Aurin

• C. I. 43800
• 4 - [ bis (4 -hydroxyphenyl) methylene] - 2,5 -cyclohexadienone
• P- rosolic
• Corallin

Red-brown solid

Fixed

Insoluble in water, soluble in alkali solutions and acids

Attention

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Preparation and Properties

Aurin forms during heating phenol with oxalic acid in concentrated sulfuric acid, the latter acting as condensation and oxidation agents:

The yellow-brown or red substance dissolves in alkalies Fuchsia and serves as a pH indicator. The sodium salt is used for coloring wallpaper and paper. The absorption maximum at λ = 482 nm