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Description of key information

3-(Triethoxysilyl)propiononitrile is a liquid at standard temperature and pressure, with a melting point of -140.2°C at 1013 hPa and a boiling point of 224°C. It has a relative density of 0.97 at 20°C and a calculated vapour pressure of 1.9 Pa at 20°C.

The substance is not classified for flammability according to Regulation (EC) No. 1272/2008 on the basis of a measured flash point of 70.5°C at 1013 hPa and a boiling point of 224°C at 1013 hPa. The substance has a measured auto-ignition temperature of 254°C at 1013 hPa and it is not explosive and not oxidising on the basis of chemical structure.

In contact with water, the substance hydrolyses rapidly (half-lives of <0.5 h at pH 4 and pH 9, 6.5 h at pH 7 and 20°C) resulting in the formation of 3-(trihydroxysilyl)propiononitrile (CAS 182156-21-4) and ethanol according to the following equation:

N=CCH2CH2Si(OCH2CH3)3+ 3H2O ¿ N=CCH2CH2Si(OH)3 + 3CH3CH2OH

Therefore, requirements for testing of water-based physicochemical properties for the substance are waived on the basis of instability in water.

However, the properties of the parent submission substance have been estimated using appropriate QSAR methods. The substance has a predicted log Kow value of 1.7 and a predicted water solubility value of 4E+03 mg/L at 20°C.

Ethanol is miscible with water, has low log Kow (-0.3) and high vapour pressure (7910 Pa at 25°C).

The saturation concentration in water of the silanol hydrolysis product, 3-(trihydroxysilyl)propiononitrile, is limited by condensation reactions to approximately 1000 mg/L. However, it is very hydrophilic (calculated solubility is 1.0E+06 mg/L using a QSAR method) and has a predicted log Kow of -2.9. 3-(Trihydroxysilyl)propiononitrile is not surface active and is much less volatile than the parent substance with a predicted vapour pressure of 6.7E-05 Pa at 25°C.

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