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Physical & Chemical properties

Partition coefficient

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Administrative data

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Endpoint:
partition coefficient
Type of information:
other: Data obtained from a collection of reliable data
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Method: other (measured)
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
7.19
Conclusions:
A log Kow value of 7.19 was reported for the substance in a collection of reliable data.
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:
test procedure in accordance with national standard methods with acceptable restrictions
Remarks:
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:
7.4
Remarks on result:
other: The temperature of the measurement is not reported.

Measurement

Log Kow: 7.4

Conclusions:
A log Kow value of 7.4 was determined for the substance using a relevant test method. The result is considered to be reliable.
Executive summary:

Octadecan-1-ol was determined according ASTM E 1147 . The partition coefficient was determined to be logPow 7.4.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2009-04-30
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Remarks:
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
Specific details on test material used for the study:
The study was conducted on a mixture of Alcohols, C16 and C18 using chromatography method. The result is for C18 alcohol.
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
8.2
Temp.:
23 °C
pH:
7.1

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 C16:25.36

peak area for C16:73668

capacity factor for C16:17.95

log k for C16:1.25

log POW for C16:7.3

retention time (minutes) for C18:56.55

peak area for C18:192267

capacity factor k for C18:41.26

log k for C18:1.62

log POW for C18:8.2

Conclusions:
A log Kow value of 8.2 at 23°C and a pH of 7.1 was determined for the substance using a relevant test method. The result is considered to be reliable.
Executive summary:

Octadecan-1-ol was determined according OECD Guideline 117. The partition coefficient was determined to be 8.2 at 23 °C and a pH of 7.1.

Description of key information

The octanol-water partition coefficient of octadecan-1-ol is 7.4 (by HPLC method) for a commercial sample. A value of 7.19 is available determined by HPLC for a pure sample and reported in reliable published literature source (HPLC).

Key value for chemical safety assessment

Log Kow (Log Pow):
7.4

Additional information

A log n-octanol/water partition coefficient of 7.4 was determined for octadecan-1-ol in accordance with ASTM E 1147. The result is considered to be reliable.

It is supported by a value of 7.19 determined by HPLC for a pure sample and reported in published literature, and a value of 8.2 determined for C18 from a study of a multi-constituent commercial substance by HPLC.

The value taken from literature for pure alcohol (7.19) 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.