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Physical & Chemical properties

Vapour pressure

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Description of key information

Vapour pressure [Tripotassium propylsilanetriolate in aqueous solution]: not necessary

Vapour pressure: 4.6E-03 Pa, 1.5E-06 Pa and 1.3E-09 Pa at 25°C for propylsilanetriol, and dimer and trimer of propylsilanetriol respectively. (QSAR)

Key value for chemical safety assessment

Additional information

The requirement to test tripotassium propylsilanetriolate for vapour pressure is waived because the substance is only stable in aqueous solution and, therefore, the test is scientifically unjustified.

At pH 7 and low concentration (conditions relevant for the environment), the monomer (propylsilanetriol) will predominate. Therefore, a vapour pressure of 4.6E-03 Pa at 25°C was predicted for propylsilanetriol using a validated QSAR estimation method.

Similarly, under certain conditions such as high concentration, the dimer and trimer of propylsilanetriol may be formed in solution. Vapour pressure values of 1.5E-06 Pa and 1.3E-09 Pa at 25°C were predicted for the dimer and trimer of propylsilanetriol respectively using a validated QSAR estimation.

The vapour pressure of the silanolate salts is expected to be negligible.