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Partition coefficient

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Endpoint:
partition coefficient
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance decomposes
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of REACH Annex VII, the partition coefficient study does not need to be conducted as the substance is hydrolytically unstable (decompose) at pH 4, 7 and 9 (half-life less than 12 hours). The half-life of the test item in water was determined to be <1 min (reference 5.2.1-1).
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2018-05-04
Reliability:
1 (reliable without restriction)
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.
Qualifier:
according to
Guideline:
other: REACH guidance on QSAR R.6
Deviations:
no
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
Key result
Type:
log Pow
Partition coefficient:
2.6
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:

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

Log Kow(version 1.68 estimate): 2.60

 

SMILES : O(C(OCC)(OCC)C)CC

CHEM  : Ethane, 1,1,1-triethoxy-

MOL FOR: C8 H18 O3

MOL WT : 162.23

TYPE NUM LOGKOW FRAGMENT DESCRIPTION COEFF VALUE
Frag 4  -CH3 [aliphatic carbon] 0.5473 2.1892
Frag 3  -CH2- [aliphatic carbon] 0.4911 1.4733
Frag 1  C [aliphatic carbon - No H, not tert] 0.9723 0.9723
Frag 3  -O- [oxygen, aliphatic attach]  -1.2566  -3.7698
Factor 3 C-O-C-O-C structure correction 0.5036 1.5108
Const   Equation Constant   0.2290

Log Kow = 2.6048

Conclusions:
Using KOWWIN v1.68 the logPow of the test item was calculated to be 2.60 at 25 °C. The substance is within the applicability domain of the model. Thus, the estimation can be considered accurate.
Executive summary:

The log Pow 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 2.60 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 is relevant for the regulatory 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

In accordance with column 2 of REACH Annex VII, the partition coefficient study does not need to be conducted as the substance is hydrolytically unstable (decompose) at pH 4, 7 and 9 (half-life less than 12 hours). The half-life of the test item in water was determined to be <1 min (see references 5.2.1-1 and 4.7-2).

However, using KOWWIN v1.68 with the EPISuite Software v4.11 the log Pow of the test item was determined to be 2.60 at 25 °C.

In addition the logPow of the hydrolysis products was reported by Hansch, C et al (1995) to be 0.68 for ethyl acetat and -0.35 for ethanol. Thus, the QSAR estimation for the parent compound can be regarded as worst case assumption.

Key value for chemical safety assessment

Log Kow (Log Pow):
2.6
at the temperature of:
20 °C

Additional information

QSAR calculation (reference 4.7-1)

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 2.60 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 is relevant for the regulatory 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.