Silicones & Silicates
REACH
Tetrabutyl orthosilicate
CAS Number
4766-57-8
EC Number
225-305-8
What is Tetrabutyl orthosilicate?
Tetrabutyl orthosilicate (CAS 4766-57-8), also known as tetrabutyl silicate, is a reactive alkoxysilane used as a crosslinker and surface modifier.
Where is Tetrabutyl orthosilicate used?
- Protective coatings and sealants: crosslinking agent
- Construction: stone and concrete consolidant
- Silicone elastomers: curing agent and chain extender
- Adhesives: improves substrate wetting and promotes chemical bonding at interfaces
- It hydrolyzes under moisture to form silica networks, enabling durable bonding and surface consolidation.
Good to know: Controlled hydrolysis reinforces porous surfaces without altering appearance.
Commercial specifications
- Purity typically 97–99%
- Packaging from drums to IBC containers, with bulk supply
Other Names (Synonyms)
Tetrabutyl silicate|Tetra-n-butoxysilane|Silane, tetrabutoxy-|Silicon tetrabutoxide|Silicic acid (H4SiO4), tetrabutyl ester|Butyl silicate ((BuO)4Si)|TETRABUTYL ETHYLDINEBISPHENOL
What are the physical properties of Tetrabutyl orthosilicate?
Melting Point <-80 °C
Boiling Point 115 °C @ Press: 3 Torr
Density 0.899 g/cm³
Flash Point 174 °F
Appearance Colorless transparent liquid
Color colorless
Form liquid
Water Solubility reacts
Refractive Index n 20/D 1.413(lit.)
How is Tetrabutyl orthosilicate classified and handled safely? Learn More
Warning
GHS07· Irritant
Hazard Statements
H315 Causes skin irritation
H319 Causes serious eye irritation
H335 May cause respiratory irritation
Precautionary Statements
P261 Avoid breathing dust/fume/gas/mist/vapours/spray.
P264 Wash … thoroughly after handling.
P271 Use only outdoors or in a well-ventilated area.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
Which trade and regulatory codes apply to Tetrabutyl orthosilicate?
HS Code 29209090
UN Number 2924
Storage Class 10 - Combustible liquids
WGK (Germany) 3