Structure, Properties, Application and Development Prospect of Chlorotrimethylsilane (HC-ZM3068)

Apr. 18, 2025

In the molecule of trimethylchlorosilane, silicon atoms are connected with three methyl groups and one chlorine atom by a single bond, which is in an approximate tetrahedral configuration, with a bond angle close to 109.5°, and it is a kind of important organosilicon compounds with a wide range of application values in many fields.

I. Products

Chemical name: Chlorotrimethylsilane

Alias: Trimethylsilyl chloride/Trimethyl chloride

English name: chlorotrimethylsilane

Molecular Formula:C3H9ClSi

Molecular weight: 108.64

CAS:75-77-4

Corresponding foreign grades:

provider	grades
Amresco/Sigma, USA	KLC104814(≥99.0% GC), KLC104813(>98.0% GC)

Well-known foreign manufacturers:

provider	grades	note
Evonik Industries	No specific license plate number	Evonik is one of the world's leading suppliers of silicone chemicals.
Dow Chemical	Dow Brand Products	Offers a wide range of silicone chemicals which includes trimethylchlorosilane.
Shin-Etsu Chemical	Brand name not disclosed	A well-known Japanese silicone manufacturer with reliable product quality.
Wacker Chemie	GENIOSIL Series	Covers a wide range of silane products, including chlorotrimethylsilane.
Gelest	Products dedicated to the field of specialty chemicals and materials	Provides laboratory and industrial scale silicone products.
Alfa Aesar	No specific license plate number	Mainly used in the laboratory chemical reagent market, high purity
Carl Roth	PEPTIPURE® ≥99%	Mainly used for gas chromatography (GC) and other applications where high purity is required.

As an important member of organosilicon chemistry, trimethylchlorosilane has unique chemical properties and wide application value. It can not only be used for the preparation of various organosilicon compounds and organosilicon materials, but also can be used as a reaction reagent to participate in a variety of organic synthesis reactions, and has been occupying an important position in industrial production and scientific research.

In recent years, with the continuous progress of science and technology and the in-depth development of various fields, its application fields are also expanding and innovating.

Physical and chemical indicators:

Indicator	typical value
Appearance and odor	Colorless transparent liquid with irritating odor
Density (25°C, g/cm3)	0.854
Boiling point ℃	57
Refractive index (nD25)	1.500
solubility	Soluble in organic solvents such as ethanol and ether, but insoluble in water. Reacts with water to form hydrogen chloride and trimethylsilanol.

II. Principles of reaction:

Trimethylchlorosilane has a reactive chlorine atom on the silicon atom and is therefore able to participate in a wide range of reactions in organic synthesis, especially nucleophilic substitution and condensation reactions.

Nucleophilic substitution: The silicon-chlorine bond in trimethylchlorosilane makes the chlorine atom a good leaving group due to its high polarity. In the presence of nucleophilic reagents (e.g. water or alcohols), the silicon atom is susceptible to attack by nucleophilic reagents, resulting in nucleophilic substitution reactions.

Example:

Ø reacts with water to form trimethylsilanol ((CH3)3SiOH);

Ø Reacts with alcohol to form trimethylsilyl ether ((CH3)3SiOR).

These types of reactions are used in organic synthesis for the introduction (e.g., hydroxyl- or amino-protection) and removal of protecting groups, and play an important role especially in multistep synthesis.

Condensation reaction: Due to its high reactivity, the silicon-chlorine bond in trimethylchlorosilane can condense with a variety of compounds containing hydroxyl or amine groups to produce silicon-oxygen or silicon-nitrogen bonds, and this type of condensation reaction is an important way to prepare silicon-based functional materials.

Example:

Condensation with hydroxyl compounds for applications in the synthesis of siloxane polymers and functionalized silicone ether compounds.

Example: Reaction with diols or polyols to form siloxane chains or cross-linked siloxides:

(CH3)3SiCl+HO-R-OH→(CH3)3Si-O-R-O-Si(CH3)3+2HCl

Condensation with amine compounds, used in the preparation of silicone-based catalysts, drug intermediates and specialty chemicals. Example: Reaction with amine compounds to form trimethylsilylamine ((CH3)3Si-NR2):

(CH3)3SiCl+R-NH2→(CH3)3Si-NHR+HCl

Condensation (cross-linking reaction) with polyhydroxy compounds to form reticulated silicone-oxygen polymers used in products such as synthetic coatings, adhesives, silicones and water repellents.

Condensation with anhydrides or esters produces silyl ester compounds, which are used in the synthesis of specialty silane reagents.

(CH3)3SiCl+CH3COO-R→(CH3)3Si-OCOCH3+R-Cl

Condensation reactions are an important type of reaction for trimethylchlorosilanes, especially in the preparation of silicon oxides, silicon nitrides and organosilicon functionalized derivatives. These reactions are widely used in organic synthesis, materials science, pharmaceutical development and industrial catalysis.

Halogen exchange: Trimethylchlorosilane can be halogen exchanged with other halogenated compounds to produce other trimethyl halosilanes (e.g. (CH3)3SiF): (CH3)3SiCl+KF→(CH3)3SiF+KCl

Protective group introduction: Trimethylchlorosilane is often used as a protective group to protect functional groups such as alcohols and phenols from being interfered with in subsequent reactions through the formation of silyl ether bonds.

Catalytic coupling: Under the action of catalysts (such as platinum, palladium and other noble metal catalysts or certain organometallic catalysts), trimethylchlorosilane can react with other silanes or organic compounds in a coupling reaction, generating new organosilicone compounds through the breaking and formation of chemical bonds. This type of reaction has important application value in organosilicon chemistry and material science, and can be used to prepare a variety of organosilicon materials with special properties.

Grignard reaction: Trimethylchlorosilane can also be reacted with Grignard reagents (e.g. R-MgX, where R is a hydrocarbon group and X is a halogen). In this process, the silyl group (i.e., trimethylsilyl) is transferred to produce the corresponding trimethylsilyl compound and by-products such as magnesium chloride. This type of reaction usually needs to be carried out under anhydrous and oxygen-free conditions to avoid side reactions. By reacting with Grignard reagents, trimethylchlorosilane can introduce specific hydrocarbon groups, thus further enriching the variety of organosilicon compounds and application areas.

Ⅱ. Wide range of application areas:

Chemical industry: Trimethylchlorosilane is mainly used as raw material and intermediate of organic synthesis in chemical industry to prepare many kinds of organosilicon compounds and silanized derivatives. For example, hexamethyldisiloxane (silicone ether), hexamethyldisilazane, trimethylcyanosilane, silicone oil, polysilicone, methyl silicone oil capping agent and so on. In addition, it can be applied in the field of polysilicon preparation.

The molecular structure of trimethylchlorosilane contains three outwardly extending methyl groups, and this structural feature enables it to be used as a capping agent to regulate and control the molecular weight of polymers during the synthesis of organosilicon polymers. Especially in the production of silicone oil, it can effectively regulate the molecular weight and performance of silicone oil by reacting with the active groups at the end of the silicone oil molecular chain to form a stable capping structure. Trimethylchlorosilane has a wide range of applications as capping agent .