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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2007
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)
KOWWIN v1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
OC(CCC(O)(CC(C)C)C)(C)CC(C)C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: n-octanol-water partition coefficient
- Unambiguous algorithm: KOWWIN uses a "fragment constant" methodology to predict log P, known as an Atom/Fragment Contribution (AFC) method. Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values.
Results of the two successive multiple regressions (first for atom/fragments and second for correction factors) yield the following general equation for estimating log P of any organic compound:
log P = Σ(fini ) + Σ(cjnj ) + 0.229
(num = 2447, r2 = 0.982, std dev = 0.217, mean error = 0.159)

where Σ(fini ) is the summation of fi (the coefficient for each atom/fragment) times ni (the number of times the atom/fragment occurs in the structure) and b is the linear equation constant; Σ(cjnj ) is the summation of cj (the coefficient for each correction factor) times nj (the number of times the correction factor occurs (or is applied) in the molecule).

- 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: 18.02
Maximum MW: 719.92
Average MW: 199.98

Validation Molecular Weights:
Minimum MW: 27.03
Maximum MW: 991.15
Average MW: 258.98

- Appropriate measures of goodness-of-fit and robustness and predictivity:
The model has been tested on an external validation dataset of 10,946 compounds.
Total Validation Set Statistics:
number in dataset = 10946
correlation coef (r2) = 0.943
standard deviation = 0.479
absolute deviation = 0.356
avg Molecular Weight = 258.98

Validation Set Estimation Error:
within <= 0.20 - 39.6%
within <= 0.40 - 66.0%
within <= 0.50 - 75.6%
within <= 0.60 - 82.5%
within <= 0.80 - 91.6%
within <= 1.00 - 95.6%
within <= 1.20 - 97.7%
within <= 1.50 - 99.1%

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.
- Similarity with analogues in the training set: several linear and branched alkanes and alkenes, which are considered to be similar, are present in the training set.

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:
calculation using EpiSuite v4.11, KOWWIN v1.68, US EPA, 2012
GLP compliance:
not specified
Type of method:
other: EPI Suite QSAR
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
4.32
Remarks on result:
other: calculated
Details on results:
The notified chemical is not expected to adsorb strongly to soils due to its low water solubility. Based on the surface-active nature of the notified chemical, modelling of the partition coefficient was conducted with EPI Suite, giving an estimated logPow of 4.32.

                 Log Kow(version 1.68 estimate): 4.32

 

SMILES : OC(CCC(O)(CC(C)C)C)(C)CC(C)C

CHEM  :

MOL FOR: C14 H30 O2

MOL WT : 230.39

-------+-----+--------------------------------------------+---------+--------

 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE

-------+-----+--------------------------------------------+---------+--------

 Frag | 6 | -CH3   [aliphatic carbon]               | 0.5473 | 3.2838

 Frag | 4 | -CH2-  [aliphatic carbon]               | 0.4911 | 1.9644

 Frag | 2 | -CH    [aliphatic carbon]               | 0.3614 | 0.7228

 Frag | 2 | -OH    [hydroxy, aliphatic attach]      |-1.4086 | -2.8172

 Frag | 2 | -tert Carbon [3 or more carbon attach]  | 0.2676 | 0.5352

 Factor| 1 | Multi-alcohol correction                 | 0.4064 | 0.4064

 Const |    | Equation Constant                        |        | 0.2290

-------+-----+--------------------------------------------+---------+--------

                                                        Log Kow  =  4.3244

Conclusions:
The notified chemical is not expected to adsorb strongly to soils due to its low water solubility. Based on the surface-active nature of the notified chemical, modelling of the partition coefficient was conducted with EpiSuite v4.11, KOWWIN v1.68, giving an estimated logPow of 4.32.
Executive summary:

This substance is not expected to adsorb strongly to soils due to its low water solubility. Based on the surface-active nature of this chemical, modelling of the partition coefficient was conducted with EpiSuite v4.11, KOWWIN v1.68, giving an estimated logPow of 4.32.

Endpoint:
partition coefficient
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Study period:
2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: calculated according to EC Directive 92/69/EEC and Regulation EC/440/2008 guideline methods (OECD 117)
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
GLP compliance:
not specified
Type of method:
other: calculation according to CLOGP
Partition coefficient type:
octanol-water
Analytical method:
other: calculation by CLOGP
Type:
log Pow
Partition coefficient:
3.8
Remarks on result:
other: calculated
Details on results:
The notified chemical is not expected to adsorb strongly to soils due to its low water solubility. Based on the surface-active nature of the notified chemical, modelling of the partition coefficient was conducted with EPI Suite v3.20, giving an estimated logPow of 4.32. Using OECD TG 117 by calculation, logPow was estimated to be 3.8.
Conclusions:
The notified chemical is not expected to adsorb strongly to soils due to its low water solubility. Using OECD TG 117 by calculation, logPow was estimated to be 3.8.
Executive summary:

The logKow of 2,4,7,9-tetramethyldecane-4,7-diol was calculted according to the method established in OECD guideline 117 CLOGP. This substance is not expected to adsorb strongly to soils due to its low water solubility. Using OECD TG 117 by calculation, logPow was estimated to be 3.8.

Description of key information

Test not conducted. Values were estimated using EPI Suite v3.20 and OECD TG 117 Partition Coefficient (n-octanol/water).
logPow = 3.8 (CLOGP)
logPow = 4.32 (KOWWIN)
The distribution coefficient was estimated by the HPLC method using isocratic elution. The procedure conformed to those outlined in OECD Guideline 121 and EC Directive 2001/59/EC Method C19.
LogKoc = 3.88, within a 95% confidence range of 3.46 to 4.44

Key value for chemical safety assessment

Log Kow (Log Pow):
3.8
at the temperature of:
25 °C

Additional information

logPow is estimated to range between 3.8 and 4.32 according to calculations and QSAR estimations.