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Partition coefficient

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Endpoint:
partition coefficient
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance decomposes
Endpoint:
partition coefficient
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Reference:
Composition 1
Qualifier:
no guideline followed
Principles of method if other than guideline:
estimation by calculation
GLP compliance:
no
Type of method:
other: estimation by calculation
Partition coefficient type:
octanol-water
Test material information:
Composition 1
Key result
Type:
log Pow
Partition coefficient:
2.34
Remarks on result:
other: estimated by calculation
Conclusions:
The partition coefficient of 4,4'-bi-o-toluidine (TODA) was calculated to be 2.34.
Executive summary:

The partition coefficient of 4,4'-bi-o-toluidine (TODA) was calculated to be 2.34.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2005
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Reason / purpose:
reference to other study
Related information:
Composition 1
Reason / purpose:
reference to other study
Related information:
Composition 1
Reference:
Composition 1
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
1995
Deviations:
no
GLP compliance:
not specified
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Test material information:
Composition 1
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
4.5
Temp.:
20 °C
Remarks on result:
other: no information about pH value available
Details on results:
A pH value can not be indicated, as TODI was found to be insoluble in water, but hydrolyses very fast (see: Sec.: 5.1.2: TODI: Hydrolysis as a function of pH).
Conclusions:
By applying published data of a supporting substance the log Pow of TODI can be estimated to be in a range similar to the supporting substance, because of the analogy of their molecular structures. The log Pow of the supporting substance (Methylenediphenyl diisocyanate, CAS 26447-40-5, EINECS 247-714-0) was found to be 4.5.
Executive summary:

By applying published data of a supporting substance the log Pow of TODI can be estimated to be in a range similar to the supporting substance, because of the analogy of their molecular structures. The log Pow of the supporting substance (Methylenediphenyl diisocyanate, CAS 26447-40-5, EINECS 247-714-0) was found to be 4.5 measured by HPLC, which is in quite good accordance with the calculated value of log Pow > 6.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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 adequate and reliable documentation / justification
Justification for type of information:
Please refer to the QMRF and QPRF files provided under the section attached justification.
Reference:
Composition 1
Composition 2
Composition 3
Qualifier:
according to
Guideline:
other: REACH guidance on QSAR R.6
Principles of method if other than guideline:
Estimates the log octanol-water partition coefficient, log KOW, of chemicals using an atom/fragment contribution method.
GLP compliance:
no
Type of method:
calculation method (fragments)
Partition coefficient type:
octanol-water
Test material information:
Composition 1
Specific details on test material used for the study:
SMILES: Nc(c(cc(c(ccc(N)c1C)c1)c2)C)c2
Key result
Type:
log Pow
Partition coefficient:
3.018
Temp.:
25 °C
Remarks on result:
other: QSAR predicted value. The substance is within the applicability domain of the model.

KOWWIN Program (v1.68) Results:

TYPE

 NUM

LOGKOW FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

2

-CH3 [aliphatic carbon]

0.5473

1.0946

Frag

12

Aromatic Carbon

0.2940

3.5280

Frag

2

-N   [aliphatic N, one aromatic attach]

-0.9170

-1.8340

Const

 

Equation Constant

 

0.2290

Log Kow

 

 

 

= 3.0176

 

Conclusions:
Using KOWWIN v1.68 the logPow of the test item was calculated to be 3.0176 at 25 °C. The substance is within the applicability domain of the model. In addition, the logPow value was estimated to be 2.34 (expert database match) using KOWWIN of EPI Suite.
Executive summary:

The logPow was calculated using KOWWIN v1.68 as part of EPISuite v4.11 from US Environmental Protection Agency.

Using KOWWIN v1.68 the log Kow of the test item was calculated to be 3.0176 at 25 °C (EPI Suite, 2014).

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model isapplicable to thequery chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model isrelevant for theregulatory purpose.

 

For assessment and jsutification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.

 

Description of the prediction Model

The prediction model was descripted using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 

 

Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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 adequate and reliable documentation / justification
Justification for type of information:
Please refer to the QMRF and QPRF files provided under the section attached justification.
Reference:
Composition 1
Composition 2
Composition 3
Qualifier:
according to
Guideline:
other: REACH guidance on QSAR R.6
Principles of method if other than guideline:
Estimates the log octanol-water partition coefficient, log KOW, of chemicals using an atom/fragment contribution method.
GLP compliance:
no
Type of method:
calculation method (fragments)
Partition coefficient type:
octanol-water
Test material information:
Composition 1
Specific details on test material used for the study:
SMILES: O=C=N/c1ccc(cc1C)c2ccc(\N=C=O)c(C)c2
Key result
Type:
log Pow
Partition coefficient:
6.052
Temp.:
25 °C
Remarks on result:
other: QSAE predicted value. The substance is not within the applicability domain of the model.

KOWWIN Program (v1.68) Results:

TYPE

 NUM

LOGKOW FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

2

-CH3 [aliphatic carbon]

0.5473

1.0946

Frag

12

Aromatic Carbon

0.2940

3.5280

Frag

2

-N=C=O  [isocyanate, aromatic attach]

0.6000**

1.2000

Const

 

Equation Constant

 

0.2290

Log Kow

 

 

 

= 6.0516

 

Note: An estimated coefficient (**) used.

 

Conclusions:
Using KOWWIN v1.68 the logPow of the test item was calculated to be 6.0516 at 25 °C. The substance is not within the applicability domain of the model due to fast hydrolysis of the substance. Thus the estimation may be less accurate.
Executive summary:

The logPow was calculated using KOWWIN v1.68 as part of EPISuite v4.11 from US Environmental Protection Agency.

Using KOWWIN v1.68 the log Kow of the test item was calculated to be 6.0516 at 25 °C (EPI Suite, 2014).

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model is applicable to the query chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model isrelevant for theregulatory purpose.

 

For assessment and justification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.

 

Description of the prediction Model

The prediction model was descripted using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 

 

Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.

Description of key information

The result was determined by QSAR estimation with the programme EPIWIN using KOWWIN v1.68 that is recommended in the REACH Guidance on information requirements and chemical safety assessment (2008), Chapter R.7.1.7.3, Table R.7.1-21.The log Kow of TODI was calculated to be 6.0516. Additionally, the log KOW of the degradation product TODA was calculated to be 3.0176 (KOWWIN v1.68 estimate) or 2.34 (expert database match) using KOWWIN of EPISuite.

Key value for chemical safety assessment

Log Kow (Log Pow):
6.052
at the temperature of:
25 °C

Additional information

An experimental determination of the partition coefficient of TODI is technically not feasible, because of the very fast hydrolysis of the substance (see IUCLID Section 5.1.2, Hydrolysis as a function of pH).

The result was determined by QSAR estimation with the programme EPIWIN using KOWWIN v1.68 that is recommended in the REACH Guidance on information requirements and chemical safety assessment (2008), Chapter R.7.1.7.3, Table R.7.1-21.The log Kow of TODI was calculated to be 6.0516. Additionally, the log KOW of the degradation product TODA was calculated to be 3.0176 (KOWWIN v1.68 estimate) or 2.34 (expert database match) using KOWWIN of EPISuite.

By applying published data of a supporting substance ( methylenediphenyl diisocyanate) the log Pow of TODI can be estimated to be in a range similar to the supporting substance, because of the analogy of their molecular structures. The log Pow of the supporting substance (Methylenediphenyl diisocyanate, CAS 26447-40-5, EINECS 247-714-0) was found to be 4.5 measured by HPLC, which is in quite good accordance with the calculated value. Additionally the partition coefficient of TODI's hydrolysis degradation product TODA (3,3'-Dimethylbenzidine) was reported to be 2.34.