2-Naphthylamine

• 2- Aminonaphthalene
• β -naphthylamine

White, on the air discoloring reddish crystals with an unpleasant odor

Fixed

1.220 g · cm -3

110.2 ° C

306.1 ° C

Sparingly soluble in water

Risk

727 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

2-naphthylamine is a derivative of naphthalene. It belongs to the group of aromatic amino compounds. In addition to the 2-naphthylamine, there are the isomers of 1-naphthylamine.

History

In 1895 it was reported " in fuchsin workers Blasengeschwülsten " by the surgeon Ludwig Rehn an increased incidence of. Rhen suspected that the cancers were caused by aniline. It is, however, now accepted that aniline only has a very low potential for the formation of bladder cancer. From 1925, " Diseases caused by nitro and amino compounds of the aromatic series " have been recognized as an occupational disease in the first occupational disease regulation in Germany. 1936, the title of the occupational disease regulation has been changed " Diseases caused by cancer or other neoplasms as well as changes in the mucosa of the urinary bladder by aromatic amines ", which still to this day has in this form inventory.

Interestingly, could be triggered by aromatic amines up to today in the usual experimental animals mouse and rat urinary bladder tumors no. WC 1938 could Hueper and colleagues in experiments with dogs first trigger in an animal model with 2- naphthylamine bladder cancer. To date, dogs and humans are the only known species that can form an induced by aromatic amines bladder cancer. The reason is that dogs have no activity of the enzyme N-acetyltransferase, which secure detoxification of the aromatic amines of the N-acetylation would be possible. 1943, the production of 2 -naphthylamine was set in Germany. In 1972 Japan as the last industrialized nation.

Production and representation

2-naphthylamine can be prepared by reaction of 2 - naphthol with ammonium zinc chloride at 200 to 210 ° C. If 2-naphthol is heated with ammonium acetate at 270 to 280 ° C, the acetyl derivative of 2- naphthylamine forms.

Toxicity

The 2- naphthylamine -induced tumors are formed mainly on the urinary tract and there especially on the urinary bladder. The malignant neoplasms develop partially until decades after exposure to 2-naphthylamine. Typical are sessile sessile or pedunculated papillomas. In addition, there is evidence that other tumors can be generated by 2-naphthylamine. According to some studies, the individual metabolism (metabolism ) plays a crucial role in disease risk.

2-naphthylamine may be apparent from the de phenylation in the metabolism of N-phenyl -2-naphthylamine ( PBNA ), a rubber additive arise.

Metabolism

2-naphthylamine renally excreted with a half -life of about seven hours. Two different Metabolisierungsschritte are possible: A N-acetylation or N- hydroxylation. N-acetylation leads to a substantial detoxification of the substance, while the N- hydroxylation into the erythrocyte to the N- nitroso-2 -naphthylamine. The nitroso compound can bind to the thiol groups of glutathione or the hemoglobin. Part of it is, however, derived as a conjugate with glucuronic acid to the kidney and released there in the urine again. This produces Arylnitrenium ions, which can react for example with the mucous membranes of the urinary bladder and there can bind to proteins, but also DNA and RNA, which ultimately means a carcinogenic effect.

People, in which the metabolism of 2- naphthylamine is preferably carried by the N- acetylation in the sequence have a lower risk of an induced by 2-naphthylamine cancer.

Use

2-naphthylamine was formerly used for the preparation of azo dyes and as anti-aging agent ( antioxidant) of rubber. The substance is not released from textiles or leather articles which may come a long time with the human skin directly in contact are (Appendix 1 of the Consumer Goods Ordinance ) after reductive cleavage of azo groups. Due to its proven human carcinogen, it is rarely used industrially. It has been largely replaced by safer materials.