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naphthalene

Product name naphthalene
Synonyms naphthalin
naphthaline
tar camphor
white tar
albocarbon
naphthene
GOST 16106-82
CAS 91-20-3

Naphthalene is a colorless crystalline compound with a characteristic odor. It can be easily sublimed forming a flammable vapor. Naphthalene is soluble in most organic solvents; has a low solubility in water (0.0344 g/L at 25°C). Its molecules are plain and consist of two fused benzene rings. Naphthalene has two sets of equivalent hydrogens. The alpha positions are positions 1, 4, 5, and 8, the beta positions are positions 2, 3, 6, and 7. Like benzene, naphthalene can undergo electrophilic aromatic substitution. Usually, the major product has the electrophile in the alpha position. The process occurs at more soft conditions than in benzene. Also, naphthalene can be oxidized with Cr2O3 to form 1,4-naphthoquinone; oxidation with air at 350-500°C in the presence of Mo2O3 or V2O5 results in phthalic anhydride. Naphthalene can be hydrogenated under high pressure or with a suitable catalyst to give depending on conditions 1,2-dihydronaphthalene, 1,4-dihydronaphthalene, 1,2,3,4-tetrahydronaphthalene (tetralin) or decahydronaphthalene (decalin).

Production.

Most naphthalene is derived from coal tar. Typical coal tar is about 10% naphthalene by weight. Naphthalene in crystallized from coal tar fraction with boiling point 210-220°C than it is washed with sulfuric acid solution to remove thiophene, with diluted alkali to remove phenol and, finally, is distilled. Also naphthalene is produced from heavy petroleum fractions during petroleum refining, but today petroleum-derived napthalene represents only a minor component of production.

Uses.

  • as a feedstock in making phthalic anhydride, decalin, tetralin, naphthols, naphthyl amines and other chemicals;
  • as an intermediate in preparation of azo dyes, surfactants, pharmaceuticals, insecticides;
  • as insecticide (the primary ingredient of mothballs);

  • Manufacturer(s) Dzerzhinsk phenol plant
    OJSC Nizhniy Tagil Iron and Steel Works, COKE OVEN AND BY-PRODUCT PLANT
    JSC SEVERSTAL, COKE OVEN AND BY-PRODUCT PLANT
    JSC West-Siberian Metallurgical Plant, COKE OVEN AND BY-PRODUCT PLANT
    Chemical structure of naphthalene

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