Reactivity Profile
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].
Air & Water Reactions
Highly flammable. Insoluble in water.
Hazard
Toxic by inhalation. Upper respiratory tract
irritant, cataracts and hemolytic anemia. Possible
carcinogen.
Health Hazard
Fire may produce irritating and/or toxic gases. Contact may cause burns to skin and eyes. Contact with molten substance may cause severe burns to skin and eyes. Runoff from fire control may cause pollution.
Potential Exposure
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.
Fire Hazard
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.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including
resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical
attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Shipping
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.
Incompatibilities
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.
Waste Disposal
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.
History
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.
Definition
ChEBI: An aromatic hydrocarbon comprising two fused benzene rings. It occurs in the essential oils of numerous plant species e.g. magnolia.
Definition
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.
Production Methods
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.
General Description
Heterogeneous ozonolysis of naphthalene adsorbed on XAD-4 resin has been studied using annular denuder technique.
Flammability and Explosibility
Flammable
Mechanism of action
Repellent action caused by strong odour, DNA damage response
Carcinogenicity
Naphthalene is reasonably anticipated to be a human carcinogenbased on sufficient evidence from studies in experimental animals.
Source
Schauer et al. (1999) reported naphthalene in diesel fuel at a concentration of 600 μg/g
and in a diesel-powered medium-duty truck exhaust at an emission rate of 617 μg/km. Detected in
distilled water-soluble fractions of 87 octane gasoline (0.24 mg/L), 94 octane gasoline (0.21
mg/L), Gasohol (0.29 mg/L), No. 2 fuel oil (0.60 mg/L), jet fuel A (0.34 mg/L), diesel fuel (0.25
mg/L), military jet fuel JP-4 (0.18 mg/L) (Potter, 1996), and used motor oil (116 to 117 μg/L)
(Chen et al., 1994). Lee et al. (1992) investigated the partitioning of aromatic hydrocarbons into
water. They reported concentration ranges from 350 to 1,500 mg/L and 80 to 300 μg/L in diesel
fuel and the corresponding aqueous phase (distilled water), respectively. Diesel fuel obtained from
a service station in Schlieren, Switzerland contained 708 mg/L naphthalene (Schluep et al., 2001).
California Phase II reformulated gasoline contained naphthalene at a concentration of 1.04 g/kg.
Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic
converters were approximately 1.00 and 50.0 mg/km, respectively (Schauer et al., 2002).
Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from
Gainesville, FL with individual fractions of three individual petroleum products at 24–25 °C for
24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method
625. Average naphthalene concentrations reported in water-soluble fractions unleaded gasoline,
kerosene, and diesel fuel were 989, 644, and 167 ug/L.
Based on laboratory analysis of 7 coal tar samples, naphthalene concentrations ranged from 940
to 71,000 ppm (EPRI, 1990). Detected in 1-yr aged coal tar film and bulk coal tar at concentraions
of 26,000 and 29,000 mg/kg, respectively (Nelson et al., 1996). A high-temperature coal tar
contained naphthalene at an average concentration of 8.80 wt % (McNeil, 1983). Nine
commercially available creosote samples contained naphhalene at concentrations ranging from
3,800 to 52,000 mg/kg (Kohler et al., 2000). Lee et al. (1992a) equilibrated eight coal tars with
distilled water at 25 °C. The maximum concentration of naphthalene observed in the aqueous
phase was 14 mg/L.
Naphthalene was detected in soot generated from underventilated combustion of natural gas
doped with toluene (3 mole %) (Tolocka and Miller, 1995).
Typical concentration in a heavy pyrolysis oil is 17.8 wt % (Chevron Phillips, May 2003).
Detected in asphalt fumes at an average concentration of 1.15 ng/m3 (Wang et al., 2001).
An impurity identified in commercially available acenaphthene (Marciniak, 2002).
Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds,
gas-phase semi-volatile organic compounds, and particle-phase organic compounds from
the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of
naphthalene was 227 mg/kg of pine burned. Emission rates of naphthalene were not measured
during the combustion of oak and eucalyptus.
Environmental Fate
Biological. In activated sludge, 9.0% of the applied amount mineralized to carbon dioxide after 5 d (Freitag et al., 1985). Under certain conditions, Pseudomonas sp. oxidized naphthalene to cis- 1,2-dihydro-1,2-dihydroxynaphthalene (Dagley, 1972). This metabolite may be oxidized by Pseudomonas putida to carbon dioxide and water (Jerina et al., 1971). Under aerobic conditions, Cunninghamella elegans degraded naphthalene to 1-naphthol, 2-naphthol, trans-1,2-dihydroxy 1,2-dihydronaphthalene, 4-hydroxy-1-tetralone, and 1,4-naphthoquinone. Under aerobic conditions, Agnenellum, Oscillatoria, and Anabaena degraded naphthalene to 1-naphthol, cis-1,2- dihydroxy-1,2-dihydronaphthalene, and 4-hydroxy-1-tetralone (Kobayashi and Rittman, 1982; Riser-Roberts, 1992). Candida lipolytica, Candida elegans, and species of Cunninghamella, Syncephalastrum and Mucor oxidized naphthalene to 1-naphthol, 2-naphthol, trans-1,2- dihydroxy-1,2-dihydronaphthalene, 4-hydroxy-1-tetralone, 1,2-naphthoquinone, and 1,4-naphthouinone (Cerniglia et al., 1978, 1980; Dodge and Gibson, 1980).
Soil. The half-lives of naphthalene in pristine and oil-contaminated sediments are >88 d and 4.9 h, respectively (Herbes and Schwall, 1978). Reported half-lives for naphthalene in a Kidman sandy loam and McLaurin sandy loam are 2.1 and 2.2 d, respectively (Park et al., 1990).
Surface Water. The volatilization half-life of naphthalene from surface water (1 m deep, water velocity 0.5 m/sec, wind velocity 22.5 m/sec) using experimentally determined Henry’s law constants is estimated to be 16 h (Southworth, 1979). The reported half-lives of naphthalene in an oil-contaminated estuarine stream, clean estuarine stream, coastal waters, and in the Gulf stream are 7, 24, 63, and 1,700 d, respectively (Lee, 1977). Mackay and Wolkoff (1973) estimated an evaporation half-life of 2.9 h from a surface water body that is 25 °C and 1 m deep. In a laboratory experiment, the average volatilization half-life of naphthalene in a stirred water vessel (outer dimensions 22 x 10 x 21 cm) at 23 °C and an air flow rate of 0.20 m/sec is 380 min. The half-life was independent of wind velocity or humidity but very dependent upon temperature (Kl?pffer et al., 1982).
Groundwater. The estimated half-life of naphthalene in groundwater in the Netherlands was 6 months (Zoeteman et al., 1981). Nielsen et al. (1996) studied the degradation of naphthalene in a shallow, glaciofluvial, unconfined sandy aquifer in Jutland, Denmark. As part of the in situ microcosm study, a cylinder that was open at the bottom and screened at the top was installed through a cased borehole approximately 5 m below grade. Five liters of water was aerated with atmospheric air to ensure aerobic conditions were maintained. Groundwater was analyzed weekly for approximately 3 months to determine naphthalene concentrations with time. The experimentally determined first-order biodegradation rate constant and corresponding half-life following a 6-d lag phase were 0.8/d and 20.8 h, respectively.
Photolytic. Irradiation of naphthalene and nitrogen dioxide using a high pressure mercury lamp (λ >290 nm) yielded the following principal products: 1- and 2-hydroxynaphthalene, 1-hydroxy-2- nitronaphthalene, 1-nitronaphthalene, 2,3-dinitronaphthalene, phthalic anhydride, 1,3-, 1,5- and 1,8-dinitronaphthalene (Barlas and Parlar, 1987). In a similar experiment, naphthalene crystals was heated to 50 °C and exposed to pure air containing NO and OH radicals. Photodecomposition followed first-order kinetics indicating the concentration of OH radicals remained constant throughout the reaction. Degradation products identified by GC/MS were 1-naphthol, 2-naphthol, 1-nitronaphthalene, 2-nitronaphthalene, 1,4-naphthoquinone, 1,4-naphthoquinone-2,3-epoxide, 3- nitrophthalic anhydride, phthalic anhydride, 4-methyl-2H-1-benzopyran-2-one, 1(3H)-isobenzofuranone, 1,2-benzenecarboxaldehyde, cis-2-formyl-cinnamaldehyde, trans-2-formylcinnamaldehyde, and phthalide. The following compounds were tentatively identified: 2,7-naphthalenediol, 2-nitro-1-naphthol, 4-nitro-1-naphthol, and 2,4-dinitro-1-naphthol. Photoproducts identified by HPLC included: benzoic acid, cinnamic acid, 2,4-dinitro-1-naphthol, 2-formylcinnamic acid, cis-2-formylcinnamaldehyde, trans-2-formylcinnamaldehyde, 1-nitronaphthalene, 2-nitronaphthalene, 1-naphthol, 2-naphthol, 1,4-naphthoquinone, 1,4-naphthoquinone-2,3-epoxide, 3-nitrophthalic anhydride, oxalic acid, phthalic acid, phthalaldehyde, and phthalide (Lane et al., 1997).
Purification Methods
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.]
Toxicity evaluation
Systemic absorption of naphthalene vapor may result in
cataracts. The biochemical basis for naphthalene cataract has
been investigated. Naphthalene is metabolized in the liver to
1,2-dihydro-1,2-dihydroxynaphthalene. Lenticular catechol
reductase biotransforms 1,2-dihydro-1,2-dihydroxynaphthalene
to 1,2-dihydroxynaphthalene, which, in turn, is
auto-oxidized in air at neutral pH to 1,2-naphthoquinone
and hydrogen peroxide. Ascorbic acid reverses the latter
reaction and forms dehydroascorbic acid, which diffuses out
of the lens very slowly. Dehydroascorbic acid has been
shown to accumulate in the lens of rabbits that were fed
naphthalene and lens incubated in vitro with 1,2-dihydro-
1,2-dihydroxynaphthalene. The sequence of reactions
involves the reduction of ascorbic acid by 1,2-naphthoquinone
in the aqueous humor to dehydroascorbic acid,
which rapidly penetrates the lens and is reduced by glutathione.
Oxidized glutathione and 1,2-naphthoquinone may
compete for enzyme glutathione reductase, which normally
maintains high reticular levels of reduced glutathione. A
reduction in the concentration of these coupled with the
removal of oxygen from the aqueous humor due to the autooxidation
of 1,2-dihydroxynaphthalene may make the lens
sensitive to naphthalene toxicity.
Toxics Screening Level
The Initial Threshold Screening Level (ITSL) is 520 μg/m3 annual average.
