Aromatic Chemistry

Question 1

What are the problems with the kekulé structure?

Answer 1

• Benzene rarely undergoes addition reactions so must be more stable than the kekule structure.
• The shape of benzene would be irregular due to the difference size of bonds but actually the bonds in benzene have a regular bond length between c=c and c-c.
• Real benzene is more stable, which is evidenced by the hydrogenation being 152kJmol-1 less than it should be.

Question 2

How is the electrophile NO2+ produced?

Answer 2

H₂SO₄ + HNO₃ —> H₂NO₃⁺ + HSO₄⁻

H₂NO₂⁺ + H₂SO₄ —> NO₂⁺ + H₃O⁺ + HSO₄⁻

Question 3

What is ethanoyl chloride reacted with to produce the electrophile?

Answer 3

AlCl₃

Question 4

How is acyl chloride produced?

Answer 4

React PCl5 with a carboxylic acid

Question 5

What are uses of aromatic compounds formed from nitration?

Answer 5

explosives, dyes.

Question 6

How can an acyl be produced from a benzene compound?

Answer 6

Friedel-crafts acylation –mechanism with acyl electrophile

Question 7

How is the electrophile for friedel-crafts acylation produced?

Answer 7

By reacting an acyl chloride with AlCl3

Question 8

why is AlCl3 classed as a catalyst in friedel-crafts acylaton?

Answer 8

The H+ produced at the end of the mechanism reacts with the extra chlorine, producing AlCl3 and HCl

Question 9

What mechanism do benzene compounds undergo?

Answer 9

electrophilic substitution

Question 10

How is phenolamine produced from nitrobenzene?

Answer 10

Add tin and concentrated HCl with heat, then add NaOH Solution.