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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Partition coefficient

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Administrative data

Link to relevant study record(s)

Description of key information

log Kow [1-(tert-butyldimethylsilyl)piperazine]: not relevant due to very rapid hydrolysis

log Kow [tert-butyldimethylsilanol]: 2.5 at 20°C (QSAR)

log Kow [piperazine]: -1.5

Key value for chemical safety assessment

Additional information

The requirement to conduct an n-octanol/water partition coefficient for the substance is waived because in contact with water, the substance hydrolyses very rapidly to form tert-butyldimethylsilanol and piperazine.

The log Kow of the silanol hydrolysis product, has been predicted to be 2.5 using a validated QSAR estimation method. A measured log Kow value of 2.7 at 25°C was determined for the silanol hydrolysis product in a study conducted according to an appropriate guideline and in compliance with GLP. However, the selected mobile phase constituents were unsuitable for organosilicon substances. Furthermore, an important corrective adjustment that is necessary for interpretation of HPLC data for organosilicon substances was not performed. This study is therefore disregarded.

Piperazine has a reported log Kow value of -1.5 (Hansch 1995).


Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 10