Chrysoidine production

The preparation of the first cationic azo dye, Vesuvin, was described by C. Martius in 1863. It is obtained by coupling diazotized m-phenylcncdiamine to an excess of the same amine. An analogous dye from toluylenediamine was reported by P. Gries in 1878. Chrysoidines, coupling products of aniline or toluidines to m-phenylenediamine or toluylenediamine, were reported by H. Caro in 1875 and O. N. Witt in 1876. 

Chrysoidine dye salts of dodecylbenzenesulfonic acid are soluble in glycols and glycol ethers and are used in the production of inks, printing inks, and varnishes [2],... 

Chrysoidine (Diaminoazobenzene or 4-Phenylazo -m-phenylene diamine Hydrochloride) [called 2,4 -Diamino-azobenzol 4-Benzolazo-phenylenediamin -(1.3) or Base des Chrysoidins in Ger], CgHg. N N.CgH3(NH2)2 mw 212.25, N 26-40% yel ndls (from hot w), mp 117.5° S°1 in ale, eth, chlf, benz or aniline si sol in hot w. It forms numerous salts which are cryst comds. The Hydrochloride (also called Chrysoidine Y or Chrysoidine Extra), C12 12V C1, red-brn powd or large, black shiny crysts having a green luster, is the commercial product. The Dihydrochloride, col crysts (from ale), dec at 222°. Other props methods of prepn are given in Ref 1... 

For ten years after this no particular progress was made in this field, and the first synthetical production of azo-compounds appears with the discovery of chrysoidine by Witt and Caro. 

Metaphenylenediamine may also be used, but the products are not so fast to light. Triamidoazobenzenes (Bismark brown) and Chrysoidine give soluble indulines on heating with paraphenylenediamine. 

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