Prop-2-yn-1-yl 1H-imidazole-1-carboxylate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

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:

1. SOFTWARE
EPI Suite 4.1

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

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: C#CCOC(=O)N1C=CN=C1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
[[Explain how the model fulfils the OECD principles for (Q)SAR model validation. Consider attaching the QMRF and/or QPRF or providing a link]
- Defined endpoint: Soil adsorption coeffiecient (Koc)

- Unambiguous algorithm: Please see attachment "EPI Suite_KOCWIN_Algorithm.pdf"

- Defined domain of applicability:
The minimum molecular weight of Training Set is 32.04, maximum 665.02.
The minimum molecular weight of Validation is 73.14, maximum 504.12.

- Appropriate measures of goodness-of-fit and robustness and predictivity: Please see attachment "EPI Suite_KOCWIN_Accuracy.pdf"

- Mechanistic interpretation:
The first-order molecular connectivity index (MCI) has been successfully used to predict soil sorption coefficients (Koc) for nonpolar organics, but extension of the model to polar compounds has been problematic.  To address this, we developed a new estimation method based on MCI and series of statistically derived fragment contribution factors for polar compounds. After developing an extensive database of measured Koc values, we divided the dataset into a training set of 189 chemicals and an independent validation set of 205 chemicals.  Two linear regressions were then performed.  First, measured log Koc values for nonpolar compounds in the training set were correlated with MCI.  
The second regression was developed by using the deviations between measured log Koc and the log Koc estimated with the nonpolar equation and the number of certain structural fragments in the polar compounds.  The final equation for predicting log Koc accounts for 96% and 86% of the variation in the measured values for the training and validation sets, respectively.  Results also show that the model outperforms and covers a wider range of chemical structures than do models based on octanol-water partition coefficients (Kow) or water solubility.

5. APPLICABILITY DOMAIN
[Explain how the substance falls within the applicability domain of the model]
- Descriptor domain:
The molecular weight of target chemical is 150.14, which falls within the applicability domain.

- Structural domain: N/A
- Mechanistic domain: N/A
- Similarity with analogues in the training set: N/A
- Other considerations (as appropriate): N/A

6. ADEQUACY OF THE RESULT
[Explain how the prediction fits the purpose of classification and labelling and/or risk assessment]
Reliable predicted value obtained by EPI Suite 4.1 using KOCWIN v2.00. The pridiction fulfilling the OECD five criteria for validation of QSAR models.

Principles of method if other than guideline:

- Software tool(s) used including version: EPI Suite 4.1
- Model(s) used: KOCWIN v2.00
- Model description: Please see attachment "EPI Suite_KOCWIN_Algorithm.pdf"
- Justification of QSAR prediction: Reliable predicted value obtained by EPI Suite 4.1 using KOCWIN v2.00. The pridiction fulfilling the OECD five criteria for validation of QSAR models.

Key result

Type:

Koc

Value:

ca. 15.27 L/kg

Remarks on result:

not measured/tested

Remarks:

Koc Estimate from MCI

Key result

Type:

Koc

Value:

ca. 34.41 L/kg

Remarks on result:

not measured/tested

Remarks:

Koc Estimate from Log Kow.

Conclusions:

The estimated Koc from MCI is 15.27 L/kg.
The estimated Koc from Log Kow is 34.41 L/kg.

Executive summary:

Reliable predicted value obtained by EPI Suite 4.1 using KOCWIN v2.00. The pridiction fulfilling the OECD five criteria for validation of QSAR models.

The estimated Koc from MCI is 15.27 L/kg. The estimated Koc from Log Kow is 34.41 L/kg.

Description of key information

The KOC results estimated by the MCI method and the KOW method are 15.27 L/kg and 34.41 L/kg, respectively. The lowest value is 15.27 L/kg.

Key value for chemical safety assessment

Koc at 20 °C:

15.27