Cyclohexanol, 4-(1,1-dimethylethyl)-, trans-

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Data waiving:

study technically not feasible

Justification for data waiving:

the study does not need to be conducted because the substance has a high surface activity

Reference 2

Endpoint:

partition coefficient

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 adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction

Qualifier:

equivalent or similar to guideline

Guideline:

other: REACH guidance on QSARs R.6, August 2008

Principles of method if other than guideline:

The Partition coefficient is the ratio of concentrations of a tested substance in a liquid consisting of two immiscible solvents at equilibrium. The n-octanol/water partition coefficient (Kow) is one of the key physico-chemical parameters, and it is used in numerous estimation models and algorithms for environmental partitioning, sorption, bioavailability, bioconcentration/bioaccumulation and also human- and ecotoxicity. As such Kow is a critical parameter for Chemical Safety Assessment (CSA), Classification and Labelling (C&L), and PBT assessment.

The program EpiSuite 4.1 (KOWWIN) predicts logPow values. Up to 89.1 % of the predicted values are within the +/-0.5 log unit of the measured logPow value (standard error of. 0.34 log unit).

GLP compliance:

not specified

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Analytical method:

other: not applicable, estimated value

Key result

Type:

log Pow

Partition coefficient:

3.42

Temp.:

25 °C

Remarks on result:

other: calculated logPow value hence no pH

Details on results:

The program EpiSuite 4.0 (KOWWIN v1.68) predicts logPow values. Up to 89.1 % of the predicted values are within the +/-0.5 log unit of the measured logPow value (standard error of. 0.34 log unit).

Total Training Set Statistics:

(i)            number in dataset = 2447

(ii)           correlation coefficient (r²) = 0.982

(iii)          standard deviation = 0.217

(iv)         absolute deviation = 0.159

(v)          average Molecular Weight = 199.98 g/mol

 

To be effective an estimation method must be capable of making accurate predictions for chemicals not included in the training set. Currently, KOWWIN has been tested on an external validation dataset of 10,946 compounds. The validation set includes a diverse selection of chemical structures that rigorously test the predictive accuracy of any model. It contains many chemicals that are similar in structure to chemicals in the training set, but also many chemicals that are different from and structurally more complex than chemicals in the training set. The average molecular weight of compounds in the validation set is 258.98 versus 199.98 for the training set.

 

Total Validation Set Statistics:

(i)            number in dataset = 10946

(ii)           correlation coefficient (r²) = 0.943

(iii)          standard deviation = 0.479

(iv)         absolute deviation = 0.356

(v)      average Molecular Weight = 258.98 g/mol

Conclusions:

The partition coefficient n-octanol/water (log Pow) of the test item is calculated with the aid of a validated QSAR method (KOWWIN, vers. 1.68).
The result of this calculation is logPow = 3.42.

Description of key information

According to Annex VII section 7.8 Column 2 of Regulation 1907/2006 this study does not need to be conducted for substances with high surface activity.
However, a calculated value as well as details of the calculation method is provided to fulfill the requirements under REACH: logPow = 3.42 (QSAR method, KOWWIN, v1.68).

Key value for chemical safety assessment

Log Kow (Log Pow):

3.42

at the temperature of:

25 °C