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Physical & Chemical properties

Vapour pressure

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Description of key information

Key result for CAS# 297730-93-9:
Vapour pressure at 20 °C: 0.847 kPa (6.35 mmHg) by a static method based on OECD TG104
Key result for PFBA (degradation product), CAS# 375-22-4:
Vapour pressure at 25 °C: 0.905 kPa (6.79 mmHg) by a dual ebulliometer technique equivalent to OECD104

Key value for chemical safety assessment

Additional information

Discussion for CAS# 297730-93-9:

Vapour pressure of CAS# 297730-93-9 was assessed in four studies. In the key study, CAS# 297730-93-9 had an extrapolated vapour pressure of 6.35 mm Hg (0.847 kPa) at 20°C using a static method at thermal equilibrium. The three remaining studies support this measurement. In the first supporting study, CAS# 297730-93-9 had an extrapolated vapour pressure of 6.7 mmHg (0.89 kPa) at 20° using a dynamic method. In the second supporting study, CAS# 297730-93-9 had a reported vapour pressure of 7.5 mmHg (1.0 kPa) at 20° C.  In the third supporting study, CAS# 297730-93-9 had a reported vapour pressure of 6 mmHg (0.8 kPa) at 20° C. The first two results are comparable, with the key study being the preferred value. 

 

The determination of the vapour pressure in the key study was based on EEC-Directive 92/69EEC, A.4 and on OECD Guideline no. 104, and was GLP-compliant. It is therefore considered reliable without restrictions, relevant and valid to this endpoint. It is not known whether the remaining studies were GLP compliant. However, the first supporting study used standard instrumentation according to method ASTM E-1719-97, in a dynamic method as permitted by TG104§8. It is therefore classified as reliable with restrictions. The second and third supporting studies are summary datapoints only, the reliability of which cannot be assessed.

Discussion for PFBA (degradation product), CAS# 375-22-4:

The vapour pressure of PFBA at 25 °C was determined by extrapolation of vapour pressures measured using a dual ebulliometer technique as part a large-scale effort to accurately and precisely determine thermodynamic characteristics of a variety of industrially-important chemicals. The methods used are equivalent to OECD104. The result has been compiled into peer-reviewed chemical information databases such as Beilstein, and the extrapolation is classified as reliable with restrictions. An additional boiling vapour pressure extrapolated to 25 °C of 0.979 kPa (7.34 mmHg), method not reported, is compiled into the Beilstein database. The key study was chosen based on better documentation and the quality of the method used.