2-Naphthylamine or 2-aminonaphthalene is one of two

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ...

ic aminonaphthalenes, compounds with the formula C₁₀H₇NH₂. It is a colorless solid, but samples take on a reddish color in air because of oxidation. It was formerly used to make

azo dye Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl and substituted aryl groups. They are a commercially important family of azo compounds, i.e. compounds containing the C−N=N−C l ...

s, but it is a known

carcinogen A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruse ...

and has largely been replaced by less toxic compounds.Gerald Booth "Naphthalene Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. .

Preparation

2-Naphthylamine is prepared by heating 2-naphthol with

ammonium Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...

zinc chloride Zinc chloride is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula ZnCl2·''n''H2O, with ''n'' ranging from 0 to 4.5, forming water of hydration, hydrates. Zinc chloride, anhydrous and its hydrates, are colo ...

to 200-210 °C, the Bucherer reaction. Its

acetyl In organic chemistry, an acetyl group is a functional group denoted by the chemical formula and the structure . It is sometimes represented by the symbol Ac (not to be confused with the element actinium). In IUPAC nomenclature, an acetyl grou ...

derivative can be obtained by heating 2-naphthol with

acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetallic, or radical base). "Acetate" also describes the conjugate base or ion (specifically, the negatively charged ion called ...

to 270-280 °C.

Reactions

It gives no color with

iron(III) chloride Iron(III) chloride describes the inorganic compounds with the formula (H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated f ...

. When reduced by

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

in boiling

amyl alcohol Amyl alcohols are alcohols with the formula C5H11OH. Eight are known. A mixture of amyl alcohols (also called amyl alcohol) can be obtained from fusel alcohol. Amyl alcohol is used as a solvent and in esterification, by which is produced amy ...

solution, it forms tetrahydro-3-naphthylamine, which exhibits the properties of the

aliphatic In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated (in which all ...

amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

s in that it is strongly

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

in reaction, has an

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

cal odor and cannot be

diazo In organic chemistry, the diazo group is an organic moiety consisting of two linked nitrogen atoms at the terminal position. Overall charge-neutral organic compounds containing the diazo group bound to a carbon atom are called diazo compounds ...

tized. On

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

, it yields ''ortho''-carboxy-hydrocinnamic acid, HO₂CC₆H₄CH₂CH₂CO₂H. Numerous

sulfonic acid In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is kn ...

derivatives of 2-naphthylamine are used in commerce, such as precursors to

dye Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...

s. Owing to the carcinogenicity of the amine, these derivatives are mainly prepared by amination of the corresponding naphthols. Of them, the δ-acid and Bronner's acid are of more value technically, since they combine with ''ortho''-tetrazoditolyl to produce fine red dye-stuffs. 2-Naphthylamine was previously used as a dye precursor and rubber antioxidant in the 1930s, 40s and 50s. Dupont stopped using it in the 1970s.

Role in disease

2-Naphthylamine is found in

cigarette A cigarette is a narrow cylinder containing a combustible material, typically tobacco, that is rolled into Rolling paper, thin paper for smoking. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhale ...

smoke and suspected to contribute to the development of

bladder cancer Bladder cancer is the abnormal growth of cells in the bladder. These cells can grow to form a tumor, which eventually spreads, damaging the bladder and other organs. Most people with bladder cancer are diagnosed after noticing blood in thei ...

.CDC - NIOSH Pocket Guide to Chemical Hazards
/ref> It is activated in the liver but quickly deactivated by conjugation to

glucuronic acid Glucuronic acid (GCA, from ) is a uronic acid that was first isolated from urine (hence the name "uronic acid"). It is found in many natural gum, gums such as gum arabic ( 18%), xanthan, and kombucha tea and is important for the metabolism of ...

. In the bladder, glucuronidase re-activates it by deconjugation, which leads to the development of bladder cancer.

References

{{DEFAULTSORT:Naphthylamine, 2- IARC Group 1 carcinogens Naphthylamines 2-Naphthyl compounds

Preparation

Reactions

Role in disease

See also

References