Hexadecan- l-ol, ethoxylated

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Jan - 6 Feb 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:

no

Type of method:

slow-stirring method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

> 6.06

Temp.:

25 °C

pH:

>= 5.16 - <= 5.25

The concentration of the test item in the aqueous and 1 -octanol phase was determined after 66, 68, 70 and 72 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 phases, test mixture (mg/g)
	1	2	3	1	2	3
66	29.63	29.96	29.93	< 0.00002619	< 0.00002619	< 0.00002619
68	29.32	29.41	29.50	< 0.00002619	< 0.00002619	< 0.00002619
70	29.50	30.09	30.06	< 0.00002619	< 0.00002619	< 0.00002619
72	29.86	30.02	29.93	< 0.00002619	< 0.00002619	< 0.00002619

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			Calculated log Pow values, test mixture
	1	2	3	1	2	3
66	> 1131116.6	> 1143826.6	> 1142536.5	> 6.054	> 6.058	> 6.058
68	> 1119224.0	> 1123306.7	> 1126036.2	> 6.049	> 6.050	> 6.052
70	> 1126267.2	> 1148519.7	> 1147336.5	> 6.052	> 6.060	> 6.060
72	> 1140394.6	> 1146355.9	> 1142514.0	> 6.057	> 6.059	> 6.058

pH values of aqueous phases were 5.18, 5.25 and 5.16, for mixtures 1, 2 and 3, respectively.

Reference 2

Endpoint:

partition coefficient

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Study period:

7 Jul 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Qualifier:

according to guideline

Guideline:

other: Computational Approach in OECD Guideline 107 (EU A.8)

Principles of method if other than guideline:

According to the guidance of the ECHA a ratio calculation is an acceptable alternative for the determination of octanol/water Partition Coefficient of surfactants.
Citation from ''Guidance on information requirements and chemical safety assessment Chapter R.7a: Endpoint specific guidance'', R.7.1.8 Partition Coefficient, page 102:
This method enables partition coefficient to be calculated based on the ratio of the solubility of the material in octanol and water. For some substances (e.g. some surfactants and pigments), it is technically not feasible (or good practice) to measure an octanol-water partition coefficient by OECD 107, and other methods (OECD 117 and QSAR) may be unsuitable as they are based on extrapolations of measured values. For such substances it may be possible to obtain a ratio of the saturated water solubility (OECD 105) and saturated octanol solubility (no guideline currently available but based on the principles of OECD 105). The calculation method however has the drawback that it does not include the interaction between the water and solvent phase (i.e. a chemical with high Pow is rather ‘pushed out of the water’ than ‘pulled into octanol’). This explains the poor correlation typically observed between octanol solubility and Kow (Dearden, 1990, Sijm et al., 1999). The ratio was found somewhat more representative if one uses octanol/saturated water and water/saturated octanol.

GLP compliance:

no

Type of method:

other: calculated

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

7.7

Temp.:

20 °C

pH:

6

Remarks on result:

other: mean of 6.4 and 9.0

n-Octanol solubility of the test item: > 2.3 kg/L or rather unlimited at 20 °C

Water solubility of the test item: < 2.15 µg/L to 910.5 µg/L at 20 °C

Boundary values:

Pow(max) > 2.3 kg/2.15 µg = 1.07 E+09; log Pow > 9.0

Pow(min) = 2.3 kg/910.5 µg = 2.53E*06; log Pow = 6.4

Thus log Pow is in the range from 6.4 to > 9.0 . Average value: 7.7.

 

Reference 3

Endpoint:

partition coefficient

Type of information:

mixture rules calculation

Adequacy of study:

supporting study

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EPI Suite v4.11 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
KOWWIN v1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Overall remarks, attachments" section.

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.

Principles of method if other than guideline:

The calculations were performed for the ethoxylated alcohols (AE) with ethoxylation degree of 1 and 3, respectively, using KOWWIN v1.68, Estimation Programs Interface Suite™ for Microsoft® Windows v4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

6.19

Remarks on result:

other: 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 4.11 report, 2018)

structure	SMILES notation used in calculation	EPI log Pow calc.
Alcohol ethoxylate, C16, 1 EO	CCCCCCCCCCCCCCCCOCCO	6.46
Alcohol ethoxylate, C16, 3 EO	CCCCCCCCCCCCCCCCOCCOCCOCCO	5.91

 

Result:

Averaged log Pow of the whole substance: 6.19

Reference 4

Endpoint:

partition coefficient

Type of information:

mixture rules calculation

Adequacy of study:

supporting study

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:

6.11

Remarks on result:

other: averaged value

Details on results:

Weight-averaged log Koc of the whole substance based on the composition: 5.05.
This value was used in the rearranged TDG equation mentioned above resulting in a log Pow value of 6.11.

Description of key information

Key study:

log Pow - determined experimentally: > 6.06 at 25 °C (OECD 123)

Supporting data:

log Pow – calculated on the basis of solubilities in n-octanol and water: 7.70 (OECD 107, EU A.8)
log Pow - calculated from averaged log Koc value: 6.11 (calculation based on 2003 EU TGD)
log Pow - calculated using KOWWIN v1.68 (averaged value): 6.19 (EPIsuite v4.11)

Key value for chemical safety assessment

Log Kow (Log Pow):

6.67

at the temperature of:

20 °C

Additional information

Since the key study (slow stirring experiment according to OECD Guideline 123) results in a value given as > 6.06, supporting studies (in agreement with the key result) are used for the determination of the definite value for the chemical safety assessment.

The log Pow of 7.70 for the substance Hexadecan-1-ol, ethoxylated, < 2.5 EO (CAS 9004-95-9) was determined as the ratio of solubilities in n-octanol and water (computational method in OECD 107, EU A.8).

According to the approach developed for the Alcohol Ethoxylate Category, the value for chemical safety assessment logPow = 6.67 is derived in a weight-of-evidence approach on the basis of various log Pow values (average of 3 calculated values: 7.70, 6.11 and 6.19).

 

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.The averaged value was used as input value for derivation of the key value for chemical safety assessment.