Octadecanoic acid, 12-hydroxy-, potassium salt

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

1. SOFTWARE: EPI Suite Version 4.11 (2012)
2. MODEL (incl. version number): MPBPVP version 1.43 (2010)
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCCCC(CCCCCCCCCCC(=O)O(K))O
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
In accordance with REACH Regulation Annex XI, studies on vapour pressure do not need to be conducted as measurement is technically not feasible. Standard test methods, according to OECD guideline 104, are able to measure vapour pressure from 10 x 10-10 Pa to 10 x 10+5 Pa. A predicted vapour pressure for potassium 12-hydroxystearate was calculated to see if it was below the OECD guideline range. The estimation of the vapour pressure (VP) was conducted using MPBPVP v1.43 in EPISuite v4.11.

In order to calculate vapour pressure, MPBPWIN uses three separate models (Antoine method, modified grain model and Mackay model). For solids, the modified grain model which is a modification and significant improvement of the modified Watson method. The modified Grain method is described as may be the best all-around VP estimation method that is currently available. The accuracy of MPBPWIN suggested VP estimate was tested on a dataset of 3037 compounds with known, experimental VP values that were between 15 and 30°C. The experimental values were taken from the PHYSPROP Database in EPISuite. Currently there is no universally accepted definition of model domain. However, property estimates are potentially considered less accurate for compounds that are outside the Molecular Weight range of the training set compounds. However, the test item has a molecular weight (338.58) which is within the Molecular weight range of 16.04-943.17 of the training set compounds. This is therefore an appropriate indication that the vapour pressure estimation can be deemed reliable in accordance to the model.

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Software tool(s) used including version: EPISuite V4.11 (2012)
- Model(s) used: MPBPVP v1.43

GLP compliance:

no

Type of method:

other: QSAR

Specific details on test material used for the study:

SMILES: CCCCCCC(CCCCCCCCCCC(=O)O(K))O
MOLECULAR FORMULA: C18 H35 O3 K1
MOLECULAR WEIGHT: 338.58

Key result

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0 Pa

Vapor Pressure Estimations (25°C):

(Using BP: 610.71°C (estimated), MP: 264.32°C (estimated))

VP: 1.66E-021 mm Hg (Antoine Method), 2.21E-019 Pa (Antoine Method)

VP: 1.61E-016 mm Hg (Modified Grain Method), 2.14E-014 Pa (Modified Grain Method)

VP: 3.51E-013 mm Hg (Mackay Method), 4.68E-011 Pa (Mackay Method)

Selected VP: 1.61E-016 mm Hg (Modified Grain Method), 2.14E-014 Pa (Modified Grain Method)

Subcooled liquid VP: 6.74E-014 mm Hg (25 deg C, Mod-Grain method), 8.99E-012 Pa (25 deg C, Mod-Grain method)

Conclusions:

The vapour pressure of potassium 12-hydroxystearate is predicted to be 2.14 E-14 Pa.

Executive summary:

In accordance with REACH Regulation Annex XI, studies on vapour pressure do not need to be conducted as measurement is technically not feasible. Standard test methods, according to OECD guideline 104, are able to measure vapour pressure from 10 x 10-10 Pa to 10 x 10+5 Pa. A predicted vapour pressure for potassium 12-hydroxystearate was calculated to see if it was below the OECD guideline range. The estimation of the vapour pressure (VP) was conducted using MPBPVP v1.43 in EPISuite v4.11. The substance has a molecular weight (338.58) which is within the Molecular weight range of 16.04-943.17 of the training set compounds. This is therefore an appropriate indication that the vapour pressure estimation can be deemed reliable in accordance to the model.

Description of key information

The vapour pressure of potassium 12-hydroxystearate is predicted to be 2.14 E-14 Pa.

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C

Additional information

In accordance with REACH Regulation Annex XI, studies on vapour pressure do not need to be conducted as measurement is technically not feasible. Standard test methods, according to OECD guideline 104, are able to measure vapour pressure from 10 x 10-10 Pa to 10 x 10+5 Pa. A predicted vapour pressure for potassium 12-hydroxystearate was calculated to see if it was below the OECD guideline range. The estimation of the vapour pressure (VP) was conducted using MPBPVP v1.43 in EPISuite v4.11. The substance has a molecular weight (338.58) which is within the Molecular weight range of 16.04-943.17 of the training set compounds. This is therefore an appropriate indication that the vapour pressure estimation can be deemed reliable in accordance to the model.