chlorinate

Chlorinate is a verb meaning to introduce chlorine into a substance, typically by replacing a hydrogen atom with chlorine or by adding chlorine to a molecule. In chemistry, chlorination can be accomplished using elemental chlorine (Cl2), hydrogen chloride, hypochlorite reagents, or other chlorinating agents such as thionyl chloride (SOCl2), phosphorus pentachloride (PCl5), or sulfuryl chloride (SO2Cl2). The process is used in organic synthesis to form chlorinated derivatives and in water treatment to disinfect and preserve materials.

In organic synthesis, chlorination can be electrophilic (Cl2 adding to double bonds or aromatic rings with catalysts) or radical (chlorination of alkanes under light). Chlorinating agents such as N-chlorosuccinimide (NCS) enable selective chlorination at allylic or benzylic positions. Transformation of alcohols to alkyl chlorides occurs with reagents such as thionyl chloride, phosphorus pentachloride, or oxalyl chloride.

Industrial and public health applications include the production of organochlorines such as vinyl chloride for polyvinyl chloride (PVC), historically in solvents and refrigerants, and in water treatment where chlorine gas or hypochlorite is used to control biological contamination. Chlorination is also employed in pulp bleaching under controlled conditions.

Safety and environmental considerations are important: chlorine is highly toxic and corrosive, and chlorinated organic compounds can be persistent or form disinfection byproducts such as trihalomethanes when used in water treatment. Proper handling, containment, and waste management are required to minimize exposure and environmental impact.