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Environmental fate & pathways

Henry's Law constant

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Reference
Endpoint:
Henry's law constant
Type of information:
other: secondary source
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Calculated value stated in the EU RAR
Qualifier:
no guideline followed
Version / remarks:
A calculated Henry's Law constant value for acrylonitrile is stated in the EU RAR (2004)
Principles of method if other than guideline:
The EU RAR (2004) states a calculated Henry's Law constant value for acrylonitrile.
GLP compliance:
not specified
H:
9.6 Pa m³/mol
Conclusions:
Acrylonitrile can be regarded as a moderately volatile compound, based on the calculated Henry's Law constant of 9.6 Pa/m3/mol-1.
Executive summary:

Transfer of acrylonitrile from the aqueous to the atmospheric compartment can potentially arise as a consequence of volatilisation and air stripping from WWTP, given the relatively high vapour pressure of acrylonitrile. However this is counterbalanced by its high water solubility. Acrylonitrile can be regarded as a moderately volatile compound, based on the calculated Henry's Law constant of 9.6 Pa/m3/mol-1. There is little experimental evidence available to prove or disprove the possibility of volatilisation, and in practice direct transfer of acrylonitrile from water to air is likely to be minimal, particularly in WWTP where rates of biodegradation are likely to far exceed the potential volatilisation. This is supported by the results of Freeman and Schroy (1984) and Stover and Kincannon (1983).

Description of key information

The EU RAR reports a calculates value for Henry's Law constant of 9.6 Pa/m3/mol-1

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
9.6

Additional information

Acrylonitrile can be regarded as a moderately volatile compound, based on the calculated Henry's Law constant of 9.6 Pa/m3/mol-1.