2,2-dimethylpropane-1,3-diyl dibenzoate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method.

Justification for type of information:

1. SOFTWARE
Individual model KOCWIN included in the Estimation Programs Interface (EPI) Suite.

2. MODEL (incl. version number)
KOCWIN v2.00 included in EPI Suite v 4.11, 2000-2012.

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
The CAS Number was entered in the initial data entry screen. In the structure window, the molecular weight, structural formula and the structure of the input SMILES notation is shown.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
a. Defined endpoint:
Organic carbon partition coefficient, given as log Koc.
b. Dependent variable:
KOCWIN estimates log Koc with two separate estimation methodologies:
(1) Estimation using first order Molecular Connecitivity Index (MCI) and
(2) Estimation using log Kow (octanol-water partition coefficient)
c. Algorithm:
Log Koc according to MCI method is calculated using the formula:
log Koc = 0.5213 MCI + 0.60 + ΣPfN
Log Koc according to the log Kow method is calculated using the formula:
log Koc = 0.55313 log Kow + 0.9251 + ΣPfN
(ΣPfN is the sum of all relevant correction factor coefficients multiplied by the number (N) of that factor in each chemical structure)
d. Descriptor values:
Log Kow method:
For estimation of log Koc of 2,2-dimethylpropane-1,3-diyl dibenzoate according to log Kow method an experimentally determined log Kow of 4.7 was used (see Study report 2014/0013/04).
MCI method:
For log Koc estimation of 2,2-dimethylpropane-1,3-diyl dibenzoate according to MCI method the following fragment descriptors were applied:
Type: Fragment correction
No. of Fragments: 2
Fragment: (-C-CO-O-C-) or (HCO-O-C)
e. Applicability domain:
The minimum and maximum values for molecular weight are the following:
(1) Training set molecular weights: 32.04-665.02 g/mol and
(2) Validation set molecular weights: 27.03-991.15 g/mol
f. Statistics for goodness-of-fit:
Statistical accuracy of MCI methodology for training and validation set:
i. Training without corrections:
Number: 69
R^2 correction coefficient: 0.967
Standard deviation (log Koc): 0.247
Average deviation (log Koc): 0.199
ii. Training with corrections:
Number: 447
R^2 correction coefficient: 0.900
Standard deviation (log Koc): 0.340
Average deviation (log Koc): 0.273
iii. Validation data set:
Number: 158
R^2 correction coefficient: 0.850
Standard deviation (log Koc): 0.583
Average deviation (log Koc): 0.459
Statistical accuracy of Log Koc methodology:
i. Training without corrections:
Number: 68
R^2 correction coefficient: 0.877
Standard deviation: 0.478
Average deviation: 0.371
ii. Training with corrections:
Number: 447
R^2 correction coefficient: 0.855
Standard deviation (log Koc): 0.396
Average deviation (log Koc): 0.307
iii. Validation data set:
Number: 150
R^2 correction coefficient: 0.778
Standard deviation (log Koc): 0.679
Average deviation (log Koc): 0.494
g. Mechanistic interpretation:
Log Koc is estimated based on the likeliness of a substance for sorption to surfaces of soil/sediment particles. This characteristic is triggered by lipophilic character of substances but may be modified by certain molecular fragments that need to be considered by application of correction factors. The Log Koc is a physical inherent property used extensively to describe a chemical’s likeliness to adsorb to organic carbon.
h. The uncertainty of the prediction:
2,2-dimethylpropane-1,3-diyl dibenzoate is not highly complex and the rules applied for the substance appear appropriate. An individual uncertainty for the investigated substance is not available.

5. APPLICABILITY DOMAIN
a. Domains:
i. Molecular weights:
With a molecular weight of 312.37 g/mole 2,2-dimethylpropane-1,3-diyl dibenzoate is within the range of the training set (32 665 g/mole) as well as in the range of the validation set (27 - 991 g/mole ).
ii. Structural fragment domain:
Regarding the structure of 2,2-dimethylpropane-1,3-diyl dibenzoate, the fragment descriptors found by the program are complete and listed in Appendix D (KOCWIN Fragment and Correction Factor descriptors).
iii. Mechanism domain:
No information available.
iv. Metabolic domain, if relevant:
Not relevant.
b. Structural analogues:
No information available
c. Considerations on structural analogues:
No information available

6. ADEQUACY OF THE RESULT
a. Regulatory purpose:
The data may be used under any regulatory purpose.
b. Approach for regulatory interpretation of the model result:
If no experimental data are available, the estimated result may be used to fill data gaps needed for hazard and risk assessment, classification and labelling and PBT / vPvB assessment. Further the result may be used for other calculations.
c. Outcome:
The prediction of organic carbon partition coefficient yields a useful result for further evaluation.
d. Conclusion:
The result is considered as useful for regulatory purposes.

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Principles of method if other than guideline:

Estimation Program Interface (EPI) Suite version 4.11: KOCWIN (v2.00) for the estimation of the organic carbon-normalized sorption coefficient for soil and sediment (Koc).
The Estimation Program Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics, and Syracuse Research Corporation (SRC). © 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).

GLP compliance:

no

Type of method:

other: Estimation

Media:

soil

Specific details on test material used for the study:

SMILES: O=C(OCC(C)(C)COC(=O)c(cccc1)c1)c(cccc2)c2
(values relate to the pure substance)
molecular weight: 312.37 g/mole
An experimental log Kow of 4.7 was used for calculation.

Radiolabelling:

no

Type:

log Koc

Value:

3.394

Remarks on result:

other: calculation (log Kow method)

Type:

log Koc

Value:

3.729

Remarks on result:

other: calculation (MCI method)

Phase system:

other: Koc

Type:

other: Koc

Value:

2 475 L/kg

Remarks on result:

other: calculation (log Kow method)

Phase system:

other: Koc

Type:

other: Koc

Value:

5 354 L/kg

Remarks on result:

other: calculation (MCI method)

Validity of the model:

1. Defined Endpoint: Organic carbon partition coefficient, given as logarithmic Koc and Koc

2. Unambigous algorithm: The molecule is first classified as a polar substance. Based on structure of the molecule, the following fragments were applied: 2 (-C-CO-O-C-) or (HCO-O-C). The number of times of the fragments that occurs in the structure of the substance applied by the program is verified. For estimation of logKoc according to the logKow method the experimentally determined logKow of 4.7 was used.

3. Applicable domain: With a molecular weight of 312.37 g/mole the substance is within the range of the training set (32 - 665 g/mole) as well as in the validation set (27 - 991 g/mole). Regarding the structure of 2,2-Dimethylpropan-1,3-diyldibenzoat, the fragment descriptors found by the program are complete.

4a. Statistical characteristics (MCI method): N training set without corrections = 69; N training set with correction = 447; N validation set = 158; Correction coefficient of the total training set without corrections r² = 0.967; Correlation coefficient of the total training set with corrections r² = 0.900; Correlation coefficient of the total validation set r² = 0.850.

4b. Statistical characteristics (Kow method): N training set without corrections = 68; N training set with correction = 447; N validation set = 150; Correction coefficient of the total training set without corrections r² = 0.877; Correlation coefficient of the total training set with corrections r² = 0.855; Correlation coefficient of the total validation set r² = 0.778.

5. Mechanistic interpretation: Log Koc is estimated based on the likeliness of a substance for sorption to surfaces of soil/sediment particles. The log Koc is a physical inherent property used extensively to describe a chemical's likeliness to adsob to organic carbon. Adequacy of prediction:

The result for 2,2-Dimethylpropan-1,3-diyldibenzoat falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate.

Validity of the model:

1. Defined Endpoint:

Organic carbon partition coefficient, given as logarithmic Koc and Koc

2. Unambigous algorithm:

2,2-Dimethylpropane-1,3-diyl dibenzoate is first classified as a polar substance. Based on structure of 2,2-dimethylpropane-1,3-diyl dibenzoate, the following fragments were applied: 2 (-C-CO-O-C-) or (HCO-O-C). The number of times of the fragments that occurs in the structure of 2,2-dimethylpropane-1,3-diyl dibenzoate applied by the program is verified. For estimation of logKoc according to the log Kow method the experimentally determined log Kow of 4.7 was used.

3. Applicable domain:

With a molecular weight of 312.37 g/mole 2,2-dimethylpropane-1,3-diyl dibenzoate is within the range of the training set (32 - 665 g/mole) as well as in the validation set (27 - 991 g/mole). Regarding the structure of 2,2-dimethylpropane-1,3-diyl dibenzoate, the fragment descriptors found by the program are complete.

4a. Statistical characteristics (MCI method):

N training set without corrections = 69; N training set with correction = 447; N validation set = 158; Correction coefficient of the total training set without corrections r² = 0.967; Correlation coefficient of the total training set with corrections r² = 0.900; Correlation coefficient of the total validation set r² = 0.850.

4b. Statistical characteristics (Kow method):

N training set without corrections = 68; N training set with correction = 447; N validation set = 150; Correction coefficient of the total training set without corrections r² = 0.877; Correlation coefficient of the total training set with corrections r² = 0.855; Correlation coefficient of the total validation set r² = 0.778.

5. Mechanistic interpretation:

Log Koc is estimated based on the likeliness of a substance for sorption to surfaces of soil/sediment particles. The log Koc is a physical inherent property used extensively to describe a chemical's likeliness to adsob to organic carbon.

6. Adequacy of prediction:

The result for 2,2-dimethylpropane-1,3-diyl dibenzoate falls within the applicability domain described above and the applied estimation rules appear appropriate.

Validity criteria fulfilled:

not applicable

Conclusions:

The QSAR determination of the carbon partition coefficient for 2,2-dimethylpropan-1,3-diyl dibenzoate using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed values of 2475 L/kg (log Kow method) and 5354 L/kg (MCI method) for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Executive summary:

The organic carbon partition coefficient (Koc) for 2,2-dimethylpropan-1,3-diyl dibenzoate was predicted using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11. The Koc was estimated to be 2475 L/kg (log Kow method), and 5354 L/kg (MCI method). For the estimation according to the log Kow method the measured log Kow of 4.7 was used.

The obtained log Koc values of 3.7287 (MCI method) and 3.3936 (log Kow method) indicate a moderate to strong sorption potential of 2,2-dimethylpropan-1,3-diyl dibenzoate to soil and sediment, and a negligible to slow migration potential to groundwater.

Description of key information

The QSAR determination of the carbon partition coefficient (KOC) for 2,2-dimethylpropan-1,3-diyl dibenzoate was predicted using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11. The calculated KOC values of 2475 L/kg (log Kow method) and 5354 L/kg (MCI method) refer to the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program. 

Key value for chemical safety assessment

Koc at 20 °C:

2 475

Additional information

No experimental data on adsorption properties for 2,2-dimethylpropan-1,3-diyl dibenzoate are available.

In order to predict the mobility and fate of 2,2-dimethylpropan-1,3-diyl dibenzoate in soil and sediments the organic carbon-water partition coefficient (Koc) was calculated using estimation methods following the recommendations of the ECHA guidance on information requirements and chemical safety assessment, chapter R.7a: Endpoint specific guidance document R.7a (ECHA, 2014).

 

The organic carbon partition coefficient (Koc) for 2,2-dimethylpropan-1,3-diyl dibenzoate was predicted using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11 of the U. S. Environmental Protection Agency.

The calculated KOC values of 2475 L/kg (log Kow method) and 5354 L/kg (MCI method) refer to the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program. 

The obtained log Koc values of 3.7287 (MCI method) and 3.3936 (log Kow method) indicate a moderate to strong sorption potential of 2,2-dimethylpropan-1,3-diyl dibenzoate to soil and sediment, and a negligible to slow migration potential to groundwater.

[LogKoc: 3.3936]