ClCH2OCH3

Chloromethyl methyl ether, with the chemical formula ClCH2OCH3, is an organic compound. It is a colorless liquid with a pungent odor and is volatile. The molecule consists of a methyl group (CH3) attached to an oxygen atom, which is then bonded to a chloromethyl group (CH2Cl). This structure makes it an ether and an alkyl halide.

Chloromethyl methyl ether is primarily used as a reagent in organic synthesis. It is often employed to introduce the methoxymethyl (MOM) protecting group onto alcohols, phenols, and sometimes amines. This protecting group is stable under a variety of reaction conditions and can be removed later in the synthesis. Its reactivity stems from the electrophilic nature of the chloromethyl carbon atom.

Due to its properties, chloromethyl methyl ether is considered a hazardous substance. It is a potent lachrymator, meaning it can cause severe eye irritation and tearing. It is also a suspected human carcinogen. Consequently, its handling requires strict safety precautions, including working in well-ventilated areas or fume hoods and using appropriate personal protective equipment. Its production and use are regulated in many jurisdictions.