Docosan-1-ol

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-01-13

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

Key result

Type:

log Pow

Partition coefficient:

8.3

Remarks on result:

other: The temperature of the measurement is not reported.

Measurement

Log Kow: 8.3

Conclusions:

A log Kow value of 8.3 at 20°C and pH 7 was determined for the substance using a relevant test method. The result is considered to be reliable.

Executive summary:

Docosan-1-ol was determined according ASTM E 1147 . The partition coefficient was determined to be log P_ow 8.3 at 20°C and pH 7.

Description of key information

The log octanol-water partition coefficient of a commercial sample of docosan-1-ol is 8.3 (by HPLC method) at 20°C and pH 7. A log Kow value of 7.75 would be predicted for the pure linear alcohol based on category trends.

Key value for chemical safety assessment

Log Kow (Log Pow):

8.3

at the temperature of:

20 °C

Additional information

The log octanol/water partition coefficient of 8.3 at 20°C and pH 7 was determined for docosan-1-ol in accordance with ASTM E 1147. The result is considered to be reliable.

Trends in the value of log K_ow across the category have been examined across the homologous series covered by the C6 -24 Alcohols category based on reliable literature for pure alcohol samples. A predictive equation based on the carbon chain length has been derived. This shows that the value of log K_ow derived by the equation reaches a peak at around C20 and then begins to drop again. It would be expected that, experimentally, values of log Kow reach a plateau and that the values would not drop again. Therefore for docosan-1-ol, the log Kow value for a pure alcohol is predicted to be 7.75, the same as the reliable literature measurement for the neighbouring alcohol, icosan-1-ol C20.

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.