Azobenzene

(az-o-ben’ ’-zen) [azote, nitrogen; benzoin], C12H10N2. A compound formed by the action of sodium-amalgam upon the alcoholic solution of nitro-benzene. It forms orange-red, rhombic crystals, readily soluble in alcohol and ether, but sparingly soluble in water. It melts at 68°, and distils at 2930. Azo-compounds. In chemistry, compounds intermediate between the nitro compounds and the amido-compounds, and made from the former by partial reduction, or from the latter by partial oxidation. Azo-dyes. A well defined group of the coaltar colors, all containing the diatomic group — N=N —, bound on either side to a benzene radical. They may be prepared by reduction of the nitro compounds in alkaline solutions, or by acting on diazo-compounds with phenols or amins of the aromatic series. The azo-dyes are the amido-derivatives of simple azo-compounds, and are to be distinguished as amidoazo-dyes and oxyazo-dyes. 104