What is the halogenation of alkenes?

When a bromine molecule approaches the area of unsaturation in an alkene, the covalent molecule becomes polarized and can act as an electrophile, resulting in the formation of the dibromoalkane. Bromine tests for unsaturation in alkenes through an electrophilic addition reaction.

The halogenation of alkenes is a reaction in which a halogen (such as chlorine or bromine) adds across the carbon-carbon double bond of an alkene to form a dihalide product. This reaction is typically carried out in the presence of a halogen carrier or catalyst, such as elemental bromine (Br2) or chlorine (Cl2), which helps facilitate the addition of the halogen to the alkene. The reaction proceeds through a mechanism known as electrophilic addition, where the π electrons of the alkene act as a nucleophile and attack the electrophilic halogen molecule. This results in the formation of a cyclic halonium ion intermediate, which is then opened by a nucleophile (such as a halide ion or water) to yield the final dihalide product.