It is obtained by the oxidation of orthophenylene diamine with ferric chloride; when a mixture of para-aminodimethylaniline and meta-toluylenediamine is oxidized in the cold, toluylene blue, an indamine, being formed as an intermediate product and passing into the red when boiled; and also by the oxidation of dimethylparaphenylene diamine with metatoluylene diamine.
Paraphenylene diamine may be prepared as above, and also by the reduction of amidoazobenzene.
Witt (Ber., 1877, 10, p. 656), is obtained by coupling phenyl diazonium chloride with meta-phenylene diamine.
The polymer is produced by the elimination of hydrogen chloride from terephthaloyl chloride and para-phenylene diamine.
When heated with hydriodic acid (specific gravity 1.96) it forms amino-acetic acid, and with tin and hydrochloric acid it yields ethylene diamine.