Halogenation Reaction

Halogenation is a chemical reaction where one or more hydrogen atoms are replaced by halogen groups. If we look at the order of reactivity of halogen compounds, they are found as fluorine > chlorine > bromine > iodine, where fluorine is more reactive than all others. At the same time, being more aggressive, it also participates in more reactions with organic materials. At the same time, it also helps in making the organohalogens the most stable. If we make a fluorine atom react with it, then it can prove to be very difficult to separate it. 

Similarly, it is very difficult to make iodine iodo organic, where iodine has to react with organic molecules. But iodine can be easily removed after the reaction. Along with this we also get to see the electronegativity of the halogen atom, which acts as a driving force during the halogen reactions. During this, the nature of the molecule also plays a major role in completing the reaction. There are several types of halogenation depending on the substrate, where saturated hydrocarbons and unsaturated organic halogenation reactions occur.

C6H6  + Cl2  →   C6H5Cl + HCl

Why are halogen reactions important?

Chemical synthesis is very important for the halogen reaction, the products produced through the halogen reaction are used in many places, in which industries such as pharmaceuticals, polymers and plastics, refrigerants, fuel additives, fire retardants, agricultural products are the main Elements like fluorine or chlorine are used for better treatment in main areas like medicine. It also plays a major role in the production of compounds such as organic bromides and organodines.

As a substrate, chemistry has proven useful in many fields, helping to improve functional groups and providing the basis for complex chemical reactions. This alcohol helps to be hydrolyzed during the reaction, where it helps to form C–Cl or C–Br bonds. It is useful for oxidation reactions, where it helps form ketones, aldehydes, and acids.

It is also essential for elimination reactions, where double bonds form. Bromination of organic compounds during chemical reactions often helps to form Grignard reagents. At the same time it also aids in alkylation of rings, which are mainly needed during the Friedel Crafts reaction, where alkyl halides are used as reagents. In addition, it plays a major role in converting fluoroethylene to chlorodifluoromethane.

Types of Halogenation Reaction

The halogenation reaction can be carried out both organically and inorganically, where the substrate provides the main basis, here the methods of halogenation are described, which are as follows;

• Free radical system with saturated hydrocarbons
• like an unsaturated creature
• like electrophilic substitution

Free Radical Halogenation or Halogen Substitution- Saturated hydrocarbons mainly use hydrogen atoms, where the hydrogen atoms are replaced by halogens during the reaction. Here the relative weakness of the C–H bond is observed in the reaction, where the halogen regiochemistry of alkanes is determined in this reaction. During this, the reaction is carried out with the alkene to produce alkyl halides, where heat is the main contributor. The main use of this reaction is in the production of chlorinated methane in industries.

CH4 + Cl2 → CH3Cl + HCl

Halogen Addition Reaction- Unsaturated carbon is the main part of this reaction, where the reaction of alkenes and alkynes is seen. Here the halonium ions play a major role in the formation of products in the reaction, where halogens are reacted with alkanes. Here we can see chlorine reacting with ethylene.

Halogen Substitution – This reaction occurs mainly with saturated hydrocarbons, where halogen atoms replace hydrogen atoms during the reaction. Also the free radical halogens present here are commonly used for the treatment of hydrocarbons, with halogens saturated hydrocarbons can usually be seen, which form C–H bonds during the reaction of alkanes with halogens.

 In the example given here, we will discover one thing. We generate alkyl halides when we react halogens with alkanes, although the influence of heat is most noticeable in this reaction.

CH3CH3  +  Cl2   →   CH3CH2Cl + HCl

CH4  + Br2     →  CH3Br  + HBr

Here we will see various reactions in the presence of Lewis acids (FeCl3 or AlCl3), the main examples being substitution processes or electrophilic halogenation.

C6H5 – H  + Cl2 → C6H5 – Cl + HCl

Electrophilic Substitution Reaction- Electrophilic substitution process, mainly using aromatic halogen compounds, with bromine and chlorine participating as major participants. Lewis acid is used to carry out this reaction.

2Fe + 3Cl2  → 2FeCl3

2Fe + 3Br2  → 2FeBr3

Examples

Depending on the reactivity of the halogens,  F2 > Cl2 > Br2 > I2 can be described, with related examples as follows;

Reaction with Chlorine- The interaction of chlorine with benzene yields chlorobenzene, which is generally carried out in the presence of iron or aluminium chloride. Chlorination is slowed considerably by the presence of oxygen.

C6H6  + Cl2 → C6H5 – Cl + HCl

Reaction with Fluorine – The interaction of  fluorine with benzene yields fluorobenzene, which is generally carried out in the presence of iron or aluminium chloride..

C6H5 -NO2 + F2 → C6H4 – F- NH2

Conclusion

Halogen reactions are of great importance primarily in synthetic chemistry, as well as provide great support in industries such as polymers and plastics, refrigerants, fire retardants, fuel additives, agricultural products, etc. In addition, it is the main contributor to the polymerase reaction. It is also necessary in making PV or in the production of dichloroethane.