Amines

Question 1

Types of amines

Answer 1

Primary- one alkyl/aryl group on N
Secondary- two alkyl/aryl groups on N
Tertiary- three alkyl/aryl groups on N
Quaternary- four alkyl/aryl groups on N forming a salt

Question 2

Preparation of primary amines

Answer 2

Halogenoalkane + ammonia
Heat with excess ammonia in ethanol in sealed flask

Reduction of nitriles
Hydrogen in presence of nickel catalyst

Question 3

Preparation of aromatic amines

Answer 3

Reduction of nitrogen compounds
RNO2 + 6[H] -> RNH2 + 2H2O
Heatbunder reflux with tin and excess HCl adding NaOH ( due to ion formed)

Used in dyes

Question 4

Basic properties of amines

Answer 4

Weak bases
Accept protons
Amine + acid -> alkyl ammonium salt

Question 5

Comparison of base strength

Answer 5

Aromatic amine < ammonia < aliphatic amine
Aliphatic are strongest bases due to alkyl group electron donating effect, lone pair is more available
Aromatic are weakest bases due to lone pair overlapping pi electrons in benzene ring so lone pair less available

Question 6

Creating higher level amines

Answer 6

Each level is a better nucleophile due to lone pair becoming more available
Excess ammonia favours production of primary amines
Excess halogenoalkane favours quaternary ammonium salts

Question 7

Uses of quaternary ammonium salts

Answer 7

Cationic surfactant found in detergents, fabric softeners and hair conditioners
Coat surface of cloth or hair with positive charges to reduce static