Oligo

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

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 version 4.11

2. MODEL (incl. version number)
Mpbpwin v. 1.43

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 "Any other information on results incl. tables".

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

Qualifier:

according to guideline

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

- Software tool(s) used including version: EPI Suite v4.11
- Model(s) used: Mpbpwin Model version 1.43
The model estimates vapour pressure by three different methods:
- the Antoine equation (Lyman WJ, Reehl WF and Rosenblatt DH. 1990. Handbook of Chemical Property Estimation Methods. Washington, DC: American Chemical Society);
- the Modified Grain Method (Lyman WJ. 1985. In: Environmental Exposure From Chemicals. Volume I. Neely WB and Blau GE (eds). Boca Raton, FL: CRC Press, Inc., Chapter 2);
- the Mackay Method (Lyman WJ. 1985. In: Environmental Exposure From Chemicals. Volume I. Neely WB and Blau GE (eds). Boca Raton, FL: CRC Press, Inc.).
MPBPWIN selects a “suggested” vapour pressure: the modified Grain for solids and the average of the Antoine and the modified Grain for liquids and gases.
A dataset of 3037 compounds with experimentally determined vapour pressure values has been used to evaluate the model (using the “suggested” values as outcome), giving a correlation coefficient of 0.914. The evaluation clearly shows that the model reliability decrease for vapour pressure below 0.0001 Pa.
The dataset contains 1642 compounds with available experimental Boiling points and Melting points. The correlation coefficient evaluated on this subset (0.949) indicates that VP estimates are more accurate when experimental BP and MP are available.

- Model description: see field 'Justification for type of information', 'Attached justification' and 'any other information on Material and methods'
- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'overall remarks'

GLP compliance:

no

Type of method:

other: QSAR

Temp.:

25 °C

Vapour pressure:

< 0 Pa

QSAR result; transition/decomposition is not specified/reported. For detailed description of the model and its applicability, see "Any other information on materials and methods incl. tables”.

Results obtained for the four evaluated representative molecules of the target substances are summarized in the following table. For more information see "Attached full study report".

Molecule	Vapour Pressure at 25 °C [Melting point: 65.4] (Pa)	Vapour Pressure at 25 °C [Melting point: 68.2] (Pa)
C16 Monoester	1.37E-018	1.29E-018
C18 Diester	1.01E-025	7.09E-028
C18 Pentaester	0	0
C18 Octaester	0	0

The Modified Grain Method was selected by EPI Suite for all estimations.

The highest vapour pressure values were calculated for the C16 Monoester constituent. Furthermore, the other constituents are characterized by high molecular weights and might not fall within the applicability domain of the model. The results obtained for the C16 Monoester molecule will be therefore used to represent the whole substance.

 

Conclusion

Based on the calculated values, a vapour pressure < 0.0001 Pa can be considered as a reasonable estimation for the target substance.

Reference 2

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

16 Nov 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The Limit of Quantification of the method used is higher than expected based on OECD Guideline 104.

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

March 23, 2006

Deviations:

no

GLP compliance:

no

Type of method:

static method

Temp.:

25 °C

Vapour pressure:

< 133 Pa

Remarks on result:

other: LOQ of the method is 133 Pa

Temp.:

50 °C

Vapour pressure:

< 133 Pa

Remarks on result:

other: LOQ of the method is 133 Pa

The value was regarded as <133 Pa because the vapour pressure was under the limit of quantification.

Description of key information

Vapour pressure <0.0001 Pa at 25 °C (QSAR, EPI Suite 4.11, Mpbpwin v. 1.43)

Additional information

Experimental study available: vapour pressure < 133 Pa (OECD Guideline 104, static method)

The value was regarded as <133 Pa because the vapour pressure was under the limit of quantification (LOQ).

QSAR evaluation was performed on four representative constituents of the substance, with a maximum vapour pressure estimated as 1.37E-018 Pa at 25 °C. Based on such low estimations, a vapour pressure < 0.0001 Pa was used to describe the substance as a whole.