organochlorides

Organochlorides are organic compounds that contain one or more carbon–chlorine bonds. They encompass a broad range of structures, including alkyl chlorides (haloalkanes), aryl chlorides, vinyl chlorides, and more highly chlorinated hydrocarbons. The C–Cl bond is typically polar, and the physical properties vary from gases to dense liquids. Alkyl chlorides tend to undergo nucleophilic substitution readily, whereas vinyl and many aryl chlorides are less reactive due to the partial double-bond character of the C–C framework.

Common examples include chloromethane (CH3Cl), dichloromethane (CH2Cl2), chloroform (CHCl3), carbon tetrachloride (CCl4), vinyl chloride (CH2=CHCl), and chlorobenzene (C6H5Cl). They are used as solvents (dichloromethane, chloroform), intermediates in organic synthesis, and monomers for polymers such as polyvinyl chloride (PVC) from vinyl chloride. Some organochlorides have been used as refrigerants, pesticides, and flame retardants, and a variety of chlorinated compounds serve as dielectric fluids in electrical equipment.

Preparation generally proceeds by chlorination of hydrocarbons or by converting alcohols or alkenes to chlorinated derivatives using chlorinating reagents. For example, free-radical chlorination of methane yields chloromethane and higher chlorinated methanes; alcohols can be converted to chlorides with reagents such as thionyl chloride.

Health and environmental considerations are important for organochlorides. Many are toxic or carcinogenic, and some are persistent and bioaccumulative. Some chlorinated substances have contributed to ozone depletion and are heavily regulated, along with certain pesticides and industrial solvents.