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Physical & Chemical properties

Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
The measurement of vapor pressure for chemical substances of unknown or variable composition (UVCB) is often complex, as substances can contain many constituents each with their own vapor pressures and specific chemical characteristics. Vapor pressure is a chemical specific property, which is important in evaluating the behaviour and fate of a chemical substance in the environment. In most of the cases, methodologies require the experimenter to know the molecular mass of the substance being tested, which is often not possible for a UVCB. Additionally, extensive analytical development can potentially be required to obtain vapor pressure results with no guarantee of an accurate or valid result, making this a less attractive approach. Moreover, the vapor pressure of the substance resin acids and rosin acids, maleated, esters with glycerol is expected to be very low based on comparison with similar substances. After consideration of all these factors, the authors recommend the use of a QSAR approach as the most appropriate method to proceed.

Qualifier:
no guideline required
Principles of method if other than guideline:
- Software tool(s) used including version:
- Model(s) used: EPISuite v4.11 (Estimation Program Interface), MPBPVP v1.43 (Melting and boiling points, vapor pressure) (US EPA 2012).
- Using the MPBPWIN model, vapor pressure is estimated by three methods and all three use the boiling point. Unless the user enters a boiling point on the data entry screen, MPBPWIN uses the estimated boiling point from the adapted Stein and Brown method.
The Antoine method (Lyman 1990) was developed for liquids and gases. MPBPWIN extended the Antoine method to make it applicable to solids using the same methodology as the modified Grain method to convert a super-cooled liquid vapor pressure to a solid phase vapor pressure. The modified Grain method (Lyman 1985) , is an improvement to the modified Watson method and is applicable to solids, liquids and gases.
The Mackay method (Lyman 1985) was derived for two chemical classes: aliphatic and aromatic hydrocarbons and aliphatic and aromatic halogenated compounds. The suggested vapor pressure, for solids, is the modified Grain estimate and, for liquids and gases, is the average of the Antoine and modified Grain methods.
GLP compliance:
no
Type of method:
other: Calculation
Specific details on test material used for the study:
Chemical Name: Glycerol Esters of Maleated Rosin
CAS No.: 94581-16-5
EINECS No.: 305-515-7
EC name: Rosin acids and resin acids, maleated, esters with glycerol
IUPAC name: Esters of maleated rosin with glycerol
Batch No.: Not applicable
Purity: 100%
Appearance at room temperature: solid
Key result
Test no.:
#1
Vapour pressure:
0.227 Pa
Remarks on result:
other: QSAR calculation
Remarks:
QSAR calculation
Conclusions:
The scaled Vapor pressure results for the UVCB mix is 0.2273 Pa.
Executive summary:

The measurement of vapor pressure for the test material Glycerol Ester of Maleated Rosin was predicted using EPISuite v4.11[1](Estimation Program Interface), MPBPVP v1.43[2](Melting and boiling points, vapor pressure) (US EPA 2012). In the current approach, instead of providing the composition of glycerol esters of maleated rosin in a well determined sample, a composition range of mixtures typically observed in the laboratory was proposed to be more representative of the real-life situation.The scaled Vapor pressure results for the UVCB mix is 0.2273 Pa.

Description of key information

The measurement of vaporpressure for the test material Glycerol Ester of Maleated Rosin was predicted using EPISuite v4.11[1](Estimation Program Interface), MPBPVP v1.43[2](Melting and boiling points, vapor pressure) (US EPA 2012).

In the current approach, instead of providing the composition of glycerol esters of maleated rosin in a well determined sample, a composition range of mixtures typically observed in the laboratory was proposed to be more representative of the real-life situation.The scaled Vapor pressure results for the UVCB mix is 0.2273 Pa.

Key value for chemical safety assessment

Vapour pressure:
0.227 Pa

Additional information