Naphthalene
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Naphthalene is an organic compound with the chemical formula C10H8. It is the simplest polycyclic aromatic hydrocarbon.
Contents
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
- Phtalic anhydride synthesis
- Dialin synthesis
Handling
Safety
Naphthalene is known to to be toxic to red blood cells and it's considered a possible carcinogenic.
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 unburnt naphtalene. 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.
