COLOURED DERIVATIVES OF PHENOL.

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Aurine Orange.

—of Turkey red. It retains, however, its importance as the raw material forthe preparation of peonine, or coralline.

This colouring matter was discovered by the younger Persoz, in 1859. Toprepare it we introduce into a strong iron vessel, capable of being closed bymeans of screws, 1 part of rosolic acid and about 3 of commercial ammonia.The vessel is heated in an oil-bath for three hours to a temperature notexceeding 150°. When cool, the contents of the vessel appear as a thickliquid with a golden crimson refledtion. The colouring matter is precipitatedfrom this liquid by the addition of hydrochloric acid. If well prepared, peonineis almost insoluble in water, but very soluble in alcohol, to which it com-municates a red colour. Its alkaline solutions gradually take a brown colouron exposure to the air.

Coralline Yellow.