Chemical Properties
α-Naphthylamine exists as white needle-like crystals which turn red on exposure to air. Has a weak ammonia-like odor. Solubility in water is 0.16% at 20℃. It behaves as a typical primary aromatic amine in forming salts with strong acids (but not with acetic or benzoic acid) and readily forming N-acyl derivatives. 1-Naphthylamine couples with diazo compounds in the 4-position, with up to 10 % byproduct being formed by coupling in the 2-position.
Physical properties
White to yellow crystals or rhombic needles with an unpleasant odor. Becomes purplish-red on exposure to air. Odor threshold concentrations were 140–290 μg/m3 (quoted, Keith and Walters, 1992).
Uses
1-Naphthylamine is used as a chemical intermediate in the synthesis of a wide variety of chemicals, the most important of which include dyes, tonic prints, Toning prints made with cerium salts, antioxidants, and herbicides.
Application
1-Naphthylamine is mainly used for the production of 1-naphthol. Other major uses are in the production of aminonaphthalenesulfonic acid dye intermediates and as a component of azo dyes.
1-Naphthylamine can also be used as a starting material to synthesize:
[(S)-HY-Phos], a novel chiral phosphine-phosphoramidite ligand for use in rhodium-catalyzed asymmetric hydrogenation of various functionalized olefins.
N-(naphthalen-1-yl)picolinamide.
Pitnot-2, an inactive analog of clathrin inhibitor Pitstop 2.
Preparation
1-Naphthylamine is prepared by reduction of 1-nitronaphthalene: Purified 1-nitronaphthalene was traditionally reduced with iron in boiling dilute hydrochloric acid, but modern plants use hydrogenation with a nickel catalyst. The 1-naphthylamine produced is further purified by distillation under vacuum. The content of 2-naphthylamine in the commercial product is specified at <10 ppm.
Definition
ChEBI: 1-naphthylamine is a naphthylamine that is naphthalene substituted by an amino group at position 1. It has a role as a human xenobiotic metabolite.
General Description
1-naphthylamine appears as a crystalline solid or a solid dissolved in a liquid. Insoluble in water and denser than water. Contact may slightly irritate skin, eyes and mucous membranes. May be slightly toxic by ingestion. Used to make other chemicals.
Air & Water Reactions
Sensitive to exposure to air and light. Insoluble in water. Napthyl amines can be slowly hydrolyzed, releasing NH3 as a byproduct [N.L. Drake, Org. React. 1, (1942), 105].
Reactivity Profile
1-Aminonaphthalene is incompatible with oxidizing agents. 1-Aminonaphthalene is also incompatible with nitrous acid. 1-Aminonaphthalene reduces warm ammoniacal silver nitrate. .
Hazard
Toxic, especially if containing the β isomer;
a questionable carcinogen.
Health Hazard
1-Naphthylamine is a moderately toxic and cancer-causing substance. The toxic symptoms arising from oral intake or skin absorption of this compound include acute hemorrhagic cystitis, dyspnea, ataxia, dysuria, and hematuria. An intraperitoneal LD50 value in mice is 96 mg/kg. Inhalation of dusts or vapors is hazardous, showing similar symptoms. 1-Naphthylamine caused leukemia in rats. There is substantial evidence of its cancer-causing effects in animals and humans.
Fire Hazard
Special Hazards of Combustion Products: Toxic nitrogen oxides are produced in a fire.
Safety Profile
Confirmed carcinogen
with experimental tumorigenic data. Along
with p-naphthylamine and benzidine, it has
been incriminated as a cause of urinary
bladder cancer. Poison by subcutaneous and
intraperitoneal routes. Moderately toxic by
ingestion. Mutation data reported.
Combustible when exposed to heat or
flame. Incompatible with nitrous acid. To
fight fire, use dry chemical, CO2, mist, spray.
When heated to decomposition it emits
toxic fumes of NOx.
Potential Exposure
α-Naphthylamine is used as an intermediate
in dye production; for manufacturing herbicides
and antioxidants; in the manufacture of condensation
colors, rubber, and in the synthesis of many chemicals,
such as α-naphthol, sodium naphthionate; o-naphthionic
acid; Neville and Winther’s acid; sulfonated naphthylamines,
α-naphthylthiourea (a rodenticide); and N-phenyl-
α-naphthylamine.
Carcinogenicity
1-Naphthylamine has been tested for carcinogenic activity
in mice, hamsters, and dogs by oral administration, in
newborn mice by SC injection, and in mice by bladder
implantation. Most of these studies reported
negative findings, while a few found marginal or equivocal
results. In contrast, with the exception of bladder implantation
study, 2-naphthylamine gave positive results in virtually
all these studies. Mixed results were reported in various
genotoxicity tests. 1-Naphthylamine was positive in the
Ames test and in vitro chromosome aberration, negative in
micronucleus, cell transformation, and recessive lethal mutation
in Drosophila, and inconclusive in sister chromatid
exchange assays.
Environmental Fate
Biological. 1-Naphthylamine added to three different soils was incubated in the dark at 23 °C
under a carbon dioxide-free atmosphere. After 308 d, 16.6 to 30.7% of the 1-naphthylamine added
to soil biodegraded to carbon dioxide (Graveel et al., 1986). Li and Lee (1999) investigated the
reaction of 10 mL of 7 mM 1-naphthylamine with 4 g of a Chalmers soil (pH: 6.5, 11.1% sand,
72.8% silt, 16.0% clay). After 120 h, the soil was washed with acetonitrile and the extractant
analyzed using GC/MS. The primary transformation product was a dimer tentatively identified as
N-(4-aminonaphthyl)-1-naphthylamine. The investigators hypothesized that the formation of this
compound and two other unidentified dimers was catalyzed by minerals present in the soil.
Heukelekian and Rand (1955) reported a 5-d BOD value of 0.89 g/g which is 34.6% of the
ThOD value of 2.57 g/g. In activated sludge inoculum, following a 20-d adaptation period, no
degradation was observed (Pitter, 1976).
Photolytic. Low et al. (1991) reported that the photooxidation of aqueous primary amine
solutions by UV light in the presence of titanium dioxide resulted in the formation of ammonium
and nitrate ions.
Chemical/Physical. Kanno et al. (1982) studied the aqueous reaction of 1-naphthylamine and
other substituted aromatic hydrocarbons (aniline, toluidine, 2-naphthylamine, phenol, cresol,
pyrocatechol, resorcinol, hydroquinone, and 1-naphthol) with hypochlorous acid in the presence of
ammonium ion. They reported that the aromatic ring was not chlorinated as expected but was
cleaved by chloramine forming cyanogen chloride. The amount of cyanogen chloride that formed
increased as the pH was lowered (Kanno et al., 1982).
At influent concentrations (pH 3.0) of 10, 1.0, 0.1, and 0.01 mg/L, the GAC adsorption capacities
were 250, 140, 79, and 44 mg/g, respectively. At pHs 7.0 and 9.0, the GAC adsorption capacities
were 360, 160, 75, and 34 mg/g at influent concentrations of 10, 1.0, 0.1, and 0.01 mg/L,
respectively (Dobbs and Cohen, 1980).
Shipping
UN2077 alpha-Naphthylamine, Hazard Class:
6.1; Labels: 6.1-Poisonous materials. PGIII.
Purification Methods
Sublime the amine at 120o in a stream of nitrogen, then crystallise it from pet ether (b 60-80o), or absolute EtOH then diethyl ether. Dry it in vacuo in an Abderhalden pistol. It has also been purified by crystallisation of its hydrochloride (see below) from water, followed by liberation of the free base and distillation; it is finally purified by zone melting. The styphnate has m 181-182o (from EtOH). [Beilstein 12 III 2846, 12 IV 3009.] CARCINOGEN.
Incompatibilities
Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides, nitrous acid, organic
anhydrides, isocyanates, aldehydes. Oxidizes on contact
with air.
Waste Disposal
Controlled incineration
whereby oxides of nitrogen are removed from the effluent
gas by scrubber, catalyst, or thermal device. Consult with
environmental regulatory agencies for guidance on
acceptable disposal practices. Generators of waste containing
this contaminant (≥100 kg/mo) must conform with
EPA regulations governing storage, transportation, treatment,
and waste disposal.
