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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Principles of method if other than guideline:
No details are available on the guideline used to determine this result.
GLP compliance:
not specified
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
5.36
Conclusions:
A log Kow value of 5.36 was reported for the substance.
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 recognised source of physico-chemical data. This reference is considered as definitive for octanol-water partition coefficient values.
Principles of method if other than guideline:
No details are available on the guideline used to determine this result.
GLP compliance:
not specified
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
5.13
Remarks on result:
other: The pH at which the log Kow was measured is not stated, but it is consistent with expected properties of the substance in its non-ionised state. The temperature is not stated.
Conclusions:
A partition coefficient (log Kow) value of 5.13 was reported in a collection of reliable data which has been subject to peer-review . The result is considered to be reliable.
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2009-04-30
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test procedure in accordance with national standard methods (OECD) without GLP.
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
no
GLP compliance:
no
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
5.4
Temp.:
23 °C
pH:
7.1
Remarks on result:
other: Result for the dodecan-1-ol constituent of this multi-constituent test substance.

Calibration

For calibration 20 -30 mg of the reference samples and of thio urea (dead time determination) are weighed into a 100 ml volumetric flask and filled up to 100 ml of a methanol-water mixture (80:20). This calibration mixture (L090443) is then analysed by the reported chromatographic conditions.

substances log Pow  retention time (min.)  capacity factor k  log k 
phenylbenzoate  3.6  2.13  0.593  -0.23 
diphenyl ether  4.2  2.63  0.964  -0.02 
dibenzyl  4.8  3.90  1.913  0.28 
flouranthene  5.1  4.86  2.633  0.42 
triphenylamine  5.7  6.07  3.538  0.55 

correlation log k and Pow

slope: 2.52

axis intercept: 4.17

correlation coefficient: 0.991

Measurement

200 -300 mg of the test sample are weighed into a 100 ml volumetric flask and filled up to 100 ml with methanol.

retention time (minutes) for C12: 5.61

peak area for C12: 222137

capacity factor for C12: 3.19

log k for C12: 0.50

log POW for C12: 5.4

retention time (minutes) for C14: 11.56

peak area for C14: 80213

capacity factor k for C14: 7.64

log k for C14: 0.88

log POW for C14: 6.4

Conclusions:
A log Kow value of 5.4 at 23°C and pH 7.1 was obtained for the substance using a relevant test method. The result is considered to be reliable.
Executive summary:

Alcohols, C12 -14 was determined according OECD Guideline 117. The partition coefficient of Dodecan-1 -ol was determined to be log Pow 5.4 at 23 °C and a pH of 7.1.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting 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
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
4.8

Measurement

Log Pow: 4.8

Conclusions:
A log Kow value of 4.8 was obtained for the substance using a relevant test method. The result is considered reliable.
Executive summary:

Dodecan-1 -ol was determined according ASTM E 1147. The partition coefficient was determined to be log Pow 4.8.

Description of key information

The octanol-water partition coefficient of a commercial dodecan-1-ol product is 5.4 (by HPLC method).

Key value for chemical safety assessment

Log Kow (Log Pow):
5.4
at the temperature of:
23 °C

Additional information

The log octanol/water partition coefficient of 5.4 at 23°C and pH 7.1 was determined for the dodecan-1 -ol constituent in a study with Alcohols C12 -14 in accordance with OECD 117. The result is considered to be reliable.

It is supported by a reliable value of 5.13, believed to have been determined in a shake-flask test (Hansch et al, 1995); a reliable value of 5.36, taken from a reliable reference source for partitioning data (Burkhard, 1985, by HPLC). A value of 4.8 is available from a second reliable study.

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.