Making Amines (Cambridge (CIE) AS Chemistry)

Production of Amines

• Amines are compounds with the amine (-NH₂) functional group 

• They can be produced as a result of nucleophilic substitution reactions of halogenoalkanes when they are heated under pressure with ethanolic ammonia (NH₃ in ethanol)

• The halogen atom in halogenoalkanes is more electronegative than the carbon atom it is bonded to

• The halogen, therefore, draws electron density from the C-X bond (where X is the halogen) towards itself

• The carbon, therefore, has a partial positive charge and the halogen itself has a partial negative charge  

• The lone pair of electrons on the nitrogen atom (in NH₃) acts as a nucleophile and attacks the partial positively charged carbon 

• As a result of this nucleophilic attack, the C-X bond is broken and the halogen is substituted by an amine group

Example nucleophilic substitution of a halogenoalkane 

Ammonia or amines replace the halogen in halogenoalkanes in a nucleophilic substitution reaction