Registration Dossier

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Log Kow (1,1,1,3,3,3-hexamethyldisilazane): Not relevant
Log Kow (trimethylsilanol): 1.19 at 20°C (OECD 107)
Log Kow (ammonia): not relevant

Key value for chemical safety assessment

at the temperature of:
20 °C

Additional information

The requirement to conduct an n-octanol/water partition coefficient for the substance was waived because in contact with water, the substance hydrolyses very rapidly forming trimethylsilanol and ammonia.

The log Kow of the silanol hydrolysis product, trimethylsilanol was determined to be 1.19 at 20°C in accordance with OECD 107 and in compliance with GLP. This value is supported by another reliable log Kow of 1.22 at 25°C using an acceptable scientific method.

Log Kow is not applicable for the other hydrolysis product, ammonia, as it is inorganic. However, an indicative value of 0.23 has been predicted using the software KOWWIN (KOWWIN v1.68, US EPA, 2010) and this value is used in the exposure modelling. The value applies to unionised ammonia, NH3.