Are Tetraethyl Orthosilicate, Tetraethoxysilane and Ethyl Silicate the same product?

These names are commonly used for tetraethyl orthosilicate, CAS 78-10-4, also called tetraethoxysilane or TEOS. It should not be confused with partially hydrolyzed ethyl silicate grades such as ethyl silicate 40, which contain oligomeric silica species and different silica content. State whether monomeric TEOS or a pre-hydrolyzed grade is required.

What is TEOS mainly used for?

TEOS is a moisture-sensitive silicon alkoxide used as a silica precursor in sol-gel processing, aerogels, thin films, nanoparticles, mesoporous silica and SiO2-based materials. Industrial uses also include precision investment-casting binders, inorganic zinc-rich coatings, crosslinking in sealants and silicone polymers, and selected glass, ceramic and protective-coating applications.

Which specifications are most important for industrial TEOS?

Confirm TEOS assay by GC, water, acidity, colour, density, hydrolysable chloride, nonvolatile residue and oligomer or pre-hydrolyzed ethyl-silicate content. Sol-gel, foundry-binder and coating users can require different hydrolysis profiles, so the test methods and limits should be tied to the intended process.

What physical properties should be confirmed for the offered grade?

Confirm a clear, colourless liquid appearance, boiling range of about 165-169 degrees C at atmospheric pressure and density of about 0.93-0.94 g/cm3 near 20 degrees C. TEOS is flammable, with reported closed-cup flash points commonly around 45-54 degrees C, so flash-point and vapour-handling controls should be checked for the offered grade.

Why is moisture control critical for TEOS?

TEOS hydrolyzes in the presence of water, first forming silanol and ethanol and then condensing into silica networks. Uncontrolled moisture can cause cloudiness, gelation or precipitation and can change silica content and reactivity. Dry, sealed containers and inert-gas blanketing where required help preserve the original grade.

How should TEOS be stored and handled?

Store in compatible, tightly sealed packaging in a cool, dry, well-ventilated flammable-liquid storage area away from water, moisture, strong acids, alkalis and oxidizers. Use grounding and vapour controls during transfer, avoid static accumulation, and use suitable ventilation and PPE because TEOS is irritating to the eyes and respiratory tract.

Tetraethyl Orthosilicate (TEOS) CAS 78-10-4

Tetraethyl Orthosilicate, CAS 78-10-4, for sol-gel silica, foundry binders, coatings and grade-specific silane processes. Before requesting a quotation, confirm assay, water content, acidity, colour, hydrolysable chloride or other relevant impurities, packaging and intended process, and request current TDS, COA and SDS.

CAS: 78-10-4
Synonyms: Tetraethyl orthosilicate; Tetraethoxysilane; Tetraethyl silicate; Ethyl silicate; TEOS
Einecs: 201-083-8
Molecular Formula: C₈H₂₀O₄Si
Grade: Confirm on the offered specification and lot COA: assay, water content, acidity, colour, hydrolysable chloride or other relevant impurities, packaging and intended process.
Package: Compatible sealed packaging; confirm configuration for quantity, transport mode, destination and grade requirements

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Product Description

Product name: Tetraethyl Orthosilicate (TEOS)

Recognized names: Tetraethyl orthosilicate; Tetraethoxysilane; Tetraethyl silicate; Ethyl silicate; TEOS

Formula: C₈H₂₀O₄Si

Molar mass: 208.33 g/mol

CAS Number: 78-10-4; EC Number: 201-083-8

Appearance: clear, colourless liquid; confirm colour, assay, water and acidity on the offered specification.

Melting point: published reference values vary with material and method; confirm the current TDS and SDS for the offered grade.

Boiling point: about 165-169 °C at atmospheric pressure; confirm the test conditions in the current TDS.

Density: about 0.93-0.94 g/cm³ near 20 °C; confirm the offered grade and test method.

TEOS as a Silica Precursor

Industrial use: hydrolysable silica precursor for sol-gel processing, foundry and precision-casting binders, inorganic zinc-rich coatings and selected silane processes. High-purity, electronic or fixed-silica-content suitability requires a separate grade specification.

FAQ - Technical & Supply Chain

Q:
Are Tetraethyl Orthosilicate, Tetraethoxysilane and Ethyl Silicate the same product?

A: These names are commonly used for tetraethyl orthosilicate, CAS 78-10-4, also called tetraethoxysilane or TEOS. It should not be confused with partially hydrolyzed ethyl silicate grades such as ethyl silicate 40, which contain oligomeric silica species and different silica content. State whether monomeric TEOS or a pre-hydrolyzed grade is required.
Q:
What is TEOS mainly used for?

A: TEOS is a moisture-sensitive silicon alkoxide used as a silica precursor in sol-gel processing, aerogels, thin films, nanoparticles, mesoporous silica and SiO2-based materials. Industrial uses also include precision investment-casting binders, inorganic zinc-rich coatings, crosslinking in sealants and silicone polymers, and selected glass, ceramic and protective-coating applications.
Q:
Which specifications are most important for industrial TEOS?

A: Confirm TEOS assay by GC, water, acidity, colour, density, hydrolysable chloride, nonvolatile residue and oligomer or pre-hydrolyzed ethyl-silicate content. Sol-gel, foundry-binder and coating users can require different hydrolysis profiles, so the test methods and limits should be tied to the intended process.
Q:
What physical properties should be confirmed for the offered grade?

A: Confirm a clear, colourless liquid appearance, boiling range of about 165-169 degrees C at atmospheric pressure and density of about 0.93-0.94 g/cm3 near 20 degrees C. TEOS is flammable, with reported closed-cup flash points commonly around 45-54 degrees C, so flash-point and vapour-handling controls should be checked for the offered grade.
Q:
Why is moisture control critical for TEOS?

A: TEOS hydrolyzes in the presence of water, first forming silanol and ethanol and then condensing into silica networks. Uncontrolled moisture can cause cloudiness, gelation or precipitation and can change silica content and reactivity. Dry, sealed containers and inert-gas blanketing where required help preserve the original grade.
Q:
How should TEOS be stored and handled?

A: Store in compatible, tightly sealed packaging in a cool, dry, well-ventilated flammable-liquid storage area away from water, moisture, strong acids, alkalis and oxidizers. Use grounding and vapour controls during transfer, avoid static accumulation, and use suitable ventilation and PPE because TEOS is irritating to the eyes and respiratory tract.

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