What is Chlorotrimethylsilane CAS 75-77-4?

Chlorotrimethylsilane is an organosilicon silyl halide with CAS 75-77-4, EINECS 200-900-5 and molecular formula C₃H₉ClSi. It is a colorless to pale yellow, fuming liquid commonly called trimethylchlorosilane or TMCS.

What is Chlorotrimethylsilane used for?

It is used as a silylating agent to introduce trimethylsilyl protecting groups onto hydroxyl, carboxyl, amine and other reactive functional groups. It is also used in silicone fluid and silane synthesis, hydrophobic surface treatment and pharmaceutical intermediate production.

Are Chlorotrimethylsilane, TMCS and trimethylsilyl chloride the same product?

Yes. Chlorotrimethylsilane, trimethylchlorosilane, TMCS and trimethylsilyl chloride are common names for the same compound, CAS 75-77-4.

Why is Chlorotrimethylsilane moisture-sensitive?

The silicon-chlorine bond reacts readily with water and protic solvents, producing hydrogen chloride and silanol or siloxane byproducts. This is why it is used for silylation and why it must be protected from moisture during storage, transfer and reaction.

How should Chlorotrimethylsilane be stored and handled?

Store it in tightly sealed, corrosion-resistant containers under dry inert gas, away from water, moisture, alcohols, amines and strong bases. Use suitable ventilation and chemical-resistant PPE because contact with moisture can release hydrogen chloride.

Chlorotrimethylsilane CAS 75-77-4

Chlorotrimethylsilane (TMCS, trimethylchlorosilane), CAS 75-77-4, is a fuming organosilicon silylating agent used to introduce trimethylsilyl protecting groups, control silicone oil molecular weight and produce pharmaceutical intermediates and hydrophobic coatings. Confirm the required grade, then request a quotation with COA/TDS/SDS for bulk supply.

CAS: 75-77-4
Synonyms: TMCS, Trimethylchlorosilane, Trimethylsilyl chloride, Monochlorotrimethylsilicon
Einecs: 200-900-5
Molecular Formula: C₃H₉ClSi
Grade: Industrial grade 99%
Package: 200kg iron drum or 50kg plastic drum packing

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Product Description

Chlorotrimethylsilane, CAS 75-77-4, is trimethylchlorosilane (TMCS), an organosilicon silyl halide; the EC/EINECS number is 200-900-5.

Synonyms: TMCS; Trimethylchlorosilane; Trimethylsilyl chloride; Monochlorotrimethylsilicon.

CAS: 75-77-4.

Molecular formula: C₃H₉ClSi.

Molecular weight: 108.64.

EC number: 200-900-5.

It is a colorless to pale-yellow fuming liquid with a pungent odor; the melting point is about -40 °C, the boiling point about 57.3 °C and the density about 0.857 g/cm³.

It is highly flammable, with a flash point below -18 °C.

It reacts readily with water and protic solvents, releasing hydrogen chloride and forming silanol or siloxane byproducts.

It is produced by direct synthesis from methyl chloride and silicon.

It is used as a silylating agent to introduce trimethylsilyl protecting groups onto hydroxyl, carboxyl, amine and other functional groups.

It is used as an end-capping agent to control molecular weight in silicone oils, and in the synthesis of hexamethyldisiloxane and hexamethyldisilazane.

It is used for gas chromatography derivatization, hydrophobic surface treatment and pharmaceutical intermediate production.

Confirm assay, chlorides, water and color.

Store in tightly sealed, corrosion-resistant containers under dry inert gas, away from water, alcohols, amines and strong bases; use ventilation and chemical-resistant PPE.

Confirm the current product-specific specification.

Confirm packaging with the requested quantity and destination requirements.

Document requirements should be confirmed from the current specification, SDS, COA, or other product-specific files.

The page is an RFQ entry point and does not state stock, price, MOQ, or fixed lead time.

For an RFQ, state the intended use, required specification, quantity, packaging, destination, and document needs.

FAQ - Technical & Supply Chain

Q:
What is Chlorotrimethylsilane CAS 75-77-4?

A: Chlorotrimethylsilane is an organosilicon silyl halide with CAS 75-77-4, EINECS 200-900-5 and molecular formula C₃H₉ClSi. It is a colorless to pale yellow, fuming liquid commonly called trimethylchlorosilane or TMCS.
Q:
What is Chlorotrimethylsilane used for?

A: It is used as a silylating agent to introduce trimethylsilyl protecting groups onto hydroxyl, carboxyl, amine and other reactive functional groups. It is also used in silicone fluid and silane synthesis, hydrophobic surface treatment and pharmaceutical intermediate production.
Q:
Are Chlorotrimethylsilane, TMCS and trimethylsilyl chloride the same product?

A: Yes. Chlorotrimethylsilane, trimethylchlorosilane, TMCS and trimethylsilyl chloride are common names for the same compound, CAS 75-77-4.
Q:
Why is Chlorotrimethylsilane moisture-sensitive?

A: The silicon-chlorine bond reacts readily with water and protic solvents, producing hydrogen chloride and silanol or siloxane byproducts. This is why it is used for silylation and why it must be protected from moisture during storage, transfer and reaction.
Q:
How should Chlorotrimethylsilane be stored and handled?

A: Store it in tightly sealed, corrosion-resistant containers under dry inert gas, away from water, moisture, alcohols, amines and strong bases. Use suitable ventilation and chemical-resistant PPE because contact with moisture can release hydrogen chloride.

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