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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-10-09
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test procedure in accordance with national standard methods (ASTM) without GLP.
Qualifier:
according to guideline
Guideline:
other: ASTM E 1147
Deviations:
no
GLP compliance:
no
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
1.8
Remarks on result:
other: The temperature of the measurement is not reported.

Measurement

Log Kow: 1.8

Executive summary:

Hexan-1-ol was determined according ASTM E 1147 . The partition coefficient was determined to be 1.8.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Value obtained from a database which is peer-reviewed; original source is considered authoritative for partition coefficient values.
Principles of method if other than guideline:
The generator column was coated with liquid solute and 1-octanol. Water was then pumped into the column. Analysis of the aqueous phase from the 1% octanol coated column was used to determine the Kow.
GLP compliance:
not specified
Type of method:
generator column method
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
2.03
Temp.:
25 °C

The pH at which the log Kow was measured is not known, but stated but it is consistent with expected properties of the substance in its non-ionised state.

Conclusions:
A partition coefficient value of 2.03 is reported in a collection of reliable data which has been subject to peer-review and in which the original data sources are traceable. The result is considered to be reliable.

Description of key information

The log octanol-water partition coefficient of a commercial hexan-1-ol product is 1.8 (by HPLC method). A value of 2.03 at 25°C, is cited in a reliable and definitive reference source for partitioning data (Hansch and Leo, 1995, Tewari 1982).

Key value for chemical safety assessment

Log Kow (Log Pow):
1.8

Additional information

The log octanol/water partition coefficient of 1.8 was determined for hexan-1-ol in accordance with ASTM E 1147. The result is considered to be reliable.

It is supported by a value of 2.03 at 25°C, taken from a reliable and definitive reference source for partitioning data (Hansch and Leo, 1995, Tewari 1982).

The value taken from literature for pure alcohol is used in exposure modelling.

Discussion of trends in the Category of C6-24 linear and essentially-linear aliphatic alcohols:

As chain length increases, the free energy required for a molecule to dissolve becomes less favourable for larger molecules. The octanol-water partition coefficient increases with molecular weight because each additional -CH2- group makes the octanol phase more preferred over water in terms of relative solvation energy.