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EC number: 213-650-7
CAS number: 998-30-1
Triethoxysilane is a liquid at standard temperature and pressure, with a
melting point of < -20°C and a measured boiling point of 132.5°C. It has
a measured relative density of 0.875 at 20°C, a predicted viscosity of
0.76 mPasat 25°Cand a measured
extrapolated vapour pressure of 921 Pa at 20°C.
The substance is classified as a highly flammable liquid on the basis of
a measured flash point of 19°C and the boiling point of 132.5°C. It has
a measured auto-ignition temperature of 237 - 240°C, and is not
explosive and not oxidising on the basis of chemical structure.
In contact with water, triethoxysilane is predicted to rapidly hydrolyse
(half-life of approximately 1 hour at 20 - 25°C and pH 7) to produce
silanetriol and ethanol according to the following equation:
HSi(OCH2CH3)3+ 3H2O → HSi(OH)3+
The Si-H bond may also be unstable, resulting in further hydrolysis toSi(OH)4.Silanols
may undergo condensation reactions to form siloxane dimers, oligomers
and polymers. In the case of triethoxysilane, where no organic
side-chains are present, rapid condensation to inorganic siloxanes and
finally silica is expected. The precise rate of this condensation and
the species present are dependent on conditions.
Therefore, requirements for testing of water-based physicochemical
properties for the substance are waived on the basis of instability in
water. The properties of the initial silanol hydrolysis products,
silanetriol and ethanol, are assessed instead.Ethanol is miscible
with water, has low log Kow(-0.3) and high vapour pressure
(7910 Pa at 25°C).Silanetriol has a predicted solubility in
water of 7.9E+05 mg/l at 20°C and has a low log Kow(-2.9,
predicted). It is not surface active and the volatility is expected to
be very low. It is not expected to undergo significant dissociation
within an environmentally-relevant range.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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