| Camphor[1][2] | |
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1,7,7-Trimethylbicyclo[2.2.1]heptan-2-one |
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1,7,7-Trimethylbicyclo[2.2.1]heptan-2-one |
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Other names
2-Bornanone; Bornan-2-one; 2-Camphanone; Formosa |
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| Identifiers | |
| CAS number | 76-22-2 , 464-49-3 (R) , 464-48-2 (S) |
| PubChem | 2537, 9543187 (R), 10050 (S) |
| ChemSpider | 2441 , 7822160 (R) , 9655 (S) |
| UNII | 5TJD82A1ET |
| EC number | 200-945-0 |
| UN number | 2717 |
| DrugBank | DB01744 |
| KEGG | D00098 |
| MeSH | Camphor |
| ChEBI | CHEBI:36773 |
| ChEMBL | CHEMBL15768 |
| IUPHAR ligand | 2422 |
| RTECS number | EX1225000 |
| ATC code | C01 |
| Beilstein Reference | 1907611 |
| Gmelin Reference | 83275 |
| 3DMet | B04729 |
| Jmol-3D images | Image 1 Image 2 |
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| Properties | |
| Molecular formula | C10H16O |
| Molar mass | 152.23 g mol−1 |
| Exact mass | 152.120115134 g mol−1 |
| Appearance | White, translucent crystals |
| Density | 0.990 g cm−3 |
| Melting point |
175-177 °C, 448-450 K, 347-351 °F |
| Boiling point |
204 °C, 477 K, 399 °F |
| Solubility in water | 1.2 g dm−3 |
| Solubility in acetone | ~2500 g dm−3 |
| Solubility in acetic acid | ~2000 g dm−3 |
| Solubility in diethyl ether | ~2000 g dm−3 |
| Solubility in chloroform | ~1000 g dm−3 |
| Solubility in ethanol | ~1000 g dm−3 |
| log P | 2.089 |
| Vapor pressure | 4 mmHg (at 70 °C) |
| Chiral rotation [α]D | +44.1° |
| Hazards | |
| EU classification | F Xn |
| R-phrases | R11 R22 R36/37/38 |
| S-phrases | S16 S26 |
| NFPA 704 |
2
2
0
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| Flash point | 64 °C |
| Explosive limits | 3.5% |
| Related compounds | |
| Related Ketones | Fenchone, Thujone |
| Related compounds | Camphene, Pinene, Borneol, Isoborneol, Camphorsulfonic acid |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Camphor is a waxy, white or transparent solid with a strong, aromatic odor.[3] It is a terpenoid with the chemical formula C10H16O. It is found in wood of the camphor laurel (Cinnamomum camphora), a large evergreen tree found in Asia (particularly in Borneo and Taiwan) and also of Dryobalanops aromatica, a giant of the Bornean forests. It also occurs in some other related trees in the laurel family, notably Ocotea usambarensis. Dried rosemary leaves (Rosmarinus officinalis), in the mint family, contain up to 20% camphor. 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, for medicinal purposes, and in religious ceremonies. A major source of camphor in Asia is camphor basil.
Norcamphor is a camphor derivative with the three methyl groups replaced by hydrogen.
Contents |
The word camphor derives from the French word camphre, itself from Medieval Latin camfora, from Arabic kafur, from Sanskrit, karpuura.[4] Barus was the port on the western coast of the Indonesian island of Sumatra where foreign traders would call to buy camphor, hence in Malay it became kapur Barus. Camphor was known in Arabia in pre-Islamic times, as it is mentioned in the Quran 76:5 as a flavoring for drinks. In the 9th century, the Arab chemist, Al-Kindi (known as Alkindus in Europe), provided the earliest recipe for the production of camphor in his Kitab Kimiya' al-'Itr (Book of the Chemistry of Perfume). By the 13th century, it was used in recipes everywhere in the Muslim world, ranging from main dishes such as tharid and stew to desserts.[5]
Already in the 19th century, it was known that with nitric acid, camphor could be oxidized into camphoric acid. Haller and Blanc published a semisynthesis of camphor from camphoric acid, which, although demonstrating its structure, would not prove it. The first complete total synthesis for camphoric acid was published by Gustaf Komppa in 1903. Its starting materials were diethyl oxalate and 3,3-dimethylpentanoic acid, which reacted by Claisen condensation to give diketocamphoric acid. Methylation with methyl iodide and a complicated reduction procedure produced camphoric acid. William Perkin published another synthesis a short time later. 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. Komppa realized this and began industrial production of camphor in Tainionkoski, Finland, in 1907.
Camphor can be produced from alpha-pinene, which is abundant in the oils of coniferous trees and can be distilled from turpentine produced as a side product of chemical pulping. With acetic acid as the solvent and with catalysis by a strong acid, alpha-pinene readily rearranges into camphene, which in turn undergoes Wagner-Meerwein rearrangement into the isobornyl cation, which is captured by acetate to give isobornyl acetate. Hydrolysis into isoborneol followed by oxidation gives camphor.
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.
Typical camphor reactions are
Camphor can also be reduced to isoborneol using sodium borohydride.
In 2007, carbon nanotubes were successfully synthesized using camphor in chemical vapor deposition process.[6]
Modern uses include camphor as a plasticizer for nitrocellulose (see Celluloid), 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.[7]
Camphor crystals are also used to prevent damage to insect collections by other small insects, also as a cough Suppressant. Some folk remedies state 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.[8]
In ancient and medieval Europe, camphor was used as an ingredient in sweets. It was also used as a flavoring in confections resembling ice cream in China during the Tang dynasty (AD 618–907). It was used in a wide variety of both savory and sweet dishes in medieval Arabic language cookbooks, such as al-Kitab al-Ṭabikh compiled by ibn Sayyâr al-Warrâq in the 10th century,[9] and an anonymous Andalusian cookbook of the 13th century.[10] It also appears in sweet and savory dishes in a book written in the late 15th century for the sultans of Mandu, the Ni'matnama.[11]
Currently, camphor is used as a flavoring, mostly for sweets, in Asia. It is widely used in cooking, mainly for dessert dishes, in India where it is known as kachha karpooram ("crude/raw camphor"), in Tamil:பச்சைக் கற்பூரம்), and is available in Indian grocery stores where it is labeled as "Edible Camphor". But in Tamil, rasak karpooram is entirely different and toxic.
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. There are anti-itch gels and cooling gels with camphor as the active ingredient. Camphor is an active ingredient (along with menthol) in vapor-steam products, such as Vicks VapoRub. Although touted as a cough suppressant, it has no effects on respiratory tract function. A recent publication in Pediatrics suggests the topical application of VapoRub may improve symptoms of colds and sleep quality when compared to a control.[12]
Camphor may also be administered orally in small quantities (50 mg) for minor heart symptoms and fatigue.[13] Through much of the 1900s this was sold by the trade name Musterole, production ceased in the 1990's.
In the 18th century, camphor was used by Auenbrugger in the treatment of mania.[14]
Camphor is widely used in Hindu religious ceremonies. Hindus worship a holy flame by burning camphor, which forms an important part of many religious ceremonies. Camphor is 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. Of late, most temples in southern India have stopped lighting camphor in the main Sanctum Sanctorum because of the heavy carbon deposits it produces; however, open areas still burn it.
In Hindu pujas and ceremonies, camphor is burned in a ceremonial spoon for performing aarti. This type of camphor, the processed white crystalline kind, is also sold at Indian grocery stores. It is not suitable for cooking, however, and is hazardous to health if eaten.
In larger quantities, camphor is poisonous when ingested and can cause seizures, confusion, irritability, and neuromuscular hyperactivity. In extreme cases, even topical application of camphor may lead to hepatotoxicity.[15] [16] Lethal doses in adults are in the range 50–500 mg/kg (orally). Generally, two grams cause serious toxicity and four grams are potentially lethal.[17]
In 1980, the U.S. 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 (except "white camphor essential oil", which 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.