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Physical & Chemical properties

Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
calculation (if not (Q)SAR)
Remarks:
EPI Suite
Adequacy of study:
key study
Study period:
2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Not possible to isolate from water without decomposition
Qualifier:
no guideline followed
Version / remarks:
The model used is The Estimation Programs Interface (EPI) Suite developed by the US EPA and the Syracuse Organisation, using the following modules:
MPBPVP : melting point, boiling point and vapour pressure
Principles of method if other than guideline:
The substance is not possible to isolate from water and if attempted, there is decomposition with a loss of ammonia.
The substance is also functionally surface active, forming emulsions in water and oil
The vapour pressure cannot be easily assessed by normal methods, but can be put through computational modelling to confirm expert judgement that suggests low vapour pressure (ie not volatile for environmental or human health risk assessment) and to confirm that there is a low risk of accumulation
Note that due to limitations of the modelling, the ammonium salt was not possible to estimate, but instead the acid form was used
GLP compliance:
no
Type of method:
other: Modelling with EPI Suite
Specific details on test material used for the study:
Thetawet FS-8250 is a 28% actives aqueous emulsion, water dispersible, low foam anionic fluorosurfactant
The active components are ammonium salts of [Mono & Di] 2-(Perfluorohexyl)ethyl-Phosphate. Found at ca. 10% and 18% respectively in the final product
Key result
Test no.:
#1
Temp.:
25 °C
Vapour pressure:
>= 0.004 - <= 0.007 Pa

The vapour pressure of the individual components of the reaction mixture (Mono[2-(perfluorohexyl)ethyl] Phosphate and Bis[2-(perfluorohexyl)ethyl] Phosphate) were calculated separately.

These were reported as 0.0038 Pa for the mono species and 0.0078 Pa for the bis species.

Description of key information

The value given has been assessed using EPI Suite modelling for the ammonium bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) phosphate, which is the major component of the reaction mixture.

The substance is not possible to isolate from water and if attempted, there is decomposition with a loss of ammonia. 

The vapour pressure cannot be easily assessed by normal methods, but can be put through computational modelling to confirm expert judgement that suggests low vapour pressure (i.e. not volatile for environmental or human health risk assessment) and to confirm that there is a low risk of accumulation

Key value for chemical safety assessment

Vapour pressure:
0.007 Pa
at the temperature of:
25 °C

Additional information