Nitrogen compounds

Question 1

Synthesis of amines/phenylamines

Answer 1

1. Nucleo sub of RX
2. Reduction of amides
3. Reduction of nitriles
   $. Reduction of nitrobenzene to phenylamine (ONLY WAY!)

Question 2

R&C for nucleo sub of RX

Answer 2

Mono-sub: Excess NH3 in ethanol, heat in sealed tube

Question 3

R&C for reduction of amides to amines

Answer 3

LiAlH4 in dry ether

Question 4

R&C for reduction of nitriles to amines

Answer 4

LiAlH4 in dry ether OR H2, Ni, heat

Question 5

Reactions of amines/ phenylamines

Answer 5

1. Condensation of amines to amides
2. Acid-base reaction
3. Phenylamines: Electo-sub

Question 5

Distinguishing test for phenylamines

Answer 5

Electro-sub
Observations:
1. Orange Br2 decolourises
2. White ppt of 2.4.6-tribromophenylamine formed
3. White fumes of HBr

Question 5

R&C for nitrobenzene to phenylamine

Answer 5

1. Sn, conc HCl. heat under reflux
2. NaOH (aq)

Question 6

R&C for acid-base rxn for amines

Answer 6

HCl(aq)
* All amines are lewis bases

Question 7

R&C for condensation of amines to amides

Answer 7

anhydrous acyl chloride, rtp

Question 8

Why are phenylamines more reactive towards electrosub than phenols?

Answer 8

1. N is less EN than O
2. LP of electrons on N delocalises into benzene ring to a larger extent than LP of electrons on O
3. Benzene in phenylamine more electron rich than in phenol
4. Phenylamines more reactive

Question 9

Synthesis of amides

Answer 9

1. Condensation of amines to amides (ONLY ONE WAY)

Question 10

Reactions of amides

Answer 10

1. Hydrolysis
2. Reduction

Question 11

Explain the basicity of nitrogen compounds

Answer 11

• electron-donating –> electron density on N increases –> LP of electrons more available for donation –> Strong base

Question 12

R&C for hydrolysis of amides and products

Answer 12

Acidic Hydrolysis:
R&C: H2SO4, heat
Basic Hydrolysis:
R&C: NaOH, heat