butanedioic acid, 2-octenyl

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017

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:

1. SOFTWARE:
The n-octanol/water partition coefficient of octenylsuccinic acid was estimated in this work using quantitative structure-activity relationship (QSAR) model (KOWWIN v1.68, US Environmental Protection Agency, 2010). KOWWIN was chosen due to its estimation accuracy and the transparency of the model and training set.
The compound for which KOW was estimated (i.e., target compound) was octenylsuccinic acid with a molecular weight of 228 g/mol.

2. MODEL (incl. version number): Quantitative structure-activity relationship (QSAR) model (KOWWIN v1.68, US Environmental Protection Agency, 2010)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL:
Octenylsuccinic acid: O=C(O)C(CC(=O)O)CC=CCCCCC

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL:
Endpoint (OECD Principle 1):
a. Endpoint: n-octanol/water partition coefficient (POW or KOW)
b. Dependent variable: Log KOW or Log POW

Algorithm (OECD Principle 2):
a. Model or submodel name: KOWWIN for n-octanol/water partition coefficient
b. Model version: v1.68, U.S. EPA, 2010
c. Reference to QMRF: N/A
d. Predicted value (model result): 2.8860
e. Predicted value (comments):The corresponding n-octanol/water partition coefficient (Log KOW) for octenylsuccinic acid is 2.89.
f. Input for prediction: SMILES codes
i. Octenylsuccinic acid: O=C(O)C(CC(=O)O)CC=CCCCCC
g. Descriptor values: N/A

5. APPLICABILITY DOMAIN:
Applicability domain (OECD principle 3):
a. Domains:
i. Descriptor domain: N/A
ii. Structural fragment domain: in domain
KOWWIN uses a “fragment constant” methodology to predict Log KOW. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the Log KOW estimate. The target compound is within the domain of KOWWIN (v1.68). The functional groups or other structural features of the target compound are all represented in the training set.
iii. Mechanism domain: in domain.
KOWWIN model is developed based on the assumption that the phase transfer enthalpy of a molecule (for hydrophobic molecules this is largely the negative of the solvation enthalpy) is the sum of the phase transfer enthalpies of its fragments. The enthalpy for a list of fragments is estimated from a database of n-octanol/water partitioning coefficient for molecules containing these fragments. Predictions can be made for molecules that contain these fragments. The approach is described in more details by Meylan and Howard (1995) for deriving n-octanol/water partitioning fragment contribution. The target compound is within the domain of KOWWIN (v1.68).
iv. Metabolic domain: not relevant
b. Structural analogues: The training dataset and the validation dataset have been searched for analogues using a sub-structural search for relevant fragments present in the target compound. The substructure that was searched is carboxylic acid. Examples of structural analogues are evaluated for the model performance. A comparison of the experimental and predicted values is shown in Table 1.
c. Considerations on structural analogues:
Estimated Log KOW values for the analogues using KOWWIN are consistent with the experimental data. As the prediction is based on the contribution of the structural fragments, the prediction for the target compound is considered reliable.

The uncertainty of the prediction (OECD principle 4):
The predications are considered reliable because the estimated log KOW values for the analogues are consistent with the experimental data. In addition, KOWWIN is considered reliable within the domain based on the correlation between the
experimental and KOWWIN estimated Log KOW values presented by the developers (See below).
Statistics Training Set Validation Set
Number of compounds in dataset 2447 10946
Correlation coeff (R2) 0.982 0.943
Standard deviation 0.217 0.479
Absolute deviation 0.159 0.356

The chemical and biological mechanisms according to the model underpinning the predicted result (OECD principle 5):
The KOWWIN model estimates Log KOW based on the assumption that the phase transfer enthalpy of a molecule (for hydrophobic molecules this is largely the negative of the solvation enthalpy) is the sum of the phase transfer enthalpies of
its fragments. The enthalpy for a list of fragments is estimated from a database of n-octanol/water partitioning coefficient for molecules containing these fragments. Predictions can be made for molecules that contain these fragments. The
approach is described in more details by Meylan and Howard (1995) for deriving n-octanol/water partitioning fragment contribution.

6. ADEQUACY OF THE RESULT
The n-octanol/water partition coefficient of octenylsuccinic acid was estimated in this work using quantitative structure-activity relationship (QSAR) model (KOWWIN v1.68, US Environmental Protection Agency, 2010). KOWWIN was chosen due to its estimation accuracy and the transparency of the model and training set.

Guideline:

other: QSAR Prediction Reporting Format (QPRF) v 1.1

Principles of method if other than guideline:

1. SOFTWARE:
The n-octanol/water partition coefficient of octenylsuccinic acid was estimated in this work using quantitative structure-activity relationship (QSAR) model (KOWWIN v1.68, US Environmental Protection Agency, 2010). KOWWIN was chosen due to its estimation accuracy and the transparency of the model and training set.
The compound for which KOW was estimated (i.e., target compound) was octenylsuccinic acid with a molecular weight of 228 g/mol.

2. MODEL (incl. version number): Quantitative structure-activity relationship (QSAR) model (KOWWIN v1.68, US Environmental Protection Agency, 2010)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL:
Octenylsuccinic acid: O=C(O)C(CC(=O)O)CC=CCCCCC

The n-octanol/water partition coefficient of octenylsuccinic acid was estimated in this work using quantitative structure-activity relationship (QSAR) model (KOWWIN v1.68, US Environmental Protection Agency, 2010). KOWWIN was chosen due to its estimation accuracy and the transparency of the model and training set.

GLP compliance:

no

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

Input for prediction: SMILES codes
i. Octenylsuccinic acid: O=C(O)C(CC(=O)O)CC=CCCCCC

Key result

Type:

log Pow

Partition coefficient:

2.89

Remarks on result:

other: QSAR

Details on results:

The estimated Log KOW value for octenylsuccinic acid was 2.89.

Conclusions:

The estimated Log KOW value for octenylsuccinic acid was 2.89. The estimation by KOWWIN is deemed reliable with high confidence because octenylsuccinic acid is within the estimation domain of the model, and estimated Log KOW values of structural analogues of octenylsuccinic acid agree well with existing experimental data.

Executive summary:

The n-octanol/water partition coefficient (POW or KOW) of octenylsuccinic acid (CAS Registry Number: 62568-82-5) was estimated using quantitative structure-activity relationship (QSAR). The compound for which KOW was estimated was octenylsuccinic acid with a molecular weight of 228 g/mol. The logarithm of KOW (Log KOW or Log POW) was calculated for octenylsuccinic acid using QSAR model KOWWIN (v1.68, U.S. EPA 2010) which uses a “fragment constant” methodology to predict Log KOW. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the Log KOW estimate. KOWWIN was chosen due to its estimation accuracy and

its transparency of the model and training set. Simplified molecular input line entry system (SMILES) code for octenylsuccinic acid was used as the input for the KOWWIN model.

The estimated Log KOW value for octenylsuccinic acid was 2.89. The estimation by KOWWIN is deemed reliable with high confidence because octenylsuccinic acid is within the estimation domain of the model, and estimated Log KOW values of structural analogues of octenylsuccinic acid agree well with existing experimental data.

Description of key information

The estimated Log KOW value for octenylsuccinic acid was 2.89. The estimation by KOWWIN is deemed reliable with high confidence because octenylsuccinic acid is within the estimation domain of the model, and estimated Log KOW values of structural analogues of octenylsuccinic acid agree well with existing experimental data.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.89