Potential Exposure
A potential danger to those involved
in rubber antioxidant production, synthesis of dyes; leather
processing; fungicides, pharmaceuticals, and perfumes.
Used as an antioxidant for fats, oils; as an antiseptic; in
insecticides.
First aid
Move victim to fresh air. Call 911 or emergency
medical service. Give artificial respiration if victim is not
breathing. Do not use mouth-to-mouth method if victim
ingested or inhaled the substance; give artificial respiration
with the aid of a pocket mask equipped with a one-way
valve or other proper respiratory medical device.
Administer oxygen if breathing is difficult. Remove and
isolate contaminated clothing and shoes. In case of contact
with substance, immediately flush skin or eyes with running
water for at least 20 minutes. For minor skin contact,
avoid spreading material on unaffected skin. Keep victim
warm and quiet. Effects of exposure (inhalation, ingestion,
or skin contact) to substance may be delayed. Ensure that
medical personnel are aware of the material(s) involved and take precautions to protect themselves. Medical observation
is recommended for 24 48 hours after breathing
overexposure, as pulmonary edema may be delayed. As
first aid for pulmonary edema, a doctor or authorized paramedic
may consider administering a drug or other inhalation
therapy.
Shipping
UN2811 Toxic solids, organic, n.o.s., Hazard
Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name
Required. UN3077 Environmentally hazardous substances,
solid, n.o.s., Hazard Class: 9; Labels: 9-Miscellaneous hazardous
material, Technical Name Required.
Incompatibilities
Dust or powder may form explosive
mixture with air. 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, iron salts; 2,3-dimethyl-1-
phenyl-3-pyrazolin-5-one (antipyrine); camphor, phenol,
menthol, urethane.
Chemical Properties
2-Naphthol is a white, crystalline solid. Slight phenolic odor. Darkens in air and on exposure to light. 2-Naphthol [135-19-3] b-naphthol, 2- naphthalenol, 2-hydroxynaphthalene, C10H8O, Mr 144.16, forms colorless plates upon sublimation, which darken on exposure to air or light. Unlike 1-naphthol it is nonvolatile in steam. 2-Naphthol is reduced with sodium or with hydrogen in the presence of a catalyst to give mainly 1,2,3,4-tetrahydro-2-naphthol (unlike 1- naphthol which gives the arylphenol under the same conditions). Oxidation with ferric chloride forms 2,20 -dihydroxy-1,10 -binaphthyl, with any blue coloration indicating the presence of 1- naphthol. Air oxidation at 300℃ with a vanadium pentoxide catalyst also yields 1,10 -bi-2-naphthol, which dehydrates at higher temperature to the oxide and finally decomposes to give benzoic acid. Treatment with sulfuryl chloride in carbon disulfide or with NaOCl – NaOH leads to 1- chloro-2-naphthol, whereas chlorine in sodium carbonate gives 8-chloro-2-naphthol ( plus 1, 10 - bi-2-naphthol). Reaction with phosphorus pentachloride at 150℃ gives 2-chloronaphthalene or at lower temperature, tri-2-naphthyl phosphate (mp 111℃), which can be isolated after treatment of the reaction mixture with alkali. Reaction with one equivalent of bromine in acetic acid gives 1-bromo-2-naphthol, whereas excess bromine yields 1,6-dibromo-2-naphthol. The latter is readily debrominated in dilute mineral acid to yield 6-bromo-2-naphthol. Excess bromine reacts with 2-naphthol at 100℃ to form 1,5,6- tribromo- and 1,3,5,6-tetrabromo-2-naphthol.
Waste Disposal
Mix with flammable solvent
and atomize into an incinerator.
Physical properties
White glossy flakes or white powder. Insoluble in water, soluble in ethanol, ether, chloroform, glycerol and alkali solution.
Uses
2-Naphthol is used in the manufacture of dyes, perfumes, and medicinal organics, and in the production of antioxidants for synthetic rubber.
Uses
anthelmintic, antiseptic
Uses
Has been used as antiseptic, anthelmintic and counter-irritant in alopecia.
Application
It is used to produce Tobias acid, J acid, 2-hydroxy-3-naphthoic acid and azo dyes, and it is the raw material for rubber antioxidants, mineral dressing agents, fungicides, antiseptics, preservatives, etc.
As feed preservative. In China, it can be used for citrus preservation, the maximum dosage amount is 0.1 g/kg and the residue amount should be no more than 70 mg/kg.
2-Naphthol, also called ?-naphthol, 2-naphthalenol, is the intermediate for plant growth regulator, 2-naphthoxyacetic acid.
As analytic agent, absorbent of ethylene and carbon monoxide, and fluorescence indicator.
Important organic raw material and dye intermediate, used to produce Tobias acid, butyric acid, β-hydroxynaphthoic acid and used to produce N-phenyl-2-naphthylamine, Diafen NN and other antioxidant, organic pigments, and fungicides.
For the detection of bromine, chlorine, chlorate, niobium, copper, nitrite, and potassium. Substrate for fluorometric assay of phenol sulfotransferase. Acid and alkali indicator, dyes, organic synthesis, qualitative determination of allyl alcohol, methanol, chloroform, etc. Absorbent of carbon monoxide, ethanol, and fluorescence indicator. Determination of carbon monoxide, copper, nitrite, and potassium. Ethylene absorbent.
Definition
ChEBI: A naphthol carrying a hydroxy group at position 2.
Preparation
2-Naphthol is produced by
caustic fusion of naphthalene-2-sulfonic acid. Typically, the sodium salt of the
sulfonic acid is added gradually to 50 % sodium
hydroxide liquor at 300℃; the melt is then
heated further at 320℃ in a gas-fired iron vessel
with vigorous agitation. After completion of the
reaction, the melt is run into excess water, possibly including filtrate from the previous batch at a
proven tolerable level, and the naphtholate solution is neutralized to pH 8 with dilute sulfuric
acid. If the temperature is maintained at >100℃ during neutralization, the crude product comes
out of solution as an oil, which is separated,
washed with hot water, and distilled under vacuum to give pure 2-naphthol. The molten material
is processed through a flaker to give the final
product for packaging. The fusion yield is about
80 % of the theoretical value, resulting in an
overall yield of 70 % based on naphthalene.
Typical specifications for 2-naphthol are clear
solution in dilute caustic soda, mp 120.5℃,
and 1-naphthol content<0.3 %.
The newer method of manufacture is economically and environmentally favored in the United States, because despite requiring three stages, it is more amenable to
continuous operation with recycle streams. The
alkylation and isomerization are carried out up to
240℃ with a phosphoric acid catalyst.
Final catalytic oxidation at 90 – 110℃ gives
the hydroperoxide, which is cleaved with dilute
sulfuric acid to give 2-naphthol in high overall
yield in spite of modest oxidation conversion.
Preparation
products were made Naphthalen-2-ol, and sodium hydroxide melting, finally using hydrochloric acid or carbon dioxide exhalation.
Reactions
2-Naphthol is naphthalene homologues of phenol, with the hydroxyl group being more reactive than in the phenols.2-Naphthol converts to 2-naphthalenethiol by reaction with dimethylthiocarbamoyl chloride via the Newman–Kwart rearrangement.
General Description
2-Naphthol (2OH) is a hydroxyarene molecule, which when electronically excited forms strong acid. Excited 2OH dissociates only in water. It has a slight phenolic odor. It is incompatible with strong oxidizing agents, strong bases, acid chlorides and acid anhydrides. It is one of the most commonly used fluorescence dye.
Health Hazard
Although the toxicity of 2-naphthol is of low order in test animals, ingestion of large amounts may result in nausea, vomiting, diarrhea, abdominal pain, convulsions, and hemolytic anemia. Death may result from respiratory failure. The oral LD50 value in rats is in the range 2000 mg/kg. 2-Naphthol is slightly more toxic than 1-naphthol [9015-3], the oral LD50 value of which is in the range 2500 mg/kg.
Skin contact can produce peeling of the skin and pigmentation.
Fire Hazard
Noncombustible solid.
Flammability and Explosibility
Notclassified
Chemical Reactivity
2-naphthol can be oxidation with ferric chloride forms 2,20 -dihydroxy-1,10 -binaphthyl, with any blue coloration indicating the presence of 1- naphthol.
Air oxidation at 300℃ with a vanadium pentoxide catalyst also yields 1,10 -bi-2-naphthol, which dehydrates at higher temperature to the oxide and finally decomposes to give benzoic acid.
2-naphthol can reacte with phosphorus pentachloride at 150℃ gives 2-chloronaphthalene or at lower temperature, tri-2-naphthyl phosphate (mp 111℃), which can be isolated after treatment of the reaction mixture with alkali.
Reaction with one equivalent of bromine in acetic acid gives 1-bromo-2-naphthol, whereas excess bromine yields 1,6-dibromo-2-naphthol. The latter is readily debrominated in dilute mineral acid to yield 6-bromo-2-naphthol.
Properties and Applications
white crystalline, with phenol smell. Industrial goods for hoar chip or powder. Melting point 121 ~ 123 ℃, 285 ℃ ~ 286 boiling point, flash point 161 ℃. This product soluble in water, ethanol, ethyl ether, chloroform, glycerin and alkali solution, can the sublimation, with steam evaporate out; Long storage or light color in turn dark, can happen oxidation, reduction, nitrification and nitrosation reaction, and products, light and heat, halogenating role, etc.
Purification Methods
Crystallise 2-naphthol from aqueous 25% EtOH (charcoal), H2O, *benzene, toluene or CCl4. Alternatively, extract it repeatedly with small amounts of EtOH, followed by dissolution in a minimum volume of EtOH and precipitation with distilled water, then drying over P2O5 under vacuum. It has also been dissolved in aqueous NaOH and precipitated by adding acid (repeat several times), then precipitated from *benzene by addition of heptane. Final purification can be by zone melting or sublimation in vacuo. The 4-nitrobenzoate has m 104o (from EtOH). [Bardez et al. J Phys Chem 89 5031 1985, Kikuchi et al. J Phys Chem 91 574 1987, Beilstein 6 IV 4253.]