Naphthalene

Naphthalene

Mothballs containing naphthalene
Names
IUPAC name Naphthalene
Preferred IUPAC name Naphthalene
Systematic IUPAC name Bicyclo[4.4.0]deca-1,3,5,7,9-pentaene Bicyclo[4.4.0]deca-2,4,6,8,10-pentaene
Other names Camphor tar Naphthalin White tar
Identifiers
Jmol-3D images	Image
SMILES c1ccc2ccccc2c1
Properties
Chemical formula	C10H8
Molar mass	128.17 g/mol
Appearance	White volatile solid
Odor	Strong, aromatic
Density	1.145 g/cm3 (15.5 °C) 1.0253 g/cm3 (20 °C) 0.9625 g/cm3 (100 °C)
Melting point	80.2 °C (176.4 °F; 353.3 K)
Boiling point	217.9 °C (424.2 °F; 491.0 K)
Solubility in water	0.00190 g/100 ml (10 °C) 0.00316 g/100 ml (25 °C) 0.00439 g/100 ml (34.5 °C) 0.00809 g/100 ml (50 °C) 0.02381 g/100 ml (73.4 °C)
Solubility	Soluble in glacial acetic acid, liq. ammonia, aniline, benzene, CS2, CCl4, ethanol, olive oil, liq. SO2, toluene, turpentine
Solubility in acetic acid	6.8 g/100 g (6.75 °C) 13.1 g/100 g (21.5 °C) 31.1 g/100 g (42.5 °C) 111 g/100 g (60 °C)
Solubility in butyric acid	13.6 g/100 g (6.75 °C) 22.1 g/100 g (21.5 °C) 131.6 g/100 g (60 °C)
Solubility in carbon disulfide	83.3 g/100 ml
Solubility in chloroform	19.5 g/100 g (0 °C) 35.5 g/100 g (25 °C) 49.5 g/100 g (40 °C) 87.2 g/100 g (70 °C)
Solubility in ethanol	5 g/100 g (0 °C) 11.3 g/100 g (25 °C) 19.5 g/100 g (40 °C) 179 g/100 g (70 °C)
Vapor pressure	8.64 Pa (20 °C) 23.6 Pa (30 °C) 0.93 kPa (80 °C) 2.5 kPa (100 °C)
Viscosity	0.964 cP (80 °C) 0.761 cP (100 °C) 0.217 cP (150 °C)
Thermochemistry
Std molar entropy (So298)	167.39 J·mol-1·K-1
Std enthalpy of formation (ΔfHo298)	78.53 kJ/mol
Hazards
Safety data sheet	Sigma-Aldrich
Flash point	80 °C
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	1800 mg/kg (rat, oral) 490 mg/kg (rat, oral) 1200 mg/kg (guinea pig, oral) 533 mg/kg (mouse, oral)
Related compounds
Related compounds	Tetralin Decalin
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Naphthalene is an organic compound with the chemical formula C₁₀H₈. It is the simplest polycyclic aromatic hydrocarbon.

Properties

Chemical

Naphthalene can react with halogens, such as chlorine to form 1-chloronaphthalene, without requiring a catalyst, unlike in the case of benzene. Likewise, whereas both benzene and naphthalene can be alkylated using Friedel–Crafts reactions, naphthalene can also be alkylated by reaction with alkenes or alcohols, with sulfuric or phosphoric acid as the catalyst.

Physical

Naphthalene is a white crystalline solid with a characteristic odor that is detectable at low concentrations. It is insoluble in water, but soluble in other organic solvents, especially closer to their boiling point.

Availability

Some mothballs, especially the older types tend to contain naphthalene, the exact concentration depending on the product. Naphthalene can be extracted via sublimation. Always check the label, as most common mothballs contain 1,4-dichlorobenzene.

Naphthalene and 1,4-dichlorobenzene are never found together, as they react.

Mothballs and other products containing naphthalene have been banned within the EU since 2008. However, you may still find naphthalene powder/balls in some second-hand hardware stores, as "odor pellets". The naphthalene content is between 80-95 % and the impurities sometimes render the naphthalene non-flammable.

Preparation

Naphthalene can be extracted from coal tar, via sublimation and purification.

Projects

• Phthalic anhydride synthesis
• Dialin synthesis

Handling

Safety

Naphthalene is known to be toxic to red blood cells and it's considered a possible carcinogenic. Its strong smell is considered obnoxious and it's best to handle it outside or in a well ventilated area (like a fume hood).

Storage

Naphthalene should be stored in hermetically sealed bottles and kept in a cold place as it will slowly sublime and deposit on the cap interior. Instant coffee and paint cans are good storage containers.

Disposal

Burning naphthalene is an attractive disposal method, but will result in lots of soot, VOCs, PAHs, other aromatics, carbon monoxide, as well as fumes of unburnt naphthalene being generated. The resulting smoke has a strong smell, like in the case of most aromatics, and burning may not be a suitable method of disposal in a densely populated area. While this is not an issue with small amounts, a special incinerator may be required for bulk quantities.

It can also be destroyed with Fenton's reagent. However, the heat of the oxidation may give off various side products, so neutralize small amounts, outside. A UV lamp can be used to improve the Fenton oxidation process.

Gallery

• 

  Sublimated naphthalene crystals under the microscope

References

Relevant Sciencemadness threads

• Naphthalene Reactions
• solubility of naphthalene in acetone
• When naphthalene balls aren’t naphthalene balls(?)
• Naphthalene storage