Problems and exercisesReactivity

1. Products

Write the main product of each reaction:

1. Phenol + aqueous NaOH
2. Phenol + NaOH, then CH₃CH₂Br
3. Phenol + acetic anhydride in pyridine
4. Phenol + excess bromine water
5. Phenol + dilute HNO₃ at 20 °C
6. Hydroquinone + Na₂Cr₂O₇, H₂SO₄

2. Cleaving an ether

Which products are obtained when anisole (methoxybenzene) is heated with excess HI? Why is iodobenzene not formed?

3. More reactive than benzene

Explain why phenol is brominated without a catalyst whereas benzene needs FeBr₃. Why does bromine enter ortho and para?

4. Separating the nitrophenols

Nitration of phenol gives a mixture of 2-nitrophenol and 4-nitrophenol. Which one distils in steam and why?

5. From phenol to aspirin

Give the sequence leading from phenol to aspirin and the name of each reaction.

6. Antioxidants

Why is BHT (2,6-di-tert-butyl-4-methylphenol) a good antioxidant?