Registration Dossier
Registration Dossier
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EC number: 201-083-8 | CAS number: 78-10-4
Endpoint summary
Administrative data
Description of key information
Additional information
Tetraethyl orthosilicate (CAS 78-10-4; EC No. 201-083-8) hydrolyses rapidly (t1/2 = 4.4 h at pH 7 and 25°C) in contact with water to form monosilicic acid (CAS 10193-36-6; EC No. 233-477-0) and ethanol (CAS 64-17-5; EC No. 200-578-6).
Ethanol is readily biodegradable and has a low log Kow value.
Monosilicic acid is a naturally occurring substance which is not harmful to aquatic organisms and will be incorporated into solid inorganic matrices such as silica.
In addition, monosilicic acid is known to be the major bioavailable form of silica for aquatic organisms and plays an important role in the biogeochemical cycle of silicon. Most living organisms contain at least trace quantities of silicon. For some species silicon is an essential element taken up actively. For example, diatoms, radiolarians, flagellates, sponges and gastropods all have silicate skeletal structures. The potential releases of inorganic silicon resulting from use of tetraethyl orthosilicate are negligible compared to the natural flux of silica in the environment.
Silicic acid is therefore not considered in the environmental exposure assessment (Section 9).
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