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Physical & Chemical properties

Vapour pressure

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Description of key information

=< 7.7 Pa at 20 °C

Key value for chemical safety assessment

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

Additional information

The vapour pressure of the substance was determined with the use of Grain-Watson estimation as outlined in the OECD Guideline 104. The experimental result of the vapour pressure measurement using the DSC method was not in the appropriate validity range with respect to this method and it was discarded.

The Grain-Watson calculation is based on the lowest possible boiling temperature, which in fact is probably a decomposition temperature. In a peer reviewed SIDS Initial Assessment Profile for alkyl sulphates (structurally related to alcohols ethoxylated, sulphated; SIAM 25, 17 -18 October, 2007) it is stated that: "As ionic substances, all members of this category have extremely low vapour pressures. Calculated values are in the ranges 1E-11 hPa to 1E-15 hPa (C8 -18 alkyl sulphates) (...) Therefore, they decompose before reaching their theoretical boiling points". Thus, the obtained value should be considered an upper limit of the vapour pressure and accepted for the risk assessment calculations in the sense of a "worst-case scenario".