What is Benzirline?
Benzirline is manufactured by heating together a mixture of nitrobenzene (produced by nitrating benzene, q.v.), zinc dust and aqueous caustic soda, preferably with addition of alcohol.
The colourless stage of the reduction being reached, the alcohol is distilled off, the hydrazobenzene is separated mechanically from zinc and zinc compounds, and dissolved in cold hydrochloric acid.
Addition of sodium sulphate to this acid solution precipitates sparingly soluble benzidine sulphate. This salt is suspended in water and decomposed with soda ash, the free benzidine being col lected, dried and purified by distillation under reduced pressure.