4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane

Endpoint summary

Description of key information

4,4,7,7-Tetraethoxy-3,8-dioxa-4,7-disiladecane is a liquid at standard temperature and pressure, with a measured melting point of -34°C and a measured boiling point of 267.7°C. It has a measured relative density of 0.966 at 20°C and a measured vapour pressure values of 0.3 Pa at 20°C and 6.3 Pa at 50°C.

 

The substance is not classified as a flammable liquid according to Regulation (EC) No. 1272/2008 on the basis of a measured flash point of 116.5°C and a measured boiling point of 267.7°C. It has a measured auto-ignition temperature of 228°C at 969 -979 hPa and is not explosive and not oxidising on the basis of structural examination.

 

In contact with water, 4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane reacts moderately (half-life of 36 hours at pH 7, 0.8 hours at pH 4, 0.7 hours at pH 5 and 0.5 hours at pH 9 and 20-25°C) to produce 1,1,1,4,4,4-hexahydroxy-1,4-silabutane and ethanol according to the following equation:

C₁₄H₃₄O₆Si₂+ 6H₂O → C₂H₁₀O₆Si₂ + 6C₂H₆O

 

The key physicochemical properties of the parent submission substance have been predicted using a validated QSAR estimation method. 4,4,7,7 -Tetraethoxy-3,8-dioxa-4,7-disiladecane has a predicted log K_ow value of 2.7 at 20°C and predicted water solubility value of 20 mg/L at 20°C.

The saturation concentration in water of the silanol hydrolysis product, 1,1,1,4,4,4-hexahydroxy-1,4-silabutane, is limited by condensation reactions to approximately 100-500 mg/l. However, it is very hydrophilic (calculated solubility is 1E+06 mg/l at 20°C using a QSAR method), has a predicted log K_ow value of -4.0 and it has a predicted vapour pressure of 4.4E-0.8 Pa at 25°C.

Ethanol has a reported log K_ow of -0.3, vapour pressure of 7910 Pa at 25°C and is miscible with water.