(A Level) Amines, phenylamine and azo dyes

Learning objectives

Describe the preparation of primary and secondary amines from halogenoalkanes with ammonia or an amine in ethanol under pressure, and by reducing amides or nitriles with LiAlH₄ (or nitriles with H₂/Ni)

Explain the basicity of aqueous amines and the order of basicity of ethylamine, ammonia and phenylamine from the availability of the nitrogen lone pair

Outline the two-stage route from benzene to phenylamine (nitration, then reduction of nitrobenzene by tin and concentrated HCl under reflux with NaOH(aq) added to free the amine), and describe phenylamine's reaction with bromine water

Describe how benzenediazonium chloride is made from phenylamine with NaNO₂ and dilute HCl, explaining why it must be kept below 10 °C, and how it couples with phenol in alkaline solution to give an azo dye containing the –N=N– group