2-нафтол химические свойства, назначение, производство
Химические свойства
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.
Использование
2-Naphthol is used in the manufacture of dyes, perfumes, and medicinal organics, and in the production of antioxidants for synthetic rubber.
Подготовка
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.
Определение
ChEBI: 2-naphthol is a naphthol carrying a hydroxy group at position 2. It has a role as an antinematodal drug, a genotoxin, a human xenobiotic metabolite, a mouse metabolite, a human urinary metabolite and a radical scavenger.
прикладной
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.
Реакции
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.
Общее описание
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.
Опасность
See α-naphthol
Угроза здоровью
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.
Пожароопасность
Noncombustible solid.
Профиль безопасности
Poison by ingestion,
inhalation, and subcutaneous routes.
Mutation data reported. A skin and eye
irritant. Combustible when exposed to heat
or flame. To fight fire, use CO2, dry
chemical. Incompatible with antipyrine, camphor, phenol, ferric salts, menthol,
potassium permanganate and other
oxidzing materials, urethane.
Возможный контакт
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.
Перевозки
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.
Методы очистки
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.]
Несовместимости
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.
Утилизация отходов
Mix with flammable solvent
and atomize into an incinerator.
2-нафтол препаратная продукция и сырье
сырьё
препарат