Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 249-385-9 | CAS number: 29043-70-7
Hydrolysis
Administrative data
Link to relevant study record(s)
Description of key information
Hydrolysis half-life [dimethylbis(octadecyloxy)silane: >15 h at pH 7, >0.5 h at pH 4 and >0.2 h at pH 9 and 20-25°C (QSAR).
Key value for chemical safety assessment
- Half-life for hydrolysis:
- 15 h
- at the temperature of:
- 20 °C
Additional information
It is not technically feasible to carry out a hydrolysis study for dimethylbis(octadecyloxy)silane owing to its very low water solubility. Hydrolysis half-life values at 20-25°C of >0.5 h at pH 4, >15 h at pH 7 and >0.2 h at pH 9 and 20-25°C were obtained using an accepted calculation method.
The registered substance has a very high adsorption potential (log Kow value of 9) and very low water solubility (2.5E-14 mg/L at 20 °C); hydrolysis is therefore likely to be very slow in the environment and in vivo. The products of hydrolysis are dimethylsilanediol and octadecan-1-ol.
Hydrolysis of the read-across substance trimethyl(octadecyloxy)silane (CAS 18748 -98 -6)
Data for the substance trimethyl(octadecyloxy)silane (CAS 18748-98-6) are read-across to the submission substance dimethylbis(octadecyloxy)silane for appropriate endpoints. The requirement to conduct a hydrolysis study was waived in accordance with Column 2 of REACH Annex VIII because the substance is highly insoluble in water. The hydrolysis half-life for trimethyl(octadecyloxy)silane is predicted to be approximately 15 hours at pH 7 using an appropriate QSAR. The products of hydrolysis are trimethylsilanol and octadecan-1 -ol.
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.
