1-naphthylamine

1-Naphthylamine

1-Naphthylamine

Chemical compound


1-Naphthylamine is an aromatic amine derived from naphthalene. It can cause bladder cancer (transitional cell carcinoma). It crystallizes in colorless needles which melt at 50 °C. It possesses a disagreeable odor, sublimes readily, and turns brown on exposure to air. It is the precursor to a variety of dyes.[2]

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Preparation and reactions

It can be prepared by reducing 1-nitronaphthalene with iron and hydrochloric acid followed by steam distillation.[2]

Oxidizing agents, such as ferric chloride, give a blue precipitate with solutions of its salts. Chromic acid converts it into 1-naphthoquinone. Sodium in boiling amyl alcohol reduces the unsubstituted ring, giving tetrahydro-1-naphthylamine. This tetrahydro compound yields adipic acid when oxidized by potassium permanganate.

At 200 °C in sulfuric acid, it converts to 1-naphthol.

Use in dyes

The sulfonic acid derivatives of 1-naphthylamine are used for the preparation of azo dye. These compounds possess the important property of dyeing unmordanted cotton.

An important derivative is naphthionic acid (1-aminonaphthalene-4-sulfonic acid), which is produced by heating 1-naphthylamine and sulfuric acid to 170–180 °C in the presence of crystallized oxalic acid. It forms small needles, very sparingly soluble in water. Upon treatment with the bis(diazonium) derivative of benzidine, 1-aminonaphthalene-4-sulfonic acid gives Congo red.

Safety

It is listed as one of the 13 carcinogens covered by the OSHA General Industry Standards.[3]

See also


References

  1. NIOSH Pocket Guide to Chemical Hazards. "#0441". National Institute for Occupational Safety and Health (NIOSH).
  2. Gerald Booth (2005). "Naphthalene Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_009. ISBN 9783527303854..

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