Benzoic acid, C12-15-alkyl esters

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

supporting 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
EpiSuite v4.11, US EPA, 2012

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

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Representative structures
C(=O)(c1ccccc1)OCCCCCCCCCCCC
C(=O)(c1ccccc1)OCCCCCCCCCCCCC
C(=O)(c1ccccc1)OCCCCCCCCCCCCCC
C(=O)(c1ccccc1)OCCCCCCCCCCCCCCC
C(=O)(c1ccccc1)OCC(C)CCCCCCCCCC
C(=O)(c1ccccc1)OCC(CCCCCCCCCC)CC
C(=O)(c1ccccc1)OCCCCCCCCCC(C)(C)C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Koc
MCI (molecular connectivity index) method
The equation derived by the non-polar (no correction factor) regression is:
log Koc = 0.5213 MCI + 0.60
(n = 69, r2 = 0.967, std dev = 0.247, avg dev = 0.199)
for comparison, the previous version of PCKOCWIN used a very similar equation:
log Koc = 0.53 MCI + 0.62
Adding in the correction factor regression yields the final MCI equation:
log Koc = 0.5213 MCI + 0.60 + ΣPfN
where ΣPfN is the summation of the products of all applicable correction factor coefficients multiplied by the number of times (N) that factor is counted for the structure.

- Defined domain of applicability:
Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that log P estimates are less accurate for compounds outside the MW range of the training set compounds, and/or that have more instances of a given fragment than the maximum for all training set compounds. It is also possible that a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed. These points should be taken into consideration when interpreting model results.

Training Set Molecular Weights:
Minimum MW: 32.04
Maximum MW: 665.02
Average MW: 224.4
Validation Molecular Weights:
Minimum MW: 73.14
Maximum MW: 504.12
Average MW: 277.8

- Appropriate measures of goodness-of-fit and robustness and predictivity:
Overall, the MCI methodology is somewhat more accurate than the Log Kow methodology, although both methods yield good results. If the Training datasets are combined in to one dataset of 516 compounds (69 having no corrections plus 447 with corrections), the MCI methodology has an r2, standard deviation and average deviation of 0.916, 0.330 and 0.263, respectively.

5. APPLICABILITY DOMAIN
- Descriptor domain: The components of the substance are within the molecular weight range of the training set compounds, and all fragments are represented in the training set. Thus, it is concluded, that the substance is within the applicability domain.

6. ADEQUACY OF THE RESULT
The QSAR prediction is valid and of good reliability. Thus, the result is adequate for chemical safety assessment.

Principles of method if other than guideline:

The Koc of the constituents was estimated using EpiSuite v4.11, US EPA, 2012, KOCWIN v2.00 (MCI method) in batch mode.

GLP compliance:

no

Remarks:

n.a. for in silico study

Type of method:

other: QSAR

Specific details on test material used for the study:

Representative structures used for modelling:
C(=O)(c1ccccc1)OCCCCCCCCCCCC
C(=O)(c1ccccc1)OCCCCCCCCCCCCC
C(=O)(c1ccccc1)OCCCCCCCCCCCCCC
C(=O)(c1ccccc1)OCCCCCCCCCCCCCCC
C(=O)(c1ccccc1)OCC(C)CCCCCCCCCC
C(=O)(c1ccccc1)OCC(CCCCCCCCCC)CC
C(=O)(c1ccccc1)OCCCCCCCCCC(C)(C)C

Type:

Koc

Value:

>= 49 480 - <= 299 500 L/kg

Transformation products:

not measured

Representative structure	Koc Estimate from MCI [L/kg]
C(=O)(c1ccccc1)OCCCCCCCCCCCC	4.948e+04
C(=O)(c1ccccc1)OCCCCCCCCCCCCC	9.017e+04
C(=O)(c1ccccc1)OCCCCCCCCCCCCCC	1.643e+05
C(=O)(c1ccccc1)OCCCCCCCCCCCCCCC	2.995e+05
C(=O)(c1ccccc1)OCC(C)CCCCCCCCCC	7.938e+04
C(=O)(c1ccccc1)OCC(CCCCCCCCCC)CC	1.514e+05
C(=O)(c1ccccc1)OCCCCCCCCCC(C)(C)C	5.899e+04

Conclusions:

The Koc of representative structures of C12-14 Alkylbenzoate was estimated using EpiSuite v4.11, US EPA, 2012, KOCWIN v2.00 (MCI method) in batch mode. The Koc ranged from 4.948e+04 to 2.995e+05 L/kg.

Description of key information

The Koc of representative structures of C12-14 Alkylbenzoate was estimated using EpiSuite v4.11, US EPA, 2012, KOCWIN v2.00 (MCI method) in batch mode. The Koc ranged from 4.948e+04 to 2.995e+05 L/kg.

Key value for chemical safety assessment

Koc at 20 °C:

299 500