ClCH2COCl

ClCH2COCl, commonly known as chloroacetyl chloride, is an organochlorine compound and an acyl chloride with the chemical formula C2H2Cl2O. It is used as a reactive acylating agent in organic synthesis to install the 2-chloroacetyl group onto amines, alcohols, or other nucleophiles.

Structure and properties: Chloroacetyl chloride is a colorless to pale yellow, highly volatile liquid with a pungent odor. It is moisture sensitive and reacts vigorously with water, producing chloroacetic acid and hydrogen chloride. It also reacts with alcohols and amines to form esters and amides, respectively. Due to its reactive acyl chloride functionality, it is typically handled under strictly dry conditions and in a fume hood.

Preparation: A common route to chloroacetyl chloride is the conversion of chloroacetic acid to its acid chloride using reagents such as thionyl chloride or oxalyl chloride, releasing sulfur dioxide and hydrogen chloride.

Reactions and applications: As an acylating agent, chloroacetyl chloride enables introduction of the 2-chloroacetyl moiety. With amines, it forms N-(2-chloroacetyl)amides; with alcohols, it yields 2-chloroacetyl esters. It is employed as an intermediate in the preparation of pharmaceuticals, agrochemicals, and other organic synthesis building blocks requiring the chloroacetyl functionality.

Safety: Chloroacetyl chloride is corrosive, lachrymatory, and reacts violently with water. It can cause severe burns on skin and eye contact and releases HCl upon hydrolysis. Handle with appropriate PPE in a well-ventilated fume hood, store in a dry, tightly closed container away from moisture and bases.