CLASSIFICATION OF HALOALKANES & HALOARENES

 

Haloalkanes

 

Haloalkanes

  • These have hydrocarbons made up with aliphatic alkanes and one or more hydrogen atoms replaced by halogens (elements such as Chlorine, Bromine, Fluorine, Iodine etc.).
  • Here, the halogen atom is attached to the sp3 hybridized carbon atom of the alkyl group.
  • Example: CH3Cl (Methyl Chloride)

                          CH3CH2Br (Ethyl Bromide)

  • These are saturated organic compounds where all the chemical bonds are attached to the carbon atom with single bonds and a single carbon atom is attached to the Halogen atom.
  • Haloalkanes are made by aliphatic alkanes by the process of free radical halogenation.
  • They are odourless compounds.
  • These precipitate in SN2 substitution reactions.


Haloarenes


  • Haloarenes are hydrocarbons consisting of aromatic ring/rings and one or more hydrogen atoms replaced by halogens.
  • The halogen atom is attached in the sp3 hybridized carbon atom of the alkyl group.
  • Example: Chlorobenzene, Bromobenzene.
  • They differ from Haloalkanes by their method of preparation and properties.
  • This compound is used for several purposes.
  • One of the most important Haloarene is aryl chloride.
  • Haloarenes are made by direct halogenation of aromatic rings.
  • They have a sweet odour.
  • These do not precipitate in SN2 substitution reactions.


Classification of Haloalkanes and Haloarenes


Classification of Haloalkanes and Haloarenes

Classification of Haloalkanes and Haloarenes

Haloalkanes and Haloarenes can be classified based on the following points:

  1. sp2 hybridized carbon halogen bond
  2. sp3 hybridized carbon halogen bond
  3. Number of halogen atoms on the molecule

Classification on the basis of sp2 hybridized carbon halogen bond:

  • Vinyl Halide- The halogen atom gets attached to the sp2 hybridized carbon C=C.
  • Aryl Halide- The halogen atom gets attached to the sp2 hybridized carbon in an aromatic ring.

Classification on the basis of sp3 hybridized carbon halogen bond:

  • Alkyl Halide- Halogen gets attached to the alkyl chain
  • Allylic Halide- The halogen atom gets attached to the sp3 hybridized carbon which is situated adjacent to the sp2 hybridized carbon C=C.
  • Benzylic Halide- The halogen atom gets attached to the sp3 hybridized carbon, attached to a benzene ring.

Classification on the basis of number of halogen atoms:

  • Mono Haloalkanes and Monohaloarenes- They contain one halogen atom.
  • Dihaloalkanes and Di-haloarenes- They contain two halogen atoms.
  • Tri Haloalkanes and Tri-haloarenes- They contain three halogen atoms.

Uses of Haloalkanes and Haloarenes

  • Used as solvents for non-polar compounds also known as hydrophobic compounds.
  • Used in the treatment of Malaria (Chloroquine).
  • Used for organic synthesis.
  • Used as insecticide
  • Some derivatives such as chloramphenicol are used for the treatment of typhoid.
  • Dichloro-Diphenyl-Trichloroethane or DDT is used in insecticides.

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