Naphthalene is an organic compound with formula C ₁₀H ₈. It 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. Structurally it consists of two fused benzene rings giving a planar aromatic system; molecular weight 128.17 g mol and CAS 91-20-3. Typical physical properties include a melting point near 80.2 °C, boiling point near 218 °C, solid density about 1.14 g cm3 at 20 °C and limited water solubility around 30 mg L at 25 °C. Naphthalene sublimes readily and has measurable vapor pressure at ambient temperature, which contributes to its volatility. It is produced commercially by distillation of coal tar and by recovery from petroleum fractionation and catalytic reforming, and it is a feedstock for oxidation to phthalic anhydride and for sulfonation to produce naphthalene sulfonates used as dispersants and intermediates. Analytical characterization is routinely done by GC or GC MS for volatile fractions, by HPLC for related heavier aromatics, by IR spectroscopy with aromatic C H stretching near 3050 cm1 and characteristic C C aromatic absorptions near 1600 and 1500 cm1, and by UV visible spectroscopy with strong absorbances in the 220 to 280 nm region; 1H NMR aromatic resonances appear roughly in the 7.4 to 8.5 ppm range.
Commercial grades of naphthalene vary by intended use and purification method; technical grade for industrial applications typically contains the bulk compound at about 95 to 99.5 percent by mass while reagent or electronic grades are purified to greater than 99.9 percent. Typical related hydrocarbons and their approximate concentration ranges in technical material are 1 and 2 methylnaphthalenes 0.2 to 2.0 percent, dimethylnaphthalenes 0.05 to 0.5 percent, acenaphthene and acenaphthylene together commonly below 0.1 to 0.5 percent, fluorene below 0.2 percent, and trace amounts of heavier polycyclics such as phenanthrene and anthracene often at parts per thousand to parts per million levels depending on feedstock. Sulfur containing compounds and other heteroatom residues from coal tar derived material are usually present at ppm levels and are reduced by purification steps; moisture and ash are normally below 0.05 percent in commercial products. Purity specifications and analytical tolerances are typically provided by suppliers and verified by GC, GC MS or HPLC methods.
Yes. Naphthalene is irritating to the eyes and respiratory tract and can cause systemic toxicity after sufficient inhalation or ingestion; it is known to cause hemolytic anemia, particularly in individuals with glucose 6 phosphate dehydrogenase deficiency, and repeated high exposures have been associated with neurological effects and cataract formation in animal studies. International agencies classify naphthalene as a possible human carcinogen based on limited human and sufficient animal evidence, so occupational and consumer exposures are managed by exposure controls, ventilation and regulatory limits.
Direct therapeutic use of naphthalene is limited because of toxicity risk; it has historically been used as a topical antiparasitic and as a component of mothball preparations for pest control rather than a medicinal active ingredient. More commonly naphthalene serves as a chemical intermediate in the synthesis of pharmaceutical building blocks and active compounds where naphthyl moieties are incorporated into drug candidates. In addition naphthalene sulfonates and derivatives are used as excipients and dispersants in formulations.
The accepted common name is simply naphthalene. Older or trade names include naphthalin and sometimes white tar or coal tar camphor when referring to crude materials, and the consumer product containing naphthalene is often called a mothball.
No. Camphor is a distinct natural terpene ketone with formula C10H16O used in topical analgesics and aromatic applications; it is chemically and physically different from naphthalene and should not be considered the same compound.
