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Description of key information

Hydrolysis half-life (silazane group): Extremely rapid hydrolysis at 25°C (measured)

Key value for chemical safety assessment

Additional information

The silazane group is expected to hydrolyse very rapidly (instantaneously) in contact with water. This assumption is supported by a preliminary hydrolysis study conducted on the submission substance prior to the ready biodegradation study (Taruki 2014) using a method that is equivalent to a preliminary hydrolysis study according to OECD 111.

During the study, water was spiked with a known amount of the test substance and duplicate test solutions were prepared. The dilute test solutions were analysed using GC-FID; each sample was shaken, sampled and analysis was performed. Sampling of the test substance was performed at various time intervals of 0 hours (immediately after sample preparation), 0.5 hours, 1 hour and 1.5 hours. Sample analysis was performed immediately after preparation using GC-FID.

At t = 0 hours (immediately after sample preparation), t = 0.5 hours, t = 1 hour and t = 1.5 hours solutions, in the chromatograms of the sample solution taken, there were no peaks observed at the characteristic retention time of the test substance. No information on pH was stated; the test temperature is 25°C. The result indicates that the test substance undergoes very rapid hydrolysis when in contact with water. The study is considered to be reliable.


The hydrolysis products are tert-butyldimethylsilanol and piperazine.