Octadecan-1-ol, ethoxylated

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

other: experimental determination and calculation

Adequacy of study:

weight of evidence

Study period:

08 - 18 Aug 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Remarks:

including experimental determination assumed questionable for measured range.

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

GLP compliance:

no

Type of method:

other: Grain-Watson estimation and analysis of vapour pressure curve from a DSC experiment

Temp.:

20 °C

Vapour pressure:

0 Pa

Remarks on result:

other: Grain-Watson estimation

Temp.:

20 °C

Vapour pressure:

0 Pa

Remarks on result:

other: 3.1E-6 mbar, experimental value

No information on transition / decomposition is given.

The experimentally determined vapour pressure of the substance at 20 °C was 3.1 x 10^-6 mbar, thus well outside the recommended range of 1 -1000 mbar. Therefore, this result was considered not reliable and was the Grain-Watson estimation method applied to derive a more reliable vapour pressure value. (the newest version of the estimation method was used - (R. S. Boethling, D. Mackay, Handbook of property estimation methods for chemicals; Lewis publishers, 2000, Cap. 3, p.53 -65). This method is applicable for vapour pressure between 10^3 to 10^-7 mbar.

Reference 2

Endpoint:

vapour pressure

Type of information:

mixture rules calculation

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

QSAR prediction. Calculation based on MPBPWIN v1.43, Estimation Programs Interface Suite™ for Microsoft® Windows v4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

Principles of method if other than guideline:

Calculation based on MPBPWIN v1.43, Estimation Programs Interface Suite™ for Microsoft® Windows v4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

GLP compliance:

no

Type of method:

other: QSAR

Temp.:

20 °C

Vapour pressure:

0 Pa

Remarks on result:

other: weight-averaged value

QSAR result; transition/decomposition is 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 vapour pressure (taken from the EPIsuite v 4.10 report, 2012)

structure	SMILES notation used in calculation	EPI vp calc. [Pa @ 20°C]
Alcohol, C18	CCCCCCCCCCCCCCCCCCO	0.000109
Alcohol ethoxylate, C18, 1 EO	CCCCCCCCCCCCCCCCCCOCCO	0.00000231
Alcohol ethoxylate, C18, 3 EO	CCCCCCCCCCCCCCCCCCOCCOCCOCCO	0.00000000394

 

The estimated values are below 0.0001333 Pa (1E-6 mmHg). The estimation error increases with the decrease ofthe vapour pressure and is significantly higher for pressures below 0.0001333 Pa (1E-6 mmHg), therefore the limit value of 0.0001333 Pa is taken as a vapour pressure of the components of the substance.

Mean calculated values for vapour pressure for each ‘sub’-group

	Mean calc. vp [Pa @ 20°C]
Free alcohol	0.0001333
C18-EO (avg of 1EO and 3EO)	0.0001333

 

Result:

Weight-averaged vapour pressure of the whole substance based on normalized composition: 0.0001333 Pa.

Description of key information

calculated value: 0.00011 Pa at 20 °C (OECD 104, Grain-Watson estimation method)
experimental value: 0.00031 Pa at 20 °C (based on boiling point measurements at different pressures)
estimated by calculation (based on modified Grain method, weight-averaged value): 0.0001333 Pa at 20 °C (EPIsuite v4.10)

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

20 °C

Additional information

The vapour pressure of substance was determined experimentally using boiling point measurements at different pressures and estimated by calculation based on the Grain-Watson Method (according to OECD 104) or the modified Grain method (EPIsuite v4.10).

 

The experimental value was considered to be not reliable, as it fell outside the recommended range for DSC-based vapour pressure deduction (range: 1-1000 mbar). Alternatively, the Grain-Watson estimation procedure according the OECD Method 104 was applied, which takes into account melting point and boiling point data. 

 

Additionally, the vapour pressures of possible individual constituents of the substance were calculated using EPIsuite v 4.10 (MPBPVP v 1.43). In order to derive a vapour pressure value for the whole substance, weighting based on normalized composition was applied to the individual data. Since the resulting weighted value of is below 0.0001333 Pa (1E-6 mmHg), below which the estimation error increase significantly, therefore the limit value of 0.0001333 Pa is taken as a vapour pressure of the whole substance obtained with MPBPVP v 1.43.

 

In view of the low vapour pressure values obtained from the calculations, simple average of two estimations 0.00011 Pa and 0.000133 Pa are used to derive the key value of 0.0001215 Pa at 20 °C for chemical safety assessment.