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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Dimethylbis(octadecyloxy)silane is a low melting-point solid at standard temperature and pressure, with a melting point of 32°C and a measured boiling point of 407°C. It has a measured relative density of 0.889 at 20°C and measured vapour pressure values of 4E-04 Pa at 20°C and 0.023 Pa at 50°C.

The substance is not classified for flammability according to Regulation EC (No.) 1272/2008 on the basis of a measured flash point of 199.5°C and a boiling point of 407°C. It has a measured auto-ignition temperature of 353°C at 963 -969 hPa, and is not explosive and not oxidising on the basis of chemical structure.

 

Dimethylbis(octadecyloxy)silane reacts with water (predicted half-life of >15 hours) to form dimethylsilanediol (1 mole) and 1-octadecanol (2 moles) according to the following equation:

 

 (CH3)2Si(O(CH2)17CH3)2+ 2H2O → (CH3)2Si(OH)+ 2CH3(CH2)16CH2OH

 

Dimethylbis(octadecyloxy)silane has a predicted water solubility of 2.5E-14 mg/l at 20-25°C, and a predicted log Kow of 9.0 at 25°C. Given the very high adsorption potential and very low water solubility hydrolysis is likely to be very slow in the environment and in vivo.