Amines Flashcards
Are amines strong or weak bases?
Weak bases
Explain the basicity of amines
A base is a proton acceptor and amines have a lone pair of electrons on the nitrogen atom and can accept a proton.
Therefore they are bases.
Difference between aliphatic and aromatic arenes in terms of structure
Aromatic arenes are rings and aliphatic arenes are straight chains.
How are aliphatic amines prepared?
Warming halogenoalkanes gently with an excess of ammonia, using ethanol as a solvent.
How do we prepare a primary amine and minimise further substitution?
By using an excess of ammonia
What are the conditions for the preparation of aromatic amines?
- Tin and conc HCl as a reducing agent
- heat under reflux
What is the product of the reduction of nitroarenes?
Phenylamine and water
How are aromatic amines produced?
Through the reduction of nitroarenes using tin and conc HCl together as the reducing agent and heating under reflux
What is the general equation for the preparation of aromatic amines?
ArNO2 + 6[H] -> ArNH2 + 2H2O
Where Ar stands for arene
What are the two stages of synthesis of dyes from phenylamine?
- Diazotisation
2. Coupling reactions
What is diazotisation?
Mixing phenylamine and nitrous acid below 10C to form a diazonium salt.
What is coupling?
Reacting a diazonium salt with a phenol under alkaline conditions.
What is the azo functional group?
-N=N-
What kind of compound does coupling produce?
A brightly coloured one
