Octadecan-1-ol, ethoxylated

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

mixture rules calculation

Adequacy of study:

weight of evidence

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

QSAR prediction

Principles of method if other than guideline:

The calculations were performed for the linear free alcohols and ethoxylated alcohols (AE) with ethoxylation degree of 1 and 3, respectively, using KOWWIN v1.68, Estimation Programs Interface Suite™ for Microsoft® Windows v4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.
In order to derive a single value for risk assessment, the various calculated vapour pressure values were weight-averaged using normalized values for composition (linear free alcohols and C18 AE).

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

7.3

Remarks on result:

other: weight-averaged value

QSAR result; pH and temperature are not reported. For detailed description of the model and its applicability, see "Any other information on materials and methods incl. tables".

Individual calculated values for log Pow (taken from the EPIsuite v 4.10 report, 2012)

structure	SMILES notation used in calculation	EPI log Pow calc.
Alcohol, C18	CCCCCCCCCCCCCCCCCCO	7.72
Alcohol ethoxylate, C18, 1 EO	CCCCCCCCCCCCCCCCCCOCCO	7.44
Alcohol ethoxylate, C18, 3 EO	CCCCCCCCCCCCCCCCCCOCCOCCOCCO	6.89

 

Mean calculated values for log Pow for each ‘sub’-group

	Mean log Pow calc.
Free alcohol	7.72
C18-EO (avg of 1EO and 3EO)	7.17

 

Result:

Weight-averaged log Pow of the whole substance based on normalized composition: 7.30

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2-11 Mar 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

GLP compliance:

yes

Type of method:

slow-stirring method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

> 7.06

Temp.:

25 °C

pH:

>= 5.2 - <= 5.3

The concentration of the test item in the aqueous and 1 -octanol phase was determined after 68, 70, 72 and 74 hours, ensuring that an equilibrium concentration was established in both phases. At each test time, three different test solutions were analysed. The results are given in the table:

Time (h)	Octanol phases, test mixture (mg/g)			Aqueous buffer phases, test mixture (µg/g)
	1	2	3	1	2	3
68	34.91	35.28	35.35	< 0.003095	< 0.003095	< 0.003095
70	35.25	34.97	35.41	< 0.003095	< 0.003095	< 0.003095
72	35.31	35.54	35.47	< 0.003095	< 0.003095	< 0.003095
74	35.76	35.39	35.65	< 0.003095	< 0.003095	< 0.003095

For each time interval the Pow and log Pow values are calculated for each test mixture. The results are summarized in the table:

Time (h)	Calculated Pow values, test mixture no.			Calculated log Pow values, test mixture no.
	1	2	3	1	2	3
68	>11280000	>11400000	>11420000	>7.052	>7.057	>7.058
70	>11390000	>11300000	>11440000	>7.056	>7.053	>7.058
72	>11410000	>11480000	>11460000	>7.057	>7.060	>7.059
74	>11550000	>11430000	>11520000	>7.063	>7.058	>7.061

pH values of aqueous phases varied between 5.2 and 5.3.

Reference 3

Endpoint:

partition coefficient

Type of information:

mixture rules calculation

Adequacy of study:

weight of evidence

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Calculation from experimentally derived Koc data using an equation from the 2003 EU Technical Guidance Document on Risk Assessment Part III, Chapter 4, Section 4.3

Qualifier:

according to guideline

Guideline:

other: 2003 EU Technical Guidance Document on Risk Assessment Part III, Chapter 4, Section 4.3, p. 26

Deviations:

no

Principles of method if other than guideline:

Log Kow was calculated using an equation derived from experimentally determined Koc values for analogue structures using the 2003 TGD equation for predominantly hydrophobic substances.

GLP compliance:

no

Type of method:

other: calculation from log Koc values

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

6.84

Remarks on result:

other: weight-averaged value

Details on results:

Weight-averaged log Koc of the whole substance based on normalized composition: 5.64.
This value was used in the rearranged TDG equation mentioned above resulting in a log Pow value of 6.84.

Description of key information

log Pow - experimental value: > 7.06 at 25 °C, pH 5.2 -5.3 (OECD 123, slow-stirring method)

log Pow - calculated from weight-averaged log Koc value: 6.84 (calculation based on 2003 EU TGD)
log Pow - calculated using KOWWIN v1.68 (weight-averaged value): 7.30 (EPIsuite v4.10)

Key value for chemical safety assessment

Log Kow (Log Pow):

7.07

Additional information

The log Pow of the substance was determined experimentally using the slow-stirring method according to OECD Guideline 123. It was the second determination employing this method: the value obtained earlier was unexpectedly low. The analytical method to support the test involved ELSD. Since no reference substances for the pure alcohol or a purified C18 AE species were tested, it was not possible to deduce which, if any, of the possible constituents caused the ELSD response.

The key value for chemical safety assessment, log Pow = 7.07 was derived in a weight-of-evidence approach from the various calculated log Pow values (average of 2 calculated values 6.84 and 7.30) for the query substance. The value is in agreement with the recent OECD 123 experiment.

 

The following types of calculations were applied:

1. based on weight-averaged log Koc values using the TGD equation for predominantly hydrophobic substances: log Koc = 0.81 log Pow + 0.10 thus log Pow = (log Koc – 0.10)/0.81 (2003 EU Technical Guidance Document on Risk Assessment Part III, Chapter 4, Section 4.3, pp 24 – 27)

2. based on EPIsuite v 4.10, KOWWIN v 1.68 log Pow values for (possible) individual constituents of the substance; a weighting based on normalized composition was applied to derive a log Pow value for the whole substance. Only the weight-averaged value was used as input value for derivation of the key value for chemical safety assessment.