Amines

Question 1

Explain the basicity of amines

Answer 1

Amines are weak bases. It has a lone pair of electrons on the nitrogen atom and can accept a proton.

Question 2

Describe the base reactions of amines

Answer 2

base + acid –> salt

Question 3

how do you prepare aliphatic amines?

Answer 3

nucleophillic substitution, warming halogenoalkanes with an excess of ammonia. Ethanol is the solvent.

Question 4

how do you prepare aromatic amines?

Answer 4

nitroarenes (such as nitrobenze) are reduced by using a mixture of tin and conc HCl. aromatic arenes are formed as products in the reaction.

Question 5

what are the two steps in the preparation of azodyes?

Answer 5

• diozatisation

- coupling reactions

Question 6

describe the first step in preparing azodyes

Answer 6

DIAZOTISATION

• Nitrous acid (NO2) is generated by reacting together sodium nitrate (NaNO2) and excess HCl
• cold NO2 then reacts with an aromatic amine (eg phenylamine) to form a diazonium salt.

Question 7

describe the second step in preparing azodyes

Answer 7

COUPLING

- diazonium salt, benzendiazonium chloride, reacts with an aromatic compound UNDER ALKALINE CONDITIONS

Question 8

Give a balanced equation for the formation of a diazonium ion

Answer 8

NaNO2 + HCl -> HNO2 + NaCl