Amines

• What are amines produced from?

  Amines are produced when one or more hydrogen atoms in ammonia are replaced with an organic group.
• How are amines classified?

  Amines can be classified as primary (1°), secondary (2°), or tertiary (3°) based on how many hydrogen atoms are replaced.

  
• What are the two main methods for producing amines?

  1. Nucleophilic Substitution

  • Reaction of halogenoalkane with ammonia

  1. Reduction of Nitriles

  • Hydrogenation of nitriles using LiAlH4 or hydrogen with Nickel

  
• What is produced when one mole of halogenoalkane reacts with two moles of ammonia?

  A primary amine and an ammonium salt are produced.

  
• What happens in the nucleophilic substitution reaction of amines?

  The substitution can continue until all hydrogen atoms are replaced with organic groups, leading to a quaternary ammonium salt.

  
• Why does the reaction of halogenoalkanes with ammonia have low efficiency?

  Because a mixture of products is produced due to multiple possible substitutions.
• How can you achieve only the primary amine in the nucleophilic substitution reaction?

  By adding ammonia in excess.
• What is required for the reduction of nitriles to produce amines?

  LiAlH4 as a reducing agent and acidic conditions or hydrogen with Nickel.

  
• How can aromatic amines be produced?

  From the reduction of nitrobenzene using concentrated hydrochloric acid and a tin catalyst.

  
• What are cationic surfactants and their properties?

  • Complexes with a positive and negative end
  • Good conditioners
  • Prevent static from building up on surfaces
  • Useful in industry
• Why are amines considered weak bases?

  Because the lone electron pair on the nitrogen atom can accept protons.

  
• What affects the base strength of amines?

  The availability of the lone electron pair on the molecule.

  
• How do benzene rings affect the basicity of amines?

  Benzene rings draw electron density away from the nitrogen, making it less available.

  
• How do alkyl groups influence the basicity of amines?

  Alkyl groups push electron density towards the nitrogen, making it more available.

  
• What is the difference in basicity between aliphatic and aromatic amines?

  • Aliphatic amines are stronger bases.
  • Aromatic amines are weaker bases.
• How do amines act as nucleophiles?

  The lone electron pair is attracted to ∂+ regions on other molecules.
• What can amines substitute in nucleophilic substitution reactions?

  Amines can substitute halides on halogenoalkanes.
• What are the products of nucleophilic addition-elimination reactions involving amines?

  • Amides
  • N-substituted amides
• What other compounds can amines react with in nucleophilic addition-elimination reactions?

  Amines can react with acyl chlorides and acid anhydrides.
• How are n-substituted amides named?

  They are treated in a similar way to esters.