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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

The substance, 3-(triethoxysilyl)propanethiol, CAS 14814-09-6; EC No. 238-883-1 is a liquid at standard temperature and pressure, with a glass transition temperature of -141°C at 1013 hPa and a measured boiling point of 236°C at 1013 hPa. It has a measured relative density of 0.983 at 20°C and a predicted vapour pressure of 2.9 Pa at 25°C.


3-(Triethoxysilyl)propanethiol has a predicted water solubility value of 82 mg/L at 20°C and a measured log Kow of 2.7 at 20°C and pH 7.6 -7.7.


The substance is not classified for flammability according to Regulation (EC) No. 1272/2008 on the basis of a measured flash point of 89.5°C at 1013 hPa and a measured boiling point of 236°C at 1013 hPa. It has a measured auto-ignition temperature of 205°C at 998-1011 hPa and is not explosive and not oxidising on the basis of structural examination.


In contact with water, 3-(triethoxysilyl)propanethiol reacts moderately rapidly (half-life of 0.0533 hours at pH 4, 32.1 hours at pH 7, 4.69 hours at pH 9 and 20°C) to produce 3-(trihydroxysilyl)propanethiol and ethanol, CAS 64-17-5; EC No. 200-578-6 according to the following equation:




Due to the moderate hydrolysis of 3-(triethoxysilyl)propanethiol in contact with water, the key physicochemical properties of the hydrolysis products are presented below.


Ethanol is miscible with water, has low log Kow (-0.3) and high vapour pressure (7910 Pa at 25°C).


The saturation concentration in water of the silanol hydrolysis product, 3-(trihydroxysilyl)propanethiol, is limited by condensation reactions that can occur over time at loadings above approximately 1000 mg/L. However, it is very hydrophilic (calculated solubility is 1.0E+06 mg/L at 20°C using a QSAR method) and has a low log Kow (-1.4, predicted). It is not expected to be surface active and it is much less volatile than the parent substance with a predicted vapour pressure of 1.1E-04 Pa at 25°C. The silanol hydrolysis product is not expected to undergo significant dissociation within the environmentally-relevant range. The first dissociation constant of a structurally analogous silanetriol (phenylsilanetriol) has been reported to be around pKa of 10. Similarly, the thiol group has a calculated pKa of approximately 10.






Additional information