Mechanism of Halogenation
Mechanism of halogenation takes place in two types,
- Radical Halogenation Mechanism
- Electrophilic Addition in Alkene Halogenation
Let’s learn about them in detail.
Radical Halogenation Mechanism
Mechanism of free radical halogenation involves a chain reaction that proceeds through three steps: initiation, propagation, and termination.
- Initiation: In the initiation step, the halogen molecule splits into two radicals upon heating or irradiation, forming a couple of free radicals.
- Propagation: In the propagation step, the free radical reacts with the organic compound, forming a new radical and a halogenated product. The new radical reacts with another halogen molecule, forming another halogenated product and regenerating the original free radical.
- Termination: In the termination step, two free radicals combine to form a non-radical product, terminating the chain reaction.
Halogenating agent is usually a halogen molecule, such as chlorine or bromine, which splits into two radicals upon heating, forming a couple of free radicals. The reactivity of the halogens in this reaction follows the order F2 > Cl2 > Br2 > I2, with fluorine being the most reactive and iodine being the least reactive. The halogenation of alkanes is an essential example of radical halogenation.
Electrophilic Addition in Alkene Halogenation
Electrophilic addition in alkene halogenation is a reaction where halogens, such as bromine or chlorine, act as electrophiles and attack the double bond of an alkene. The reaction proceeds through a two-step mechanism: the first step involves the formation of a cyclic intermediate, while the second step involves the attack of a halide ion on the intermediate to form the halogenated alkane.
Reaction is stereospecific and produces vicinal dihalides with anti-addition. The reaction is typically carried out in an inert solvent, such as CCl4, and requires a halogen molecule, such as Br2 or Cl2, as the halogenating agent. The reactivity of the halogens in this reaction follows the order F2 > Cl2 > Br2 > I2, with fluorine being too vigorous and explosive and iodine being too slow due to the size of its atom. The halogenation of ethylene with Br2 is a common example of electrophilic addition in alkene halogenation.
Halogenation
Halogenation is a chemical process that involves adding halogen atoms into compounds. This reaction is common in organic chemistry and has diverse applications, from making drugs to flame retardants.
In this article, we will discuss about Definition of Halogenation, Types of Halogenation Reactions, Examples, and Others in detail.
Table of Content
- What is Halogenation?
- Types of Halogenation Reactions
- Mechanism of Halogenation
- Halogenation of Different Organic Compounds
- Factors Affecting Halogenation
- Applications of Halogenation
Contact Us