NAPHTHALENE

CAS NO.: 91-20-3
EC/LIST.: 214-552-7

Naphthalene is an organic compound with formula C10H8. 
Naphthalene  is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass.
As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. 
Naphthalene  is best known as the main ingredient of traditional mothballs.

Naphthalene is a white, volatile, solid polycyclic hydrocarbon with a strong mothball odor. 
Naphthalene is obtained from either coal tar or petroleum distillation and is primarily used to manufacture phthalic anhydride, but is also used in moth repellents. 
Exposure to naphthalene is associated with hemolytic anemia, damage to the liver and neurological system, cataracts and retinal hemorrhage. 
Naphthalene is reasonably anticipated to be a human carcinogen and may be associated with an increased risk of developing laryngeal and colorectal cancer.

Naphthalene appears as a white crystalline volatile solid with a strong coal-tar odor. 
The solid is denser than water and insoluble in water. 
Burns, but may be difficult to ignite. . 
In the molten form it is very hot. 
Exposure to skin must be avoided. 
Also the vapors given off by the material may be toxic. 
Used as a moth repellent, fumigant, lubricants, and to make other chemicals, and for many other uses

Naphthalene is an aromatic hydrocarbon comprising two fused benzene rings. 
Naphthalene occurs in the essential oils of numerous plant species e.g. magnolia. 
Naphthalene  has a role as a volatile oil component, a plant metabolite, an environmental contaminant, a carcinogenic agent, a mouse metabolite and an apoptosis inhibitor. 
Naphthalene  is an ortho-fused bicyclic arene and a member of naphthalenes.

Naphthalene is made from crude oil or coal tar. 
Naphthalene  is also produced when things burn, so naphthalene is found in cigarette smoke, car exhaust, and smoke from forest fires. 
Naphthalene  is used as an insecticide and pest repellent. 
Naphthalene was first registered as a pesticide in the United States in 1948.

Mothballs and other products containing naphthalene are solids that turn into toxic gas. 
The toxic gas kills insects and may repel animals. 
There are over a dozen products containing naphthalene registered for use by the U.S. Environmental Protection Agency (U.S. EPA).

Always follow label instructions and take steps to avoid exposure. 
If any exposures occur, be sure to follow the First Aid instructions on the product label carefully.

naphthalene, the simplest of the fused or condensed ring hydrocarbon compounds composed of two benzene rings sharing two adjacent carbon atoms; chemical formula, C10H8. 
Naphthalene  is an important hydrocarbon raw material that gives rise to a host of substitution products used in the manufacture of dyestuffs and synthetic resins. 
Naphthalene is the most abundant single constituent of coal tar, a volatile product from the destructive distillation of coal, and is also formed in modern processes for the high-temperature cracking (breaking up of large molecules) of petroleum. 
Naphthalene  is commercially produced by crystallization from the intermediate fraction of condensed coal tar and from the heavier fraction of cracked petroleum. 
The substance crystallizes in lustrous white plates, melting at 80.1° C (176.2° F) and boiling at 218° C (424° F). 
Naphthalene  is almost insoluble in water. 
Naphthalene is highly volatile and has a characteristic odour; it has been used as moth repellent.

In its chemical behaviour, naphthalene shows the aromatic character associated with benzene and its simple derivatives. 
Naphthalene  reactions are mainly reactions of substitution of hydrogen atoms by halogen atoms, nitro groups, sulfonic acid groups, and alkyl groups. 
Large quantities of naphthalene are converted to naphthylamines and naphthols for use as dyestuff intermediates. 
For many years napthalene was the principal raw material for making phthalic anhydride.

Naphthalene is the most abundant component of coal tar, which is the liquid byproduct of the distillation of coal into coke for use as a smokeless fuel.

The most common current use for naphthalene is as a raw material in the production of phthalic anhydride, which is often used in the production of dyes, plasticizers, insecticides and some pharmaceutical products.

In the past, naphthalene was used as a fumigant for repelling moths, for which it is popularly known as mothballs. 
Another classical use of naphthalene was as a fumigant for soil. 
Such uses are now discontinued.

Naphthalene sulfanate is a very effective anyonic for dyes and pigments. 
Naphthalene  shows low cost properties, has good heat stability. 
Naphthalene  has a high pitch against acids and alkalis. 
Naphthalene  is used for naphthalene sulphonates and is used for various other dyes and as a leveling agent. 
Perfect ornament. Naphthalene sulfanate is good for extensive breeding.

Special with a dispersion machine, good leveling in a small amount and good absorption of dyes and pigments from all kinds of things. 
Naphthine sulfanate is stable above 100 oC. 
Naphthalene sulfanate maintains broad pH appearance, pH: 2-12 distribution.

Naphthalene is an organic compound with formula C ₁₀H ₈. 
Naphthalene  is the simplest poly-cyclic aromatic hydrocarbon and appears as a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass.

Naphthalene belongs to a group of chemicals called polycyclic aromatic hydrocarbons. 
These chemicals are found in fossil fuels and are also formed as by-products of the combustion of biomass and fossil fuels. 
Naphthalene usually occurs in solid form, but can also be released as a gas to indoor air at room temperature. 
Most of the exposure to naphthalene occurs though breathing air in the home and other buildings.

Indoors, naphthalene is found in consumer and building products such as air fresheners, paints, stains, flooring and carpeting, as well as in some pest control products (mothballs and moth flakes). 
Naphthalene can also be released from combustion sources in the home such as woodstoves and fireplaces, and from cooking. 
Naphthalene  can enter the home from exhaust from vehicles and gas-powered equipment in attached garages, and is found in cigarette smoke.

Naphthalene is a type of polycyclic aromatic hydrocarbon (PAH) and possible carcinogen. 
Naphthalene  is found abundantly in outdoor air with traffic being the largest source. 
Elevated levels of naphthalene are also found in indoor air when mothballs or kitchen stoves burning biomass fuels are used.

Naphthalene is derived from petroleum and biofuel products and is found entirely in a gaseous phase rather than as a particulate. 
Human exposure to naphthalene is primarily through inhalation, although it can be ingested and absorbed through the skin. 
Due to the volatile nature of naphthalene, a box of mothballs can elevate indoor naphthalene levels to levels compatible with mid to upper level occupational exposure, with higher concentrations in smaller apartments or enclosed areas.

A cause of concern is that some Caribbean immigrant families in New York City frequently use mothballs as air fresheners. 
Therefore understanding potential downstream effects of naphthalene exposure has become increasingly relevant. 
The Center is currently conducting studies of the effects of naphthalene in the New York City cohort; the data collection and analysis is still ongoing.

Naphthalene is an organic compound with an identifying odor detectable at low concentrations. 
Naphthalene  is a white crystalline solid and considered the simplest polycyclic aromatic hydrocarbon. 
Ungraded products supplied by Spectrum are indicative of a grade suitable for general industrial use or research purposes and typically are not suitable for human consumption or therapeutic use.

Naphthalene (NAF-thuh-leen) is a white crystalline volatile solid with a characteristic odor often associated with mothballs. 
The compound sublimes (turns from a solid to a gas) slowly at room temperature, producing a vapor that is highly combustible. 
Naphthalene was first extracted from coal tar in 1819 by English chemist and physician John Kidd (1775–1851). 
Coal tar is a brown to black thick liquid formed when soft coal is burned in an insufficient amount of air. 
Naphthalene  consists of a complex mixture of hydrocarbons, similar to that found in petroleum. 
Kidd's extraction of naphthalene was of considerable historic significance because it demonstrated that coal had other important applications than its use as a fuel. 
Naphthalene  could also be utilized as the source of chemical compounds with a host of important commercial and industrial uses. 
Naphthalene's chemical structure was determined by the German chemist Richard August Carl Emil Erlenmeyer (1825–1909). 
Erlenmeyer showed that the naphthalene molecule consists of two benzene molecules joined to each other.

Naphthalene occurs naturally in petroleum and coal tar. 
Naphthalene  is extracted from either by heating the raw material to a temperature of 200°C to 250°C (392°F to 482°F), producing a mixture of hydrocarbons known as middle oil. 
The middle oil is then distilled to separate its individual components from each other, one of which is naphthalene. 
The naphthalene produced in this process is purified by washing it in a strong acid and then in a sodium hydroxide solution and purified by steam distillation.

Naphthalene is either a white solid or a liquid with a strong odor like mothballs and is classified as a semi-volatile organic compound (SVOC). 
Naphthalene is a polycyclic aromatic hydrocarbon (PAH) with a chemical formula of C10H8 (two fused benzene rings). 
Naphthalene is also called white tar, tar camphor, naphthalin, mothballs, and moth flakes. 
Naphthalene is used to make dyes, explosives, toilet deodorants, insecticides, lubricants, PVC piping, and is a potential part of the chemical suite used in natural gas development. 
Naphthalene can dissolve to some extent in water and is normally only weakly attached to soil particles. 
Naphthalene  occurs naturally in crude oil and coal tar and can be found in diesel fuel, jet fuel, gasoline, kerosene, and lubricating oils. 
Naphthalene is one of the least volatile volatile organic compounds (VOCs), but is one of the most volatile polycyclic aromatic (PAH) compounds.

Before starting with the naphthalene, first you need to understand what is an aromatic compound. 
Aromatic compounds are the ring compound that contains a double and single bond in an alternate manner, and follows the huckel rule. 
Let’s come to our main question, what is a naphthalene? 
Naphthalene is an aromatic hydrocarbon, consisting of two or more fused aromatic benzene rings. 
These are polynuclear aromatic hydrocarbons. 
In short, naphthalene is fused with hydrocarbon. 
In this article we have covered the all important points about the naphthalene like use of naphthalene, structure of naphthalene, and resonance in naphthalene.

Naphthalene is the most simple, commonly found, and most water-soluble PAHs in the environment. 
Naphthalene is produced from coal tar fraction by crystallization and distillation.
Naphthalene is often used as dispersants in natural and synthetic rubbers, in the production of naphthalene sulfonate superplasticizers for concrete, in paints, tanning agents in the leather industry, in the production of the insecticide, etc. 
The primary route of human exposure of naphthalene is through the inhalation, especially in the oil refineries, petrol stations, vicinity of heavy traffic, vehicle exhaust, etc. 
Some studies have reported that naphthalene mothball exposure can cause severe hemolytic anemia in glucose 6-phosphate deficient patients .
Various microorganisms belonging from the genera Burkholderia, Alcaligenes, Mycobacterium, Pseudomonas, Polaromonas, Sphingomonas, Rhodococcus, Ralstonia, and Streptomyces have been isolated that utilize naphthalene as the sole source of carbon and energy  
Naphthalene has often been used as a model compound for PAH degradation.
Naphthalene degradation in bacteria is initiated through the enzyme, naphthalene dioxygenase that attacks the aromatic ring and forms dihydrodiol product, cis-(1R, 2S)-dihydronaphthalene (cis-naphthalene dihydrodiol) (Fig. 11.4A). Further, cis-dihydrodiol dehydrogenase catalyzes the dehydrogenation of cis-naphthalene dihydrodiol to 1,2-dihydroxynaphthalene which is subsequently metabolized by ring-opening reaction catalyzed by dioxygenase to 2-hydroxychromene 2-carboxylate. The hydroxychromene is metabolized to salicylate via 2-hydroxybenzalpyruvate and salicylaldehyde. 
Salicylate is further metabolized to central carbon metabolites either via catechol or gentisate 

In the early 1820s, two separate reports described a white solid with a pungent odor derived from the distillation of coal tar. 
In 1821, John Kidd cited these two disclosures and then described many of this substance's properties and the means of its production. 
He proposed the name naphthaline, as it had been derived from a kind of naphtha (a broad term encompassing any volatile, flammable liquid hydrocarbon mixture, including coal tar).
Naphthalene's chemical formula was determined by Michael Faraday in 1826. 
The structure of two fused benzene rings was proposed by Emil Erlenmeyer in 1866, and confirmed by Carl Gräbe three years later.

The hydrocarbon naphthalene is a white solid with characteristic odor and molecular formula C10H8 (Mr 128,173 gmol-1). 
Naphthalene is a bicyclic aromatic compound, i.e. two benzene rings are fused (annulated) sharing two carbon atoms. 
The aromatic π-electron system extends over all ten carbon atoms.

A naphthalene molecule can be viewed as the fusion of a pair of benzene rings. 
(In organic chemistry, rings are fused if they share two or more atoms.)
As such, naphthalene is classified as a benzenoid polycyclic aromatic hydrocarbon (PAH).

The eight carbons that are not shared by the two rings carry one hydrogen atom each. 
For purpose of the standard IUPAC nomenclature of derived compounds, those eight atoms are numbered 1 through 8 in sequence around the perimeter of the molecule, starting with a carbon adjacent to a shared one. 
The shared carbons are labeled 4a (between 4 and 5) and 8a (between 8 and 1).

The molecule is planar, like benzene. Unlike benzene, the carbon–carbon bonds in naphthalene are not of the same length. 
The bonds C1−C2, C3−C4, C5−C6 and C7−C8 are about 1.37 Å (137 pm) in length, whereas the other carbon–carbon bonds are about 1.42 Å (142 pm) long. 
This difference, established by X-ray diffraction, is consistent with the valence bond model in naphthalene and in particular, with the theorem of cross-conjugation. 
This theorem would describe naphthalene as an aromatic benzene unit bonded to a diene but not extensively conjugated to it (at least in the ground state), which is consistent with two of its three resonance structures.

Because of this resonance, the molecule has bilateral symmetry across the plane of the shared carbon pair, as well as across the plane that bisects bonds C2-C3 and C6-C7, and across the plane of the carbon atoms. 
Thus there are two sets of equivalent hydrogen atoms: the alpha positions, numbered 1, 4, 5, and 8, and the beta positions, 2, 3, 6, and 7. 
Two isomers are then possible for mono-substituted naphthalenes, corresponding to substitution at an alpha or beta position. 
Bicyclo[6.2.0]decapentaene is a structural isomer with a fused 4–8 ring system and azulene is another, with a fused 5-7 ring system.

Pure crystalline naphthalene is a moderate insulator at room temperature, with resistivity of about 1012 Ω m. 
The resistivity drops more than a thousandfold on melting, to about 4 × 108 Ω m. 
Both in the liquid and in the solid, the resistivity depends on temperature as ρ = ρ0 exp(E/(k T)), where ρ0 (Ω m) and E (eV) are constant parameters, k is Boltzmann's constant (8.617×10−5 eV/K), and T is absolute temperature (K). 
The parameter E is 0.73 in the solid. However, the solid shows semiconducting character below 100 K

In electrophilic aromatic substitution reactions, naphthalene reacts more readily than benzene. 
For example, chlorination and bromination of naphthalene proceeds without a catalyst to give 1-chloronaphthalene and 1-bromonaphthalene, respectively. 
Likewise, whereas both benzene and naphthalene can be alkylated using Friedel–Crafts reactions, naphthalene can also be easily alkylated by reaction with alkenes or alcohols, using sulfuric or phosphoric acid catalysts.

In terms of regiochemistry, electrophiles attack at the alpha position. 
The selectivity for alpha over beta substitution can be rationalized in terms of the resonance structures of the intermediate: 
for the alpha substitution intermediate, seven resonance structures can be drawn, of which four preserve an aromatic ring. 
For beta substitution, the intermediate has only six resonance structures, and only two of these are aromatic. 
Sulfonation gives the "alpha" product naphthalene-1-sulfonic acid as the kinetic product but naphthalene-2-sulfonic acid as the thermodynamic product. 
The 1-isomer forms predominantly at 25 °C, and the 2-isomer at 160 °C. 
Sulfonation to give the 1- and 2-sulfonic acid occurs readily:

H2SO4 + C10H8 → C10H7−SO3H + H2O

Further sulfonation give di-, tri-, and tetrasulfonic acids.

Analogous to the synthesis of phenyllithium is the conversion of 1-bromonathalene to 1-lithionaphthalene, by lithium–halogen exchange:

C10H7Br + BuLi → C10H7Li + BuBr

The resulting lithionaphthalene undergoes a second lithiation, in contrast to the behavior of phenyllithium. 
These 1,8-dilithio derivatives are precursors to a host of peri-naphthalene derivatives

With alkali metals, naphthalene forms the dark blue-green radical anion salts such as sodium naphthalene, Na+C10H−8. 
The naphthalene anions are strong reducing agents.

Naphthalene can be hydrogenated under high pressure in the presence of metal catalysts to give 1,2,3,4-tetrahydronaphthalene(C10H12), also known as tetralin. 
Further hydrogenation yields decahydronaphthalene or decalin (C10H18).

Oxidation with O2 in the presence of vanadium pentoxide as catalyst gives phthalic anhydride:

C10H8 + 4.5 O2 → C6H4(CO)2O + 2 CO2 + 2 H2O

This reaction is the basis of the main use of naphthalene. 
Oxidation can also be effected using conventional stoichiometric chromate or permanganate reagents.

Naphthalene is used mainly as a precursor to other chemicals. 
The single largest use of naphthalene is the industrial production of phthalic anhydride, although more phthalic anhydride is made from o-xylene. 
Many azo dyes are produced from naphthalene, and so is the insecticide 1-naphthyl-N-methylcarbamate (carbaryl). 
Other useful agrichemicals include naphthoxyacetic acids.

Many Naphthalene  acids and sulfonates are useful. 
Alkyl naphthalene sulfonate are surfactants, The aminonaphthalenesulfonic acids, naphthalenes substituted with ethers and sulfonic acids, are intermediates in the preparation of many synthetic dyes. 
The hydrogenated naphthalenes tetrahydronaphthalene (tetralin) and decahydronaphthalene (decalin) are used as low-volatility solvents. 
Naphthalene sulfonic acids are also used in the synthesis of 1-naphthol and 2-naphthol, precursors for various dyestuffs, pigments, rubber processing chemicals and other chemicals and pharmaceuticals.

Naphthalene sulfonic acids are used in the manufacture of naphthalene sulfonate polymer plasticizers (dispersants), which are used to produce concrete and plasterboard (wallboard or drywall). 
They are also used as dispersants in synthetic and natural rubbers, and as tanning agents (syntans) in leather industries, agricultural formulations (dispersants for pesticides), dyes and as a dispersant in lead–acid battery plates.

Naphthalene sulfonate polymers are produced by treating naphthalenesulfonic acid with formaldehyde, followed by neutralization with sodium hydroxide or calcium hydroxide. 
These products are commercially sold as superplasticizers for the production of high strength concrete.

Molten naphthalene provides an excellent solubilizing medium for poorly soluble aromatic compounds. 
In many cases it is more efficient than other high-boiling solvents, such as dichlorobenzene, benzonitrile, nitrobenzene and durene. 
The reaction of C60 with anthracene is conveniently conducted in refluxing naphthalene to give the 1:1 Diels–Alder adduct.
The aromatization of hydroporphyrins has been achieved using a solution of DDQ in naphthalene.

Naphthalene has been used as a household fumigant. 
Naphthalene  was once the primary ingredient in mothballs, although its use has largely been replaced in favor of alternatives such as 1,4-dichlorobenzene. 
In a sealed container containing naphthalene pellets, naphthalene vapors build up to levels toxic to both the adult and larval forms of many moths that attack textiles. 
Other fumigant uses of naphthalene include use in soil as a fumigant pesticide, in attic spaces to repel animals and insects, and in museum storage-drawers and cupboards to protect the contents from attack by insect pests.

Naphthalene is a repellent to opossums.

Naphthalene  is used in pyrotechnic special effects such as the generation of black smoke and simulated explosions.
Naphthalene  is used to create artificial pores in the manufacture of high-porosity grinding wheels. 
In the past, naphthalene was administered orally to kill parasitic worms in livestock. 
Naphthalene and its alkyl homologs are the major constituents of creosote. 
Naphthalene is used in engineering to study heat transfer using mass sublimation.

Naphthalene  has been proposed as an alternative propellant for cold gas satellite thrusters

Naphthalene is used in the production of phthalic anhydride; it is also used in mothballs.  
Acute (shortterm) exposure of humans to naphthalene by inhalation, ingestion, and dermal contact is associated with hemolytic anemia, damage to the liver, and neurological damage.  
Cataracts have also been reported in workers acutely exposed to naphthalene by inhalation and ingestion.  
Chronic (long-term) exposure of workers and rodents to naphthalene has been reported to cause cataracts and damage to the retina. 
Hemolytic anemia has been reported in infants born to mothers who "sniffed" and ingested naphthalene (as mothballs) during pregnancy.  
Available data are inadequate to establish a causal relationship between exposure to naphthalene and cancer in humans.  
EPA has classified naphthalene as a Group C, possible human carcinogen.

Naphthalene is used in the production of phthalic anhydride; it is also used in mothballs.
Other uses of naphthalene include 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.

IUPAC NAME:

Bicyclo[4.4.0]deca-1,3,5,7,9-pentene
 
bicyclo[4.4.0]deca-1,3,5,7,9-pentene
 
Naphtalene
 
naphtalene
 
NAPHTHALENE
 
Naphthalene
 
naphthalene
 
Naphthalene

SYNONYM:

Naphthalene  
1421310  
202-049-5  
91-20-3  
Albocarbon
MFCD00001742  
Naftaleen  
Naftalen  
Naftalene  
naftaleno