Naphthalene

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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
Properties
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)
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
167.39 J·mol-1·K-1
78.53 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point 80 °C
Lethal dose or concentration (LD, LC):
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 naphtalene, 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

Handling

Safety

Naphthalene is known to 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 hermetic sealed bottles and kept in a cold place as it will slowly sublime and deposit on the cap interior.

Disposal

Burning naphthalene will result in lots of soot, VOCs, PAHs, other aromatics, carbon monoxide, as well as fumes of unburnt naphthalene. 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 dense 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. An UV lamp can be used to improve the Fenton oxidation process.

References

Relevant Sciencemadness threads