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Physical & Chemical properties

Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Principles of method if other than guideline:
The test is conducted in accordance with the procedure described in EU Regulation (EC) 440/2008, Annex Part A test A.8 and OECD Test Guideline 107.

The partition coefficient (also known as distribution coefficient) is a physicochemical property of a material, which reflects the relative aqueous, and lipid solubilities and ionization behaviour. The phase distribution is independent of the concentration of dilute species.

The shake flask method is generally applicable for the determination of the partition coefficient (Log Pow) of a given material where the Log Pow value is expected to fall within the range –2 to +4. It is also applicable for essentially pure substances that are soluble in water and n-octanol but not applicable to surface-active materials.

The test is generally dependent on the Nernst Partition Law, which applies only at constant temperature, pressure and pH for dilute solutions of pure substances.
GLP compliance:
yes (incl. QA statement)
Type of method:
flask method
Partition coefficient type:
octanol-water
Analytical method:
liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
1.683
Temp.:
20 °C
pH:
7.55
Remarks on result:
other: Mean average of 6 runs
Conclusions:
The log Kow of 1-hydroxyoctan-2-one was determined to be 1.683 at 20°C and pH ~8.3 (shake flask method)
Executive summary:

The log Kow of 1-hydroxyoctan-2-one was determined to be 1.683 at 20°C and pH ~8.3 (shake flask method)

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Study period:
August 2014
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:
Results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Qualifier:
no guideline followed
Principles of method if other than guideline:
The US EPA EPI Suite v4.00 KOWWIN v1.68 model uses a "fragment constant" methodology to predict logarithm octanol-water partition coefficient (log Kow) property data.  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 Kow 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 Kow values.  KOWWIN’s "reductionist" fragment constant methodology (i.e. derivation via multiple regression) differs from the "constructionist" fragment constant methodology of Hansch and Leo (1979) that is available in the CLOGP Program (Daylight, 1995).  See the Meylan and Howard (1995) journal article for a more complete description of KOWWIN’s methodology.

To estimate log Kow, the KOWWIN v1.68 model initially separates a molecule into distinct atom/fragments.  In general, each non-hydrogen atom (e.g. carbon, nitrogen, oxygen, sulfur, etc.) in a structure is a "core" for a fragment; the exact fragment is determined by what is connected to the atom.  Several functional groups are treated as core "atoms"; these include carbonyl (C=O), thiocarbonyl (C=S), nitro (-NO2), nitrate (ONO2), cyano (-C/N), and isothiocyanate (-N=C=S).  Connections to each core "atom" are either general or specific; specific connections take precedence over general connections.
GLP compliance:
no
Key result
Type:
log Pow
Partition coefficient:
1.67
Temp.:
25 °C
pH:
ca. 7
Conclusions:
The log Kow of 1-hydroxyoctan-2-one was predicted to be 1.67 which is in excellent agreement with the experimentally determined value of 1.68
Executive summary:

The US EPA EPI Suite QSAR model software package (KOWWIN v.168) was used to predict the octanol-water partition coefficient (Kow) of 1 -hydroxyoctan-2 -one.

The following SMILES notation was used as input to the model to derive the predicted log Kow value for the substance:

CCCCCCC(CO)=O

The log Kow was predicted to be 1.67 which is in excellent agreement with the experimentally determined value of 1.68

Description of key information

The log Kow of 1-hydroxyoctan-2-one was determined to be 1.683 at 20°C and pH ~8.3 (shake flask method)

The US EPA EPI Suite QSAR model software package (KOWWIN v.168) was used to predict the octanol-water partition coefficient (Kow) of 1 -hydroxyoctan-2 -one. The log Kow was predicted to be 1.67 which is in excellent agreement with the experimentally determined value of 1.683

Key value for chemical safety assessment

Log Kow (Log Pow):
1.683
at the temperature of:
20 °C

Additional information