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Physical & Chemical properties

Vapour pressure

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Description of key information

The vapour pressure of the test material was estimated at 0.000971 Pa and 0.00391 at 25°C and 35°C, respectively.

Key value for chemical safety assessment

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

Additional information

 

Obtaining an experimental vapor pressure value for DETDA is technically complicated because of trace levels of impurities. The ECHA guidance Chapter R.7A states "[t]he major cause of inaccurate vapour pressure measurements is due to the presence of impurities in the sample which have a higher vapour pressure than that of the major components." Though an experimental measure is available (Featherstone and Rutland, 2010), the investigators used the dynamic method for measuring vapour pressure. This method is not suitable for substances with vapour pressures below 1 Pa. These data should only, however, be used for screening DETDA's vapor pressure and identifying it as less than 1 Pa, but they should not be relied upon as a confirmed value. Given that the greatest difficulty and uncertainty arises with obtaining reliable measures for vapour pressure on substances with low volatility (i.e., vapour pressure < 1 Pa), the ECHA have recommend estimation methods under Chapter R.7A for determining this endpoint. Of the methods listed, the ECHA found that the SPARC software provides estimates with the lowest mean absolute error; therefore, the vapour pressure generated using SPARC was selected.