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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
15 February 2018
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:
1. SOFTWARE
Estimation Programme Interface (EPI) Suite programme for Microsoft Windows v4.11.


2. MODEL (incl. version number)
KOCWIN v2.00


3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: CCCCNCCCC


4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please refer to attached justification.


5. APPLICABILITY DOMAIN
Please refer to attached justification.


6. ADEQUACY OF THE RESULT
Please refer to attached justification.
Guideline:
other: ECHA's Guidance on information requirements and chemical safety assessment Chapter R.6: QSARs and grouping of chemicals
Version / remarks:
May 2008
Principles of method if other than guideline:
- Software tool(s) used including version:
Estimation Programme Interface (EPI) Suite programme for Microsoft Windows v4.11.


- Model(s) used:
KOCWIN v2.00
Specific details on test material used for the study:
SMILES notation: CCCCNCCCC
Key result
Type:
log Koc
Value:
2.43 dimensionless
Remarks on result:
other: QSAR predicted value
Remarks:
Dibutylamine esult derived using Kow method
Type:
log Koc
Value:
2.475 dimensionless
Remarks on result:
other: QSAR predicted value
Remarks:
Dibutylamine result derived using MCI method

Constituent

Estimated log10Koc

MCI method

Kowmethod

N,N,N',N'-tetrabutylmethylenediamine

4.1600

3.9472

dibutylamine

2.4755

2.4303

KOCWIN is not underpinned by chemical or biological mechanisms. The model uses two separate methodologies, Molecular Connectivity Index (MCI) and Log Kow methodology.

MCI methodology:

Two separate linear regressions were performed. The first regression related log Koc of non-polar compounds to the first-order MCI in the absence of correction factors. The second regression related log Koc of polar compounds and included correction factors. The regression coefficients were derived via multiple linear regression of the correction descriptors to the residual error of the prediction from the non-polar equation.

Log Kow methodology:

Separate equations correlating log Koc with log Kow were derived for nonpolar and polar compounds, as with the MCI methodology a set of regressions were performed for non-polar and polar compounds. Effectively, the log Kow methodology replaces the MCI descriptor with log Kow and derives similar equations.  

Applicability Domain:

Both the MCI and Log Kow methodologies have a low degree of error within the limits of the training set when you examine the coefficient of determination and the standard deviation.  Both N,N,N',N'-tetrabutylmethylenediamine and dibutylamine fall within of the domain of the training set.  

As such the results of these estimations can be considered to be reliable given the limits of the test set.

Conclusions:
The adsorption/desorption coefficient (Log Koc) of the constituent dibutylamine was estimated to be 2.4303 (Log Kow method).
Executive summary:

QSAR Prediction. – The adsorption/desorption coefficient of the test item constituent dibutylamine was predicted using KOCWIN v2.00; integrated within the Estimation Programme Interface (EPI) Suite programme for Microsoft Windows v4.11.  In accordance with ECHA’s Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint Specific Guidance (Version 6.0 – July 2017), Section R.7.1.15.4, it is suitable to use an QSAR value to fulfil this endpoint under certain circumstances.

Two predictions were performed using the Log Kow method and the MCI method.  In both instances the constituent dibutylamine was within the molecular weight domain of the models training set, furthermore surface activity was ruled out following structural assessment.  The accuracy of the prediction was refined using predicted Log Kow values derived using iSafeRat® – Version 1.8.

The adsorption/desorption coefficient of the test item constituent dibutylamine was estimated to be 2.4303 (Log Kow method).

Description of key information

Adsorption/desorption coefficient: Constituent 2 (dibutylamine) = 2.4303 (EPI Suite, KOCWIN v2.00, Log Kow method); ECHA's Guidance on information requirements and chemical safety assessment Chapter R.6: QSARs and grouping of chemicals - May 2008, (2018)

Key value for chemical safety assessment

Koc at 20 °C:
2.43

Additional information

QSAR Predictions – The adsorption/desorption coefficient of the test item constituents N,N,N',N'-tetrabutylmethylenediamine and dibutylamine were predicted using KOCWIN v2.00; integrated within the Estimation Programme Interface (EPI) Suite programme for Microsoft Windows v4.11.  In accordance with ECHA’s Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint Specific Guidance (Version 6.0 – July 2017), Section R.7.1.15.4, it is suitable to use an QSAR value to fulfil this endpoint under certain circumstances.

Two predictions were performed on each constituent using the Log Kowmethod and the MCI method.  In all instances the constituents were within the molecular weight domain of the models training set, furthermore surface activity was ruled out following structural assessment.  The accuracy of the prediction was refined using predicted Log Kowvalues derived using iSafeRat® – Version 1.8.

The adsorption/desorption coefficient of the test item constituents were estimated to be:

  • N,N,N',N'-tetrabutylmethylenediamine = 3.9472 (Log Kowmethod)
  • dibutylamine = 2.4303 (Log Kowmethod)

[LogKoc: 0.386]