Aniline brown

Aniline Brown dye on wool after exposure to 85 Mlx-h
Credit: E. Hagan et al.

Description

A synthetic brown dye prepared by heating rosaniline with an oxidizing agent such as ammonium chromate. Aniline brown was first made by Jacobson using this method. Many other aniline brown colorants, such as Bismarck brown, are chemically similar (triamido-azobenzene hydrochloride) but are derived from aromatic diamines via diazotization. Aniline Brown directly forms a reddish brown color with silk and a rich brown color with wool. The brown dyes deeply penetrate the fibers of materials rather than just sitting on the surface. This provides a transparent, vibrant coloration that beautifully preserves the visibility of underlying textures, such as wood grain or the natural hide of leather.

Synonyms and Related Terms

Basic Brown 1; Bismarck brown, Manchester Brown

Risks

• Early aniline dyes can be toxic and cause skin irritation

Physical and Chemical Properties

• Insoluble in water
• Soluble in alcohol and other organic solvents

Resources and Citations

• F. Crace-Calvert, Dyeing and Calico Printing, Palmer & Howe, London, 1876
• E. Hagan, I. Castro-Soto, M. Breault, et al. The lightfastness of early synthetic organic dyes. Herit Sci 10, 50 (2022).