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Physical & Chemical properties

Vapour pressure

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Description of key information

The vapour pressure of the test item has been determined experimentally to be 1.0 Pa at 25ºC.
The estimated vapour pressure for the main esters of the test substance ranged from 2.74 x 10-9 Pa to 7.81 x 10-8 Pa at 25°C.

Key value for chemical safety assessment

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

Additional information

Vapour Pressure.

1.0 Pa at 25°C, using the vapour pressure balance method, designed to be compatible with Method A4 Vapour Pressure of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 104 of the OECD Guidelines for Testing of Chemicals, 23 March 2006. 

A slight, but gradual drop in vapour pressure was observed on repeated temperature cycling of the test item over the range 5 to 15°C (under vacuum), with individual values in the range 1.0 to 3.7 x 10-1 Pa at 25°C for nine consecutive runs. Such characteristics are indicative of the gradual reduction of a more volatile fraction. To provide representative data for risk assessment on accidental release of the test item, the initial, highest value obtained has been taken as the definitive result.

A maximum vapour pressure of 1 Pa was observed in an experimental study. This is believed to be attributable to residual water and ethylene glycol present in the test item and is not reflective of the vapour pressure of the substance.

The vapour pressure of each main phosphate ester (listed below) was therefore derived using a computer program EPISuite 2003.

- 2-(bis(2-hydroxyethyl)amino)ethyl dihydrogen phosphate, sodium salt (1:?)

- ((2-hydroxyethyl)azanediyl)bis(ethane-2,1-diyl) bis(dihydrogen phosphate), sodium salt (1:?)

- nitrilotris(ethane-2,1-diyl) tris(dihydrogen phosphate), sodium salt (1:?)

The estimated vapour pressure for the main esters ranged from 2.74 x 10-9 Pa to 7.81 x 10-8 Pa at 25°C.

This data indicates that the vapour pressure of the substance is substantially lower that 1 Pa established in the experimental study.

Based on this data the vapour pressure of the substance is estimated to be 2.74 x 10-9 Pa to 7.81 x 10-8 Pa at 25°C