1,1,1,3,3,3-hexafluoro-2-methoxypropane

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

16 May 2019

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:

1. SOFTWARE : US EPA KowWIN v1.68a

2. MODEL (incl. version number) : US EPA KowWIN v1.68a

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL : COC(C(F)(F)F)C(F)(F)F

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL: KOWWIN uses a "fragment constant" methodology to predict log P.  In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate.   KOWWIN’s methodology is 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. A more complete description of KOWWIN’s methodology is available at Meylan, W.M. and P.H. Howard.  1995.  Atom/fragment contribution method for estimating octanol-water partition coefficients.  J. Pharm. Sci. 84: 83-92. The following validation statistics have been reported for the model:

  - number in dataset      = 10946
  - correlation coef (r2)  = 0.943
  - standard deviation     = 0.479
  - absolute deviation     = 0.356
  - avg Molecular Weight   = 258.98

Furthermore, in a peer-reviewed journal (Wen-Tien Tsai. Journal of Hazardous Materials, Vol. 119 (March 2005), p. 69 -78), the octanol-water partition coefficients of other hydrofluoroethers (HFEs) were predicted using this same method and the accuracy of the approach was validated against known measured log Kow values of four common ethers (diethyl ether, t-butyl methyl ether, n-butyl ethyl ether, and bis(2 -chloroethyl)ether). The predicted values for these ethers was within 15% of measured values suggesting that the model has a high degree of accuracy for this specific class of chemicals.

5. APPLICABILITY DOMAIN: There is no universally accepted definition of the model domain but the model is reported to be most reliable when the target substance falls within the molecular weight range of the training set and/or that have more instances of a given fragment than the maximum for all training set compounds used to estimate the log Kow. In that regard, the target substance, with a molecular weight of 182.07 and C, CH, CH3, O, and F fragments, falls well within the training set having a molecular weight range of 18.02 to 719.92, an average molecular weight of 199.98, and a large number of compounds with like frangments.

6. ADEQUACY OF THE RESULT: The predicted log Kow was 1.8071. There is no measured value against which to compare. Nonetheless, the result clearly demonstrates that, as would be expected for a molecule of this type, the substance is only slightly lipophilic.

Qualifier:

no guideline required

Principles of method if other than guideline:

QSAR Estimate using US EPA KowWIN v1.68a

GLP compliance:

no

Type of method:

other: QSAR Model

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

SMILES : COC(C(F)(F)F)C(F)(F)F
CHEM : 1,1,1,3,3,3-Hexafluoro-2-methoxypropane
MOL FOR: C4 H4 F6 O1
MOL WT : 182.07

Key result

Type:

log Pow

Partition coefficient:

1.807

Temp.:

25 °C

pH:

> 6 - < 8

Conclusions:

The estimated octanol-water partition coefficient (log Kow) is 1.8071.

Executive summary:

QSAR estimation using U.S. EPA KowWIN v1.68a predicts an octanol-water partition coefficient (log Kow) of 1.8071 at 25 deg C for the substance. In a peer-reviewed journal (Wen-Tien Tsai. Journal of Hazardous Materials, Vol. 119 (March 2005), p. 69 -78), the octanol-water partition coefficients of other hydrofluoroethers (HFEs) were predicted using this same method and the accuracy of the approach was validated against known measured log Kow values of four common ethers (diethyl ether, t-butyl methyl ether, n-butyl ethyl ether, and bis(2 -chloroethyl)ether). The predicted values for these ethers was within 15% of measured values suggesting that the model has a high degree of accuracy for this class of chemicals.

Description of key information

QSAR estimation using U.S. EPA KowWIN v1.68a predicts an octanol-water partition coefficient (log Kow) of 1.8071 at 25 deg C for the substance. In a peer-reviewed journal (Wen-Tien Tsai. Journal of Hazardous Materials, Vol. 119 (March 2005), p. 69 -78), the octanol-water partition coefficients of other hydrofluoroethers (HFEs) were predicted using this same method and the accuracy of the approach was validated against known measured log Kow values of four common ethers (diethyl ether, t-butyl methyl ether, n-butyl ethyl ether, and bis(2 -chloroethyl)ether). The predicted values for these ethers was within 15% of measured values suggesting that the model has a high degree of accuracy for this class of chemicals. Although there is no measured log Kow value for the substance, the QSAR estimate clearly demonstrates that, as would be expected for a molecule of this type, the substance is only slightly lipophilic.

Key value for chemical safety assessment

Log Kow (Log Pow):

1.807

at the temperature of:

25 °C