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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Administrative data

Link to relevant study record(s)

Description of key information

The calculated HLC for the hydrolysis product methanol is 0.3 Pa.m3.mol-1 at 12°C

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
at the temperature of:
12 °C

Additional information

Tetramethyl orthosilicate hydrolyses rapidly (t1/2 = < 1 h at pH 7and 25°C) to (poly)silicic acid and methanol. (Poly)silicic acid is an inorganic substance with a negligible vapour pressure, which enters natural biogeochemical cycles for silicon. Therefore, volatilisation from water is not a relevant process. Methanol is expected to biodegrade fast. The HLC for ethanol can be estimated from the ratio of the vapour pressure (VP) to the water solubility (WS). HLC = (VP x MW)/WS where MW is molecular weight. The calculated HLC value for methanol at environmental temperature (12°C) is 0.3 Pa.m3.mol-1 (taken from EUSES 2.1.2). This indicates some potential to evaporate from water.