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Physical & Chemical properties

Vapour pressure

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Description of key information

Vapour pressure (hexamethyldisiloxane): 5500 Pa at 25°C and approximately 4300 Pa at 20°C (OECD 104)

Key value for chemical safety assessment

Vapour pressure:
5 500 Pa
at the temperature of:
25 °C

Additional information

Measured vapour pressures of approximately 4300 Pa and 5500 Pa at 20°C and 25°C respectively were determined for the substance using a relevant test method but not in compliance with GLP. The result is considered to be reliable and selected as key study.

This value is supported by a vapour pressure of 4451 Pa at 20°C which was reported in a collection of reliable data which has been subject to peer-review and in which the original data sources are traceable. This supporting result is based on interpolation from a temperature-vapour pressure correlation. Similarly, in other reliable sources, vapour pressure values of 6375 Pa and 5320 Pa at 20°C and 24°C respectively were determined for the substance.

Several secondary sources to which reliability could not be assigned give vapour pressure values in the range 2500 - 6700 Pa at 20°C - 25°C. At the higher temperature of 50°C, a vapour pressure of 17300 - 17500 Pa was reported for the substance.

Variations in the vapour pressure values may be due to differences in the test method and the presence of impurities. All available values indicate that the substance is volatile.