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[3-(2,3-Epoxypropoxy)propyl]triethoxysilane is a liquid at standard temperature and pressure, with a measured melting point of <-70°C at 1013 hPa and a predicted boiling point of 270°C at 1013 hPa. It has a predicted density of 0.97 g/cm3 at 20°C, a predicted vapour pressure of 0.07 Pa at 25°C and a predicted kinematic viscosity of 2.3 mm2/s at 20°C.

The substance is soluble in water based on predicted water solubility of 3300 mg/L at 20°C and a predicted log Kow of 2.0.

The substance is not classified for flammability according to Regulation EC (No) 1272/2008 on the basis of a measured flash point of 119°C at 1013 hPa and a predicted boiling point of 270°C at 1013 hPa. It has a measured auto-ignition temperature of 230°C at 1002.1-1019.8 hPa and is not oxidising on the basis of chemical structure. The substance is found not to be explosive based on read-across from related structural analogue, [3-(2,3-epoxypropoxy)propyl]trimethoxysilane using EU Method A.14 test method; the presence of an epoxy group in an organosilicon compound is not associated with explosive properties.

In contact with water, [3-(2,3-epoxypropoxy)propyl]triethoxysilane reacts moderately rapidly (half-life of 12–36 hours at pH 7 and 25°C) to ultimately produce 2,3-dihydroxypropoxypropylsilanetriol and ethanol according to the following equation:


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

The saturation concentration in water of the silanol hydrolysis product, 2,3-dihydroxypropoxypropylsilanetriol is limited by condensation reactions that can occur over time at loadings about 1000 mg/L. However, it is very hydrophilic (calculated solubility is 1.0E+6 mg/L at 20°C using a QSAR method) and has a low log Kow of -3.8 (predicted).

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. 2,3-Dihydroxypropoxypropylsilanetriol is much less volatile than the parent substance with a predicted vapour pressure of 1.7E-07 Pa at 25°C and it is not surface active.

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