Basicity & Nucleophilicity
Chemistry: Cambridge International A Level, topic 3.7.2
Basicity and Nucleophilicity
Amines display both basic and nucleophilic behaviour. We also will look at quaternary ammonium salts.
Basicity
- Amines contain a lone pair of electrons. This makes the amine attracted to positive charge and, in particular, to protons.
- This gives them the basic property of being able to accept protons - as shown above.
Nucleophilicty
- The lone pair on the nitrogen also makes amines nucleophilic.
- It is attracted to positive charge.
- They react with halogenoalkanes, acyl chlorides and acid anhydrides in nucleophilic reactions.
Quaternary ammonium salts
- Quaternary ammonium salts can be used as cationic surfactants.
- Surfactants lower the surface tension of a liquid.
- They can act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.
- The cationic surfactant has a hydrophilic head, which is able to interact with water, and a hydrophobic tail, which interacts with organic matter such as oils or fats.