# | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z |

Name Description
id 70
T3DB ID T3D0078
Name Naphthalene
Class SmallMolecule
Description Naphthalene is the simplest polyaromatic hydrocarbon (PAH) consisting of two fused benzene rings. It has a distinct, pungent odor that can be detected at levels as low as 0.08 ppm. Naphthalene is the most abundant single component of coal tar so most of it is now industrially derived from coal tar. From the 1960s until the 1990s, significant amounts of naphthalene were also produced from heavy petroleum fractions during petroleum refining, but today petroleum-derived naphthalene represents only a minor component of naphthalene production. Naphthalene is also produced naturally with trace amounts of naphthalene being produced by black walnuts, magnolias and specific types of deer, as well as the Formosan subterranean termite. Some strains of the endophytic fungus (Muscodor albus) also produce naphthalene. Naphthalene and other polycyclic aromatic hydrocarbons (PAHs) are released from incomplete combustion processes originating in industry, cigarette smoke and motor vehicle exhaust, as well as natural events such as forest fires. Industrially, naphthalene is used in the production of phthalic anhydride, as a solvent for chemical reactions, as a wetting agent and as a fumigant. It is also used in pyrotechnic special effects such as the generation of black smoke and simulated explosions. In the past, naphthalene was administered orally to kill parasitic worms in livestock. Naphthalene was once the primary ingredient in mothballs, though 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 that are toxic to both the adult and larval forms of many moths. Naphthalene has been shown to exhibit apoptotic and catabolic functions (4, 5). Exposure to large amounts of naphthalene may damage or destroy red blood cells. Humans, in particular children, have developed this condition, known as hemolytic anemia, after ingesting mothballs or deodorant blocks containing naphthalene.
Categories "Household Toxin", "Industrial/Workplace Toxin", "Pollutant", "Airborne Pollutant", "Food Toxin", "Natural Toxin"
Types "Organic Compound", "Aromatic Hydrocarbon", "Industrial By-product/Pollutant", "Polycyclic Aromatic Hydrocarbon", "Pollutant", "Food Toxin", "Metabolite", "Household Toxin", "Industrial/Workplace Toxin", "Natural Compound"
Synonyms "Albocarbon", "Camphor tar", "Moth balls", "Moth flakes", "Mothballs", "Naftalen", "Naphtalene", "Naphthalin", "Naphthaline", "Naphthene", "Tar camphor", "Tolboxane", "White tar"
CAS Number 91-20-3
Chemical Formula C10H8
Average Molecular Mass 128.17
Monoisotopic Mass 128.06
IUPAC Name naphthalene
Traditional Name naphthalene
InChI Identifier InChI=1S/C10H8/c1-2-6-10-8-4-3-7-9(10)5-1/h1-8H
Kingdom Organic Compounds
Super Class Benzenoids
Class Naphthalenes
Sub Class
Direct Parent Naphthalenes
Alternate Parents "Hydrocarbons"
Geometric Description Aromatic Homopolycyclic Compounds
Substituents "naphthalene", "Aromatic Homopolycyclic Compound", "Hydrocarbon"
Descriptors "an aromatic compound (MetaCyc)", "naphthalenes (ChEBI)", "ortho-fused bicyclic arene (ChEBI)", "Fumigants (KEGG)"
Status Detected and Not Quantified
Origin Exogenous
Cellular Locations "Membrane"
State Solid
Appearance White crystals.
Melting Point 80.3°C
Boiling Point 218°C (424.4°F)
Solubility 0.031 mg/mL at 25°C
LogP 3.3
Route of Exposure Oral (L10); inhalation (L10)
Mechanism of Toxicity PAH's such as naphthalene are transported throughout the body after binding blood proteins such as albumin. Binding to the aryl hydrocarbon receptor or glycine N-methyltransferase induces the expression of cytochrome P450 enzymes (especially CYP1A1, CYP1A2, and CYP1B1). These cytochrome enzymes metabolize PAH's into various toxic intermediates (epoxide intermediates, dihydrodiols, phenols, quinones, and their various combinations). The reactive metabolites of PAHs covalently bind to DNA and other cellular macromolecules, initiating mutagenesis and carcinogenesis. (10, 12, 2, 3). In humans, the metabolite alpha-naphthol has been linked to the development of hemolytic anemia in some cases following ingestion or extensive dermal or inhalation exposure. Susceptibility appears to be exacerbated by a deficiency in the glucose 6-phosphate dehydrogenase enzyme, or G-6-PD. Over 400 million people have an inherited condition called glucose-6-phosphate dehydrogenase deficiency. Exposure to naphthalene is more harmful for these people and may cause hemolytic anemia at lower doses. Some naphthalene metabolites deplete glutathione stores in affected tissues such as the lungs, leading to toxicity. The metabolites responsible for glutathione depletion have been identified as naphthalene oxide or 1,2-naphthoquinone and 1,4-naphthoquinone.
Metabolism PAH metabolism occurs in all tissues, usually by cytochrome P-450 and its associated enzymes. PAHs are metabolized into reactive intermediates, which include epoxide intermediates, dihydrodiols, phenols, quinones, and their various combinations. The phenols, quinones, and dihydrodiols can be conjugated to glucuronides and sulfate esters; and the quinones can form glutathione conjugates. (L10)
Toxicity LD50: 490 mg/kg (Oral, Rat) (T29) LD50: >20 g/kg (Dermal, Rabbit) (T29) LD50: 150 mg/kg (Intraperitoneal, Mouse) (T14) LD50: 969 mg/kg (Subcutaneous, Mouse) (T14) LD50: 100 mg/kg (Intravenous, Mouse) (T14)
Lethal Dose
Carcinogenicity 2B, possibly carcinogenic to humans. (L135)
Uses/Sources Industrially, naphthalene is used in the production of phthalic anhydride, as a solvent for chemical reactions, as a wetting agent and as a fumigant. Naphthalene is produced industrially via coal tar and naturally with trace amounts of naphthalene being produced by black walnuts, magnolias and specific types of deer.
Minimum Risk Level
Health Effects Inhalation of naphthalene vapor has been associated with headaches, nausea, vomiting and dizziness. Hemolysis, the abnormal breakdown of red blood cells, may occur following ingestion or sufficient dermal exposure to either naphthalene or to naphthalene-treated fabric. In humans, cataracts and other ocular injury have been reported following acute and chronic occupational exposure to naphthalene. Additional signs of toxicity in children include convulsions and coma. Infants may develop encephalopathy and kernicterus, a form of brain damage, due to the presence of increased levels of methemoglobin, hemoglobin, and bilirubin in their plasma. Naphthalene appears to be mildly carcinogenic. Rats exposed to naphthalene vapors at 10, 30, or 60 ppm for 6 hours a day, five days a week for two years developed respiratory epithelial adenomas and olfactory epithelial neuroblastomas.
Symptoms Symptoms of hemolytic anemia include fatigue, lack of appetite, restlessness, and pale skin. Exposure to large amounts of naphthalene may cause confusion, nausea, vomiting, diarrhea, blood in the urine, and jaundice (yellow coloration of the skin).
Treatment There is no known antidote for PAHs. Exposure is usually handled with symptomatic treatment. (L10)
DrugBank ID
PubChem Compound ID 931
ChemSpider ID 906
KEGG Compound ID C00829
UniProt ID 0
ChEBI ID 16482
CTD ID C031721
Stitch ID Naphthalene
ACToR ID 934
Wikipedia Link http://en.wikipedia.org/wiki/Naphthalene
Creation Date 2009-03-06 18:58:02
Update Date 2014-12-24 20:21:03