Camphor

Camphor
IUPAC name	1,7,7-trimethylbicyclo [2.2.1]heptan-2-one
Other names	2-bornanone, 2-camphanone bornan-2-one, Formosa
Identifiers
CAS number	[76-22-2] (unspecified) [464-49-3] ((1R)-Camphor) [464-48-2] ((1S)-Camphor}
RTECS number	EX1260000 (R) EX1250000 (S)
SMILES	O=C1CC2CCC1(C)C2(C)(C)
Properties
Molecular formula	C10H16O
Molar mass	152.23
Appearance	White or colorless crystals
Density	0.990 (solid)
Melting point	179.75 °C (452.9 K)
Boiling point	204 °C (477 K)
Solubility in water	0.12 g in 100 ml
Solubility in chloroform	~100 g in 100 ml
Chiral rotation [α]D	+44.1°
Hazards
Main hazards	flammable
NFPA 704	2 2 0
R-phrases	11-20/21/22-36/37/38
S-phrases	16-26-36
Related Compounds
Related ketone	fenchone,thujone
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Camphor is a waxy, white or transparent solid with a strong, aromatic odor. Chemically, it is classified as a terpenoid, and its chemical formula is C₁₀H₁₆O. It is found in the bark and wood of the camphor laurel (Cinnamonum camphora), a large evergreen tree found in Asia (particularly, Borneo and Taiwan). It also occurs in some other related trees of the laurel family, notably Ocotea usambarensis. It can also be synthetically produced from oil of turpentine. It is used for its scent, as an ingredient in cooking (mainly in India), as an embalming fluid, in religious ceremonies and for medicinal purposes. A major source of camphor in Asia is camphor basil.

Etymology and history

The word camphor derives from the French word camphre, itself from Medieval Latin camfora, from Arabic kafur, from Malay kapur Barus meaning "Barus chalk". In fact Malay traders from whom Indian and Middle East merchants would buy camphor called it kapur, "chalk" because of its white color. Barus was the port on the western coast of the Indonesian island of Sumatra where foreign traders would call to buy camphor. In the Indian language Sanskrit, the word karpoor is used to denote Camphore. An adaptation of this word, karpooram, has been used for camphor in many South Indian (Dravidian) languages, such as Telugu, Tamil, Kannada, and Malayalam.

Camphor was first synthesized by Gustaf Komppa in 1903. Previously, some organic compounds (such as urea) had been synthesized in the laboratory as a proof of concept, but camphor was a scarce natural product with a worldwide demand. The synthesis was the first industrial total synthesis, when Komppa began industrial production in Tainionkoski, Finland, in 1907.

Norcamphor is a camphor derivative with the three methyl groups replaced by hydrogen atoms.

Other substances derived from trees are sometimes wrongly sold as camphor.

Uses

Modern uses include as a plasticizer for Nitrocellulose, as a moth repellent, as an antimicrobial substance, in embalming, and in fireworks. Solid camphor releases fumes that form a rust-preventative coating and is therefore stored in tool chests to protect tools against rust. Camphor crystals are also used to prevent damage to insect collections by other small insects.

It is also used in medicine. Camphor is readily absorbed through the skin and produces a feeling of cooling similar to that of menthol and acts as slight local anesthetic and antimicrobial substance. A form of anti-itch gel currently on the market uses camphor as its active ingredient. Camphor is an active ingredient (along with menthol) in vapor-steam products, such as Vicks VapoRub, and it is effective as a cough suppressant. It may also be administered orally in small quantities (50 mg) for minor heart symptoms and fatigue.

In the 18th Century, it was used by Auenbrugger in the treatment of mania.^{[citation needed]}

It is also believed that camphor will deter snakes and other reptiles due to its strong odor. Similarly, camphor is believed to be toxic to insects and is thus sometimes used as a repellent.^{[citation needed]}

Camphor is also used in the Mahashivratri celebrations of Shiva, the Hindu god of destruction and re-creation. As a natural pitch substance it burns cool without leaving an ash residue, which symbolizes consciousness.

It is also found in clarifying masks used for skin.

Recently, carbon nanotubes were successfully synthesized using camphor in chemical vapor deposition process.

Culinary

Currently, camphor is mostly used as a flavoring for sweets in Asia. In ancient and medieval Europe it was widely used as ingredient for sweets but it is now mainly used for medicinal purposes. Camphor was used as a flavoring in confections resembling ice cream in China during the Tang dynasty (A.D. 618-907).^{[citation needed]} Camphor is widely used in cooking (mainly for dessert dishes) in India where it is known as Pachha Karpooram (literally meaning "green camphor" though "Pachha" in Tamil can also be translated to mean "raw" which is "Pachha Karpooram's" intended meaning). It is widely available at Indian grocery stores and is labeled as "Edible Camphor." In Hindu poojas and ceremonies, camphor is burned in a ceremonial spoon for performing aarti. This type of camphor is also sold at Indian grocery stores but it is not suitable for cooking. The only type that should be used for food are those which are labeled as "Edible Camphor."

Toxicology

In larger quantities, it is poisonous when ingested and can cause seizures, confusion, irritability, and neuromuscular hyperactivity. In 1980, the United States Food and Drug Administration set a limit of 11% allowable camphor in consumer products and totally banned products labeled as camphorated oil, camphor oil, camphor liniment, and camphorated liniment (but "white camphor essential oil" contains no significant amount of camphor). Since alternative treatments exist, medicinal use of camphor is discouraged by the FDA, except for skin-related uses, such as medicated powders, which contain only small amounts of camphor. Lethal doses in adults are in the range 50–500 mg/kg (orally). Generally, 2 g causes serious toxicity and 4 g is potentially lethal.

Reactions

Typical camphor reactions are:

• bromination

• oxidation with nitric acid

• conversion to isonitrosocamphor

Camphor can also be reduced to isoborneol using sodium borohydride.

Biosynthesis

In biosynthesis camphor is produced from geranyl pyrophosphate, via cyclisation of linaloyl pyrophosphate to bornyl pyrophosphate, followed by hydrolysis to borneol and oxidation to camphor.

See also

• Isoprene
• Terpene

References

ISBN links support NWE through referral fees

• Lide, David R., ed. 2007. CRC Handbook of Chemistry and Physics. 88th ed. Boca Raton, FL: CRC. ISBN 978-0849304880.

• Mann, J., et al. 1994. Natural Products: Their Chemistry and Biological Significance. Harlow, Essex, UK: Longman Scientific & Technical. ISBN 0582060095.

• O'Neil, Maryadele J., ed. 2006. The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals. 14th ed. Whitehouse Station, NJ: Merck. ISBN 978-0911910001.

• Sell, Charles. 2003. A Fragrant Introduction to Terpenoid Chemistry. Cambridge: Royal Society of Chemistry. ISBN 978-0854046812.

• Smith, Michael, and Jerry March. 2001. March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. 5th ed. New York: Wiley. ISBN 978-0471585893.

External links

• Camphor. Natural Medicines Comprehensive Database. Retrieved June 11, 2008.

• What is Camphor? wiseGEEK. Retrieved June 11, 2008.

• Camphor. 3Dchem.com. Retrieved June 11, 2008.

• Camphor. Natural Medicines Comprehensive Database. Retrieved June 11, 2008.

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