Camphor

From Plastics Wiki, free encyclopedia

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.

Modern uses include as a plasticizer for cellulose nitrate, as a moth repellent, as an antimicrobial substance, in embalming, and in fireworks. 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 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.

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

The word camphor derives from the Malay word kapur, meaning "camphor tree" [1].

Camphor was the 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.

Reactions

Image:Camphor-3-Brominecampher.png Image:Camphor-Camphor acid.png Image:Camphor-Isonitrosocamphor.png

Camphor can also be reduced to isoborneol using sodium borohydride.

Biosynthesis

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

References

1. 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 0582060095.
2. Handbook of Chemistry and Physics, CRC Press, Ann Arbor, Michigan.
3. The Merck Index, 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.