Tetraethyl silicate

Tetraethyl silicate (CAS 78-10-4), also known as TEOS or ethyl silicate, is a silicon alkoxide used as a reactive binder, crosslinker and silica precursor.

Where is Tetraethyl silicate used?

• Coatings: silicate binder in zinc-rich and inorganic coatings
• Construction: consolidates porous stone, concrete and masonry by penetrating the substrate
• Adhesives and sealants: crosslinking agent for thermal stability
• On hydrolysis it deposits amorphous silica, enabling surface treatments, protective coatings and ceramic structures without high-temperature sintering.
• Used in aerogel production.
• Largely used as a silicon source in the synthesis of silicon oxide for various optoelectronic applications.
• Used as a crosslinking agent for silicone polymers.

Good to know: Ethyl Silicate 40 offers higher silica content for specialised coating applications. Standard purity grades range from technical to high-purity electronic grade for semiconductor use.

Formulation notes

• Reacts with acids, water and oxidants.
• Slowly hydrolyzes to silicon dioxide and ethanol upon contact with ambient moisture.
• If a bubbler is used, the carrier gas must be moisture-free; otherwise polymerized products slowly accumulate in the reservoir, causing a decrease in vapor pressure and a shift in process characteristics.

Typical specification

• Color scale ≤20 APHA.
• SiO2 content 28% to 28.8%.

Regulatory status

• Assigned UN number 1292 for transport.
• UN classification: hazard class 3, packing group III.
• Classified as causing serious eye irritation (H319).
• EU OEL: 44 mg/m³, 5 ppm as TWA.

Storage, packaging and handling

• Should be kept away from moisture.
• Store fireproof, separated from acids and oxidants, cool, dry, and in a well-ventilated place.

Frequently asked questions about Tetraethyl silicate

What is the EU CLP harmonized classification index number for tetraethyl silicate?

The EU CLP harmonized classification index number is 014-005-00-0.

Which commercial grade of tetraethyl silicate is available at 99% purity?

Tetraethyl silicate is available as T 1400 (OTTO) with 99% purity, CAS 78-10-4.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.