Hinsberg, Ann., 1887, 2 37, p. 340); by the oxidation of an ortho-diamine in the presence of a-naphthol (0.
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.
Thus ortho-phenylene diamine yields the following products: N H N ./`N; Xn NZ In some cases oxidation of condensed benzenoid-heterocyclic nuclei results in the rupture of the heterocyclic ring with the formation of a benzene dicarboxylic acid; but if the aromatic nucleus be weakened by the introduction of an amino group, then it is the benzenoid nucleus which is destroyed and a dicarboxylic acid of the heterocyclic ring system obtained.
Tetramethylene diamine (putrescine), NH 2 ï¿½ (CH2)4.
Pentamethylene diamine (cadaverine), NH 2.
Orthophenylene diamine, C 6 H 4 (NH2)2, crystallizes from water in plates, which melt at 102 -103° C. and boil at 256-258° C. When heated with io% hydrochloric acid to 180° C. it yields pyrocatechin (Jacob Meyer, Ber., 1897, 30, p. 2569).
Metaphenylene diamine crystallizes in rhombic plates which melt at 63° C. and boil at 287° C. It is easily soluble in water and alcohol.
Paraphenylene diamine may be prepared as above, and also by the reduction of amidoazobenzene.
Above), also known as diethylene diamine, may be prepared by reducing pyrazine, or, better, by combining aniline and ethylene bromide to form diphenyl diethylene diamine, the dinitroso compound of which hydrolyses to para-dinitrosophenol and pipera zine.
The para or true quinones are obtained by the oxidation of hydrocarbons with chromic acid or of various para di-derivatives of benzene with chromic acid mixture, such, for example, as para-aminophenol, para-phenylene diamine, paraa.minoazobenzene, &c. H.
Triamino-azo-benzene: (meta-aminobenzene-azo-meta-phenylene diamine or Bismarck brown, phenylene brown, vesuvine, Manchester brown), NH 2.
PIPERAZIN, a substance formed by the action of sodium glycol on ethylene-diamine hydrochloride, consisting of small alkaline deliquescent crystals with a saline taste and soluble in water.
It is an amorphous solid which melts at 54-55° C. On reduction with sodium in alcoholic solution it yields tetraethylene diamine (putrescein) and pyrollidine.
It may be prepared synthetically by fusing meta-iodophenol, phenol meta-sulphonic acid, and benzene meta-disulphonic acid with potash; by the action of nitrous acid on meta-aminophenol; or by the action of 10% hydrochloric acid on meta-phenylene diamine (J.