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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Adsorption / desorption

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Administrative data

Link to relevant study record(s)

adsorption / desorption: screening
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the physicochemical properties of the substance indicate that it can be expected to have a low potential for adsorption

Description of key information

Adsorption/desorption: Low potential for adsorption

Key value for chemical safety assessment

Additional information

Testing is waived in accordance with Column 2 of REACH Annex IX. The substance has a predicted log Kow value of 1.4 and thus has low potential for adsorption.

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 also has low potential for adsorption due to its low log Kow.

Monosilicic acid exists only in dilute aqueous solutions and readily condenses at concentrations above approximately 100-150 mg/L as SiO2 to give a dynamic equilibrium between monomer, oligomers and insoluble amorphous polysilicic acid. These hydrolysis products are inorganic substances which enter natural biogeochemical cycles; adsorption/desorption studies are not relevant. Based on their structure, the hydrolysis products will have a high affinity for water and a low affinity for organic carbon and so a low potential for adsorption to the organic carbon. However, they may interact with the mineral content of soil. Amorphous polysilicic acid is a constituent of most soils.