVCB test substance are diverse, and unable to be easily modeled. A representative ester was devised which represents a "worst case" for exposure. The behaviour of this representative ester for solubility in water, log Kow and log Koc was examined using EPI-Suite models. The log Kow was determined to be 9.96.