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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

(3-Chloropropyl)triethoxysilane (CAS 5089-70-3, EC No. 225-805-6) is a liquid at standard temperature and pressure, with a measured freezing point of <-20°C at 1013 hPa, and a measured boiling point of 221°C at 1071 hPa. It has a predicted density of 1.03 g/cm3 at 20°C, a predicted kinematic viscosity of 1.6 mm2/s at 20°C and a measured vapour pressure of 30.9 Pa at 25°C.

The substance is not classified for flammability according to Regulation (EC) No. 1272/2008 on the basis of a measured flash point of 99°C at 1013 hPa and a measured boiling point of 221°C at 1013 hPa. It has a measured auto-ignition temperature of 231°C at 1013 hPa and it is not explosive and not oxidising on the basis of chemical structure.

In contact with water, the substance hydrolyses moderately rapidly (half-lives of <0.4 h at pH 4 at 20°C, 35 h at pH 7 and 2 h at pH 9 and 25°C) resulting in the formation of (3-chloropropyl)silanetriol (CAS 64426-41-4) and ethanol (CAS 64-17-5, EC No. 200-578-6) according to the following equation:

Cl(CH2)3Si(OCH2CH3)3 + 3H2O ¿ Cl(CH2)3Si(OH)+ 3CH2CH3OH


The properties of the parent submission substance have been determined using relevant methods. The substance has a measured log Kow value of 3.13 at 21°C and pH 7.02-7.61, it has a measured water solubility value of approximately 113 mg/L at 20°C and pH 4.7.

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-chloropropyl)silanetriol, is limited by condensation reactions to approximately 1000 mg/L. However, it is very hydrophilic (calculated solubility is 1.0E+06 mg/L using a QSAR method) and it has a predicted log Kow of -1.1. (3-Chloropropyl)silanetriol is not surface active and is much less volatile than the parent substance, with a predicted vapour pressure of 2.5E-04 Pa at 25°C. The first dissociation constant of a structurally analogous silanetriol (phenylsilanetriol) has been reported to be around pKa of 10.

Additional information