What is Camphor?
Camphor, an organic compound (organic camphor) with a penetrating, mildly musty fragrance, has been used as a part of incense and as a medicinal for decades. Modern uses of the camphor compound have been as a plasticizer for cellulose nitrate and also as an insect repellent, specifically for moths. The molecular formula of camphor is given as C10H16O.
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About Camphor
Camphor takes place in Cinnamomum camphora, camphor laurel, which is common in China, Japan, and Taiwan. It can be isolated by passing steam via pulverized wood and condensing the vapours; camphor compound crystallizes from the distillate's oily portion, and it is purified by sublimation and pressing. Several methods have been used to produce camphor compounds from the -pinene compound since the early 1930s.
Camphor belongs to the organic compound group, which is defined as terpenoid ketones. The reactions and the structure peculiar to it were fundamental problems of 19-century organic chemistry. This pure camphor compound is a white colour and waxy solid that melts at around 178°–179° C.
Production
For centuries, camphor has been generated as a forest product by condensing vapour produced by roasting wood chips, which are cut from the related trees, and then, bypassing the steam through pulverised wood and vapour condensation. Many common camphor tree stocks had been exhausted by the early nineteenth century, including the remaining large stands in Taiwan and Japan, with Taiwanese production far exceeding Japanese. Camphor compound was the primary resource that was extracted by the colonial powers of Taiwan and one of the most lucrative as well.
First, the Chinese and then, the Japanese have established monopolies on the Taiwanese camphor. In 1868, a British naval force sailed into one of the local British representatives, and the Anping harbour demanded the end of the monopoly of the Chinese camphor, which is after the local Qing representative had refused, the British bombarded the town and took that harbour. Then, the "camphor regulations" team negotiated between the two sides and subsequently saw a brief end to the monopoly of the camphor.
Physical Use of Camphor
The sublimating capability of the camphor gives it many uses, where some of the use of camphor is given below.
Plastics
The first significant man-made plastics were the low-nitrogen (otherwise "soluble") nitrocellulose (or pyroxylin) plastics. Camphor compounds were used in significant amounts (130) as the plasticizer in nitrocellulose lacquers, as well as other lacquers and plastics, in the early decades of the plastics industry.
Pest Deterrent and Preservative
Camphor compound is believed to be toxic to insects and is therefore used as a repellent sometimes. Camphor can be used as an alternative to the mothballs. Camphor compound's crystals are at times used to prevent damage to insect collections by other tiny insects. It is kept in the clothes, which are used in festivals and special occasions, and also as a cockroach repellent in the cupboard corners. The camphor incense sticks or smoke of camphor crystal can be used as an environmentally-friendly mosquito repellent.
Some recent studies have revealed that the essential oil of camphor can be used as an effective fumigant against the red fire ants because it affects the climbing, attacking, and feeding behaviour of both minor and major workers.
Camphor can also be used as an antimicrobial substance. Camphor oil was also one of the main ingredients in the embalming, which the ancient Egyptians used for mummification.
Solid camphor compound releases the fumes that produce a rust-preventative coating and is thus stored in the tool chests to protect tools against rust.
Perfume
In the ancient Arab world, camphor compound was a commonly used perfume ingredient, as per the Perfume Handbook. The Chinese people referred to the best camphor compound as "brain perfume of dragon" because of its "portentous and pungent aroma" and "centuries of uncertainty over its mode of origin and provenance."
Medicinal Uses
Camphor compound is regularly applied as a topical medication as an ointment or skin cream to relieve the itching problems from insect bites, joint pain, or minor skin irritation. It can also be absorbed in the skin epidermis, where it stimulates the nerve endings sensitive to cold and heat, producing a cool sensation when applied gently or warm sensation when applied vigorously. The action on nerve endings induces slight local analgesia.
Camphor compound can also be used as an aerosol, typically by steam inhalation, to inhibit coughing and relieving the upper airway congestion because of the common cold.
In higher doses, camphor compounds produce symptoms of disorientation, irritability, muscle spasms, lethargy, abdominal cramps, vomiting, and convulsions. In adults, lethal doses are in the range of 50–500 mg/kg (orally). In general, two grams of camphor cause serious toxicity, whereas four grams are potentially lethal.
Camphor compounds have limited use in veterinary medicine, such as a respiratory stimulant for horses.
Camphor compound was used by Ladislas J. Meduna to induce seizures in schizophrenic patients.
Traditional Medicine
Camphor compound has been used in traditional medicine over centuries, probably as most generally as a decongestant. Camphor was also used in ancient Sumatra to treat swellings, inflammation, and sprains. Camphor was also used for centuries for various purposes in traditional Chinese medicine.
It can also be used in India since ancient times.
Pharmacology
Camphor compound is a parasympatholytic agent which acts as a non-competitive nicotinic antagonist at nAChRs.
FAQs on Camphor
1. What is camphor and what is its chemical formula?
Camphor is a waxy, flammable, and transparent solid known for its strong, penetrating aromatic odour. Chemically, it is classified as a bicyclic monoterpene ketone. The chemical formula for camphor is C₁₀H₁₆O. It is found naturally in the wood of the camphor laurel tree but can also be synthesised chemically from turpentine oil.
2. What are the key physical properties of camphor?
Camphor exhibits several distinct physical properties that are important for its identification and application. Key properties include:
- Appearance: It is a waxy, crystalline solid that is typically white or transparent.
- Odour: It has a very strong, characteristic, and pungent aroma.
- Sublimation: Camphor has the unique property of sublimation, meaning it transitions directly from a solid to a gas at room temperature without becoming a liquid.
- Solubility: It is poorly soluble in water but readily dissolves in organic solvents like alcohol, ether, and chloroform.
- Flammability: It is a highly flammable substance.
3. What are the primary uses and applications of camphor?
Camphor is used in a variety of applications, ranging from medicinal to industrial. Some of its primary uses include:
- Medicinal Products: It is a common ingredient in topical balms, liniments, and creams used to relieve pain, irritation, and itching from insect bites or skin conditions.
- Insect Repellent: The strong odour of camphor makes it an effective moth and insect repellent.
- Religious Ceremonies: In many cultures, particularly in Hinduism, camphor is burned as part of religious rituals and aarti.
- Industrial Use: It is used as a plasticiser for nitrocellulose, a component in early plastics and smokeless gunpowder.
- Perfumery: A small amount is sometimes used in fragrances for its unique scent profile.
4. What does the chemical structure of camphor look like?
The chemical structure of camphor is a bridged bicyclic system. It is based on a bornane framework with a ketone group on the second carbon atom. This structure is rigid and contains two fused rings, giving it a distinct three-dimensional shape. This complex, strained structure is responsible for many of its unique chemical and physical properties.
5. Why does a piece of camphor appear to 'dance' or move on the surface of water?
The movement of camphor on water is a classic example of a phenomenon related to surface tension. Camphor slowly dissolves in water, spreading out as a thin film on the surface. This film reduces the water's surface tension in the area around it. If the camphor piece is irregularly shaped, it dissolves unevenly, creating a gradient where surface tension is lower on one side than the other. The water with higher surface tension pulls on the camphor piece with greater force, causing it to move. This continuous, erratic motion is known as the Marangoni effect.
6. Is camphor safe for direct consumption or for use on the skin?
Camphor is not safe for consumption. Ingesting camphor can be highly toxic and may lead to seizures, confusion, and damage to the liver and nervous system. For skin application, it is generally considered safe only when used in low concentrations as part of approved topical products like creams and balms. Applying pure camphor or products with high concentrations directly to the skin can cause irritation, redness, and burning. It should never be applied to broken or injured skin.
7. How is camphor's property of sublimation explained at a molecular level?
Sublimation occurs when a substance transitions directly from a solid to a gas. In camphor, this happens because the intermolecular forces (specifically van der Waals forces) holding the camphor molecules together in their crystal lattice are relatively weak. At room temperature, the molecules have enough thermal energy to overcome these weak forces and escape directly into the gaseous phase, bypassing the liquid state entirely. Its symmetrical, non-polar structure contributes to these weaker intermolecular attractions compared to other solids of similar molecular weight.
8. What is the difference between natural and synthetic camphor?
The main differences between natural and synthetic camphor lie in their origin and optical activity. Natural camphor is extracted from the wood of the camphor laurel tree (*Cinnamomum camphora*) and is typically the dextrorotatory or (+)-isomer. Synthetic camphor is produced commercially from alpha-pinene, a component of turpentine oil. The synthetic version is a racemic mixture, meaning it contains an equal amount of the dextrorotatory (+) and levorotatory (-) isomers. While they are chemically identical (C₁₀H₁₆O), this difference in optical isomers can affect their biological and pharmaceutical properties.
