Registration Dossier

Physical & Chemical properties

Vapour pressure

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

WoE approach based on 4 data from handbooks. The values are from 2.9 to 4 Pa. In a conservative approach we will retain the value of 4Pa.

Key value for chemical safety assessment

Vapour pressure:
4 Pa
at the temperature of:
20 °C

Additional information

Data from four handbooks provide vapour pressures of 2.9 to 4 Pa at 20°C to 25°C. Two sources do not mention the physical form or the concentration (Vp of 4Pa). In two sources the physical form was reported, in the first one it was reported to be a 101% aqueous solution and in the second one it was reported to be 100% clear cristal (Vp 3Pa).

Some additonnal supporting sources provide data as:

- aqueous partial vapour pressure of H2O vapor at 25°C to be <133 Pa for an aqueous solution of concentration >90%.

- Vapor pressures of different acids with variable content of P4O10 at elevated temperature

- water activity over phosphoric acid

- A test was launched in 2010 ( Holzschuh, 2010) in order to determine vapour pressure of the solid phosphoric acid (100%), nevertheless due to corrosive and hydroscopic properties of the substance, the test was quite difficult to perform. Additionnally only an estimation of the vapour pressure could be obtained, it was determined that the vapour pressure of phosphoric acid as supercooled liquid at 25°C is under 0.8 mbar (80Pa). Due to the sensitivity of the method, 20 mbar +/- 10 mbar, the order of magnitude of the value is questionable.