Camphor: Difference between revisions
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== Production == |
== Production == |
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[[File:Sublimed camphor.jpg|thumb|left|A sample of camphor]] |
[[File:Sublimed camphor.jpg|thumb|left|A sample of sublimed camphor]] |
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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 [[Rearrangement reaction|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.{{Template:Clearleft}} |
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 [[Rearrangement reaction|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.{{Template:Clearleft}} |
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Revision as of 11:14, 18 April 2012
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| Names | |||
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| IUPAC name
1,7,7-Trimethylbicyclo[2.2.1]heptan-2-one
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| Systematic IUPAC name
1,7,7-Trimethylbicyclo[2.2.1]heptan-2-one | |||
| Other names
2-Bornanone; Bornan-2-one; 2-Camphanone; Formosa
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| Identifiers | |||
3D model (JSmol)
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| 3DMet | |||
| 1907611 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| DrugBank | |||
| ECHA InfoCard | 100.000.860 | ||
| EC Number |
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| 83275 | |||
| KEGG | |||
| MeSH | Camphor | ||
PubChem CID
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| RTECS number |
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| UNII | |||
| UN number | 2717 | ||
CompTox Dashboard (EPA)
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| Properties | |||
| C10H16O | |||
| Molar mass | 152.237 g·mol−1 | ||
| Appearance | White, translucent crystals | ||
| Density | 0.990 g cm−3 | ||
| Boiling point | 204 °C (399 °F; 477 K) | ||
| 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)
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+44.1° | ||
| Hazards | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 64 °C | ||
| Explosive limits | 3.5% | ||
| Related compounds | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.
History
The word camphor derives from the French word [camphre] Error: {{Lang}}: text has italic markup (help), itself from Medieval Latin [camfora] Error: {{Lang}}: text has italic markup (help), from Arabic [kafur] Error: {{Lang}}: text has italic markup (help), from Sanskrit, karpuura.[4] Barus was the name of an early port on a city named "Sibolga" (located in the western coast of Sumatra island - North Sumatra Province, Republic of Indonesia]. At that time, this city was initially built prior to the Indian - Bataknese trade of camphor and spices. Foreign traders such as; Dravidian - Indian, East Asian and Middle east traders would call "kapur barus" to buy the extract/dried ooze of camphor tree from the local tribesman (Bataknese), in [Bataknese language - "Gorga" alphabets|proto malay-austronesian language (Sanskrit adapted-Bataknese alphabets]] it also known as [kapur Barus] Error: {{Lang}}: text has italic markup (help). Until now, the local tribesman and Indonesian in general refer to naphthalene balls and moth balls as [kapur Barus] Error: {{Lang}}: text has italic markup (help). For the local tribesman the use of camphor are ranging from deodorant, wood - cloth finishing veneer coat, traditional ritual and non edible preservatives as the camphor tree itself natively found in that region. The tree itself in Indonesian language called as "Kamfer" (Which also known for it's resistance towards tropical termites).
The sublimate capabilities of camphor is quite similar to alcohol of which in early international trade has made camphor widely 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 "publicity" for the production of camphor in his Kitab Kimiya' al-'Itr (Book of the Chemistry of Perfume).[citation needed] 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.
Production
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.
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.
Biosynthesis of camphor from geranyl pyrophosphate
Reactions
Typical camphor reactions are
- oxidation with nitric acid,
- conversion to isonitrosocamphor.
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]
Uses
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]
Culinary
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).[citation needed] 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 or "pachha karpoora" ("crude/raw camphor"), in (Tamil:பச்சைக் கற்பூரம்), (Kannada:ಪಚ್ಚ ಕರ್ಪೂರ), and is available in Indian grocery stores where it is labeled as "Edible Camphor". But in Tamil, rasak karpooram is entirely different and toxic.
Medicinal
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 under the trade name Musterole; production ceased in the 1990s.
In the 18th century, camphor was used by Auenbrugger in the treatment of mania.[14]
Alternative medicine
Camphor is available as an essential oil for aromatherapy or topical application.
Hindu religious ceremonies
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[when?], 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.
Toxicology
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.
See also
References
- ^ The Merck Index, 7th edition, Merck & Co., Rahway, New Jersey, USA, 1960
- ^ Handbook of Chemistry and Physics, CRC Press, Ann Arbor, Michigan, USA
- ^ Mann JC, Hobbs JB, Banthorpe DV, Harborne JB (1994). Natural products: their chemistry and biological significance. Harlow, Essex, England: Longman Scientific & Technical. pp. 309–11. ISBN 0-582-06009-5.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ Camphor at the Online Etymology Dictionary
- ^ An Anonymous Andalusian cookbook of the 13th century, translated from the original Arabic by Charles Perry
- ^ Kumar M, Ando Y (2007). "Carbon Nanotubes from Camphor: An Environment-Friendly Nanotechnology". J Phys Conf Ser. 61: 643–6. Bibcode:2007JPhCS..61..643K. doi:10.1088/1742-6596/61/1/129.
- ^ Tips for Cabinet Making Shops
- ^ The Housekeeper's Almanac, or, the Young Wife's Oracle! for 1840!. No. 134. New-York: Elton, 1840. Print.
- ^ Nasrallah, Nawal (2007). Annals of the Caliphs' Kitchens: Ibn Sayyâr al-Warrâq's Tenth-century Baghdadi Cookbook. Islamic History and Civilization, 70. Leiden, The Netherlands: Brill. ISBN 978-0-415-35059-4.
- ^ An Anonymous Andalusian cookbook of the 13th century, translated from the original Arabic by Charles Perry
- ^ Titley, Norah (2004). The Ni'matnama Manuscript of the Sultans of Mandu: The Sultan's Book of Delights. Routledge Studies in South Asia. London, UK: Routledge. ISBN 978-0-415-35059-4.
{{cite book}}: Unknown parameter|middle=ignored (help) - ^ Paul, I. M.; Beiler, J. S.; King, T. S.; Clapp, E. R.; Vallati, J.; Berlin, C. M. (2010). "Vapor Rub, Petrolatum, and No Treatment for Children With Nocturnal Cough and Cold Symptoms". Pediatrics. 126 (6): 1092–9. doi:10.1542/peds.2010-1601. PMID 21059712.
- ^ National Agency for Medicines
- ^ Pearce, J M S (2008). "Leopold Auenbrugger: camphor-induced epilepsy – remedy for manic psychosis". Eur. Neurol. 59 (1–2). Switzerland: 105–7. doi:10.1159/000109581. PMID 17934285.
{{cite journal}}: Cite has empty unknown parameter:|month=(help) - ^ Martin D, Valdez J, Boren J, Mayersohn M (2004). "Dermal absorption of camphor, menthol, and methyl salicylate in humans". J Clin Pharmacol. 44 (10): 1151–7. doi:10.1177/0091270004268409. PMID 15342616.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Uc A, Bishop WP, Sanders KD (2000). "Camphor [[hepatotoxicity]]". South Med J. 93 (6): 596–8. PMID 10881777.
{{cite journal}}: URL–wikilink conflict (help); Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ International Programme on Chemical Safety. Poisons Information Monograph: Camphor. http://www.inchem.org/documents/pims/pharm/camphor.htm
External links
- Camphor Evidence-based Monograph from Natural Medicines Comprehensive Database
- INCHEM at IPCS (International Programme on Chemical Safety)