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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Water solubility

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water solubility
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Principles of method if other than guideline:
Equilibration by slow-stirring (pure liquid substance in contact with distilled water).
GLP compliance:
Type of method:
other: Equilibration by slow-stirring
Water solubility:
0.056 mg/L
23 °C
ca. 7
Details on results:
Stable: no
Degradation products: yes
Degradation products (CAS No./EC No./EINECS Name): 1066-42-8 213-915-7 dimethylsilanediol

Water solubility = 56.2 ug L-1  (190 x 10-9 mol L-1) at 23 °C

Interpretation of results: insoluble (< 0.1 mg/L)
A water solubility value of 0.0562 mg/L was determined at 23°C in a reliable study conducted according to generally accepted scientific principles.

Description of key information

Water solubility [octamethylcyclotetrasiloxane]: 0.056 mg/l at 23°C

Key value for chemical safety assessment

Water solubility:
0.056 mg/L
at the temperature of:
23 °C

Additional information

Two reliable measured values for the solubility of the registration substance in freshwater are available. A water solubility value of 0.056 mg/l at 23°C was determined for the substance using equilibration by the slow-stirring method. The result is considered to be reliable and is selected as key study. This value is supported by a measure water solubility of 0.07 mg/l at 25°C using a relevant test method. The key study was selected as it is the most recent study and is in line with the UK RAR. In a secondary source to which reliability could not be assigned, a water solubility of 0.02 mg/l at 25°C was reported for the substance.

In synthetic seawater, the substance has a measured solubility of 0.033 mg/l at 25°C.