Camphor is a white transparent waxy crystalline solid with a strong penetrating pungent aromatic odor. It is a terpenoid with the chemical formula C₁₀H₁₆O. It is found in wood of the camphor laurel (Cinnamonum camphora), a large evergreen tree found in Asia (particularly in Borneo, hence its alternate name) and some other related trees in the laurel family, notably Ocotea usambarensis; it can also be synthetically produced from oil of turpentine. It is used for its scent, as an embalming fluid and for medicinal purposes. A major source of camphor in Asia is Camphor basil.

1 History
2 Uses
3 Toxicology
4 Reactions
5 Biosynthesis
6 References
7 External links

[edit] 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 colour [1]. 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 'karpooram' is used to denote Camphore. The word 'karpooram' has been used for camphor in many other Indian languages (like 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.

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

[edit] Uses

Modern uses include as a plasticizer for cellulose nitrate, as a moth repellent, as an antimicrobial substance, in embalming, and in fireworks. Camphor crystals are also used to prevent damage to insect collections by other small insects. A form of anti-itch gel currently on the market uses camphor as its active ingredient. 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. It may also be administered orally in small quantities (50 mg) for minor heart symptoms and fatigue. Camphor is also used as a flavoring in sweets in India and Europe. It is thought that camphor was used as a flavouring in confections resembling ice cream in China during the Tang dynasty (A.D. 618-907).

In Hindu poojas, camphor is used to light the fire for aarti.

[edit] 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 camphor is absent in "white camphor essential oil"). 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.

[edit] Reactions

Typical camphor reactions are:

bromination

Image:Camphor-3-Brominecampher.png

oxidation with nitric acid

Image:Camphor-Camphor acid.png

conversion to isonitrosocamphor

Image:Camphor-Isonitrosocamphor.png

Camphor can also be reduced to isoborneol using sodium borohydride.

[edit] 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.

Image:CamphorBiosynthesis.png

[edit] References

J. Mann, R. S. Davidson, J. B. Hobbs, D. V. Banthorpe, J. B. Harborne, Natural Products, pp. 309-311, Addison Wesley Longman Ltd., Harlow, UK, 1994. ISBN 0-582-06009-5.
Handbook of Chemistry and Physics, CRC Press, Ann Arbor, Michigan.
The Merck Index, 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.