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Aromatic compounds, carbonyls and acids

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Question 4

A student reacts methylbenzene with a mixture of concentrated nitric acid and concentrated sulfuric acid at 100°C to form impure crystals of an organic compound, D.

a.

Describe how the student could recrystallise the impure crystals to obtain a pure sample of D.

[4]
b.

The pure sample of D is analysed to give the following results:

  • Percentage composition by mass: C\text{C}C, 37.01%; H\text{H}H, 2.22%; N\text{N}N, 18.50%; O\text{O}O, 42.27%.
  • The mass spectrum of D shows a molecular ion peak at m/z=227.0m/z = 227.0m/z=227.0.
  • The 13C^{13}\text{C}13C NMR spectrum of D shows a total of 5 peaks: four peaks in the aromatic region (120–150 ppm) and one peak in the aliphatic region (15–25 ppm).

The table below shows directing effects for different groups in the electrophilic substitution of aromatic compounds.

Directing effect2- and 4-directing3-directing
Group−OH-\text{OH}−OH, −CH3-\text{CH}_3−CH3​, −NH2-\text{NH}_2−NH2​−NO2-\text{NO}_2−NO2​

Analyse all the information to suggest the structure for D. Show all your reasoning.

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Aromatic compounds, carbonyls and acids Questions

  1. A Level
  2. /Chemistry
  3. /Aromatic compounds, carbonyls and acids