Нафталин

Описание

Naphthalene occurs as transparent prismatic plates also available as white scales, powder balls, or cakes with a characteristic mothball or strong coal tar and aromatic odour. It is sparingly soluble in water but soluble in methanol/ethanol and very soluble in ether. Naphthalene is a commercially important aromatic hydrocarbon. Naphthalene occurs as a white solid or powder. Naphthalene occurs in coal tar in large quantities and is easily isolated from this source in pure condition. It volatilises and sublimes at room temperature above the melting point. The primary use for naphthalene is in the production of phthalic anhydride, also of carbamate insecticides, surface active agents and resins, as a dye intermediate, as a synthetic tanning agent, as a moth repellent, and in miscellaneous organic chemicals. Naphthalene is used in the production of phthalic anhydride; it is also used in mothballs. Naphthalene is also used in the manufacture of phthalic and anthranilic acids to make indigo, indanthrene, and triphenyl methane dyes, for synthetic resins, lubricant, celluloid, lampblack, smokeless powder, and hydronaphthalenes. Naphthalene is also used in dusting powders, lavatory deodorant discs, wood preservatives, fungicide, and as an insecticide. It has been used as an intestinal antiseptic and vermicide and in the treatment of pediculosis and scabies.

Химические свойства

Naphthalene is a colorless to brown crystalline solid with a characteristic “moth ball” odor. It evaporates easily and has a strong odor of tar or mothballs. Solubility in water is low (31.7 mg/l at 25 °C), and it is soluble in benzene, alcohol, ether, and acetone (ATSDR, 2005). Shipped as a molten solid.

История

In 1819, naphthalene was obtained as white crystals during the pyrolysis of coal tar by John Kidd (1775–1851), a British physician and chemist, and Alexander Garden (1757–1829), an American living in Britain. Kidd described the properties of the white crystals he obtained from coal tar and proposed the named naphthaline for the substance; naphthaline was derived from naphtha, a general term for a volatile, fl ammable, hydrocarbon liquid. Michael Faraday (1791–1867) determined the correct empirical formula for naphthalene in 1825, and Richard August Carl Emil Erlenmeyer (1825–1909) proposed the fused benzene ring structure in 1866.

Методы производства

Naphthalene is produced from coal tar or petroleum. It is made from petroleum by dealkylationof methylnaphthalenes in the presence of hydrogen at high temperature and pressure.Petroleum was a major source of naphthalene until the 1980s, but now most naphthaleneis produced from coal tar. The pyrolysis of bituminous coal produces coke and coke ovengases. Naphthalene is condensed by cooling the coke gas and then separated from the gas.

Определение

naphthalene: A white volatilesolid, C₁₀H₈; r.d. 1.025;m.p. 80.55°C; b.p. 218°C. Naphthaleneis an aromatic hydrocarbon withan odour of mothballs and is obtainedfrom crude oil. It is a raw materialfor making certain syntheticresins.

Общее описание

Heterogeneous ozonolysis of naphthalene adsorbed on XAD-4 resin has been studied using annular denuder technique.

Реакции воздуха и воды

Highly flammable. Insoluble in water.

Профиль реактивности

Vigorous reactions, sometimes amounting to explosions, can result from the contact between aromatic hydrocarbons, such as Naphthalene, and strong oxidizing agents. They can react exothermically with bases and with diazo compounds. Substitution at the benzene nucleus occurs by halogenation (acid catalyst), nitration, sulfonation, and the Friedel-Crafts reaction. Naphthalene, camphor, glycerol, or turpentine will react violently with chromic anhydride [Haz. Chem. Data 1967. p 68]. Friedel-Crafts acylation of Naphthalene using benzoyl chloride, catalyzed by AlCl3, must be conducted above the melting point of the mixture, or the reaction may be violent [Clar, E. et al., Tetrahedron, 1974, 30, 3296].

Опасность

Toxic by inhalation. Upper respiratory tract irritant, cataracts and hemolytic anemia. Possible carcinogen.

Пожароопасность

Flammable/combustible material. May be ignited by friction, heat, sparks or flames. Some may burn rapidly with flare burning effect. Powders, dusts, shavings, borings, turnings or cuttings may explode or burn with explosive violence. Substance may be transported in a molten form at a temperature that may be above its flash point. May re-ignite after fire is extinguished.

Профиль безопасности

Human poison by ingestion. Experimental poison by ingestion, intravenous, and intraperitoneal routes. Moderately toxic by subcutaneous route. An experimental teratogen. Experimental reproductive effects. An eye and skin irritant. Can cause nausea, headache, daphoresis, hematuria, fever, anemia, liver damage, vomiting, convulsions, and coma. Poisoning may occur by ingestion of large doses, inhalation, or skin absorption. Questionable carcinogen with experimental tumorigenic data. Flammable when exposed to heat or flame; reacts with oxidizing materials. Explosive reaction with dinitrogen pentaoxide. Reacts violently with CrOs, aluminum chloride + benzoyl chloride. Fires in the benzene scrubbers of coke oven gas plants have been attributed to oxidation of naphthalene. Explosive in the form of vapor or dust when exposed to heat or flame. To fight fire, use water, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes.

Возможный контакт

Naphthalene is used as a chemical intermediate or feedstock for synthesis of phthalic, anthranilic, hydroxyl (naphthols), amino (naphthylamines), and sulfonic compounds; which are used in the manufacture of various dyes and in the preparation of phthalic anhydride, 1-naphthyl-N-methyl carbonate; and β-naphthol. Naphthalene is also used in the manufacture of hydronaphthalenes, synthetic resins; lampblack, smokeless powder; and celluloid. Naphthalene has been used as a moth repellent.
Approximately 100 million people worldwide have G6PD deficiency which would make them more susceptible to hemolytic anemia on exposure to naphthalene. At present, more than 80 variants of this enzyme deficiency have been identified. The incidence of this deficiency is 0.1% in American and European Caucasians, but can range as high as 20% in American blacks and greater than 50% in certain Jewish groups. Newborn infants have a similar sensitivity to the hemolytic effects of naphthalene, even without G6PD deficiency.

Канцерогенность

Naphthalene is reasonably anticipated to be a human carcinogenbased on sufficient evidence from studies in experimental animals.

Перевозки

UN1334 Naphthalene, crude or Naphthalene, refined, Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN2304 (molten) Hazard Class: 4.1; Labels: 4.1-Flammable solid.

Методы очистки

Crystallise naphthalene once or more times from the following solvents: EtOH, MeOH, CCl4, *C6H6, glacial acetic acid, acetone or diethyl ether, followed by drying at 60o in an Abderhalden drying apparatus. It has also been purified by vacuum sublimation and by fractional crystallisation from its melt. Other purification procedures include refluxing in EtOH over Raney Ni and chromatography of a CCl4 solution on alumina with *benzene as eluting solvent. Baly and Tuck [J Chem Soc 1902 1908] purified naphthalene for spectroscopy by heating with conc H2SO4 and MnO2, followed by steam distillation (repeating the process), and formation of the picrate which, after recrystallisation (m 150o) is decomposed with base and the naphthalene is steam distilled. It is then crystallised from dilute EtOH. It can be dried over P2O5 under vacuum (take care not to make it sublime). Also purify it by sublimation and subsequent crystallisation from cyclohexane. Alternatively, it has been washed at 85o with 10% NaOH to remove phenols, with 50% NaOH to remove nitriles, with 10% H2SO4 to remove organic bases, and with 0.8g AlCl3 to remove thianaphthalenes and various alkyl derivatives. Then it is treated with 20% H2SO4, 15% Na2CO3 and finally distilled. [Gorman et al. J Am Chem Soc 107 4404 1985.] Zone refining purified naphthalene from anthracene, 2,4-dinitrophenylhydrazine, methyl violet, benzoic acid, methyl red, chrysene, pentacene and indoline. [Beilstein 5 IV 1640.]

Несовместимости

Dust 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. Violent reactions with chromium(III) oxide, dinitrogen pentoxide; chromic anhydride.

Утилизация отходов

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. 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.

использованная литература

Formation Mechanisms of Naphthalene and Indene: From the Interstellar Medium to Combustion Flames. DOI:10.1021/acs.jpca.6b09735
Functional Naphthalene Diimides: Synthesis, Properties, and Applications. DOI:10.1021/ACS.CHEMREV.6B00160
The 100 Most Important Chemical Compounds: A Reference Guide DOI:10.5860/choice.45-3798
A comprehensive guide to the hazardous properties of chemical substances DOI:10.1002/9780470134955
A Dictionary of Chemistry (6th edition) DOI:10.1108/09504120910935291
TOXICOLOGICAL REVIEW of NAPHTHALENE
Naphthalene - Environmental Protection Agency