Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

2,4,6,8-Tetramethylcyclotetrasiloxane hydrolyses rapidly. The half-life for the initial ring-opening has been determined to be 2.2 min (0.037 h) at pH 7 and 22.5oC. This gives a half-life of ca. 0.085 h at pH 7 and 12oC using the conversion DT50 (XoC) = DT50 (t) x e(0.08(T-X))(ECHA Guidance R16). The rate constant, k, is then ln2 / 0.085 = 8.2 h-1.