Sources of Camphor
Camphor is a crystalline white substance with a distinctive scent, prized by many for its use in medicinal applications. Its formal name, granted by the International Union of Pure and Applied Chemistry (IUPAC), is 4,7,7-trimethylbicyclo[2.2.1]heptan-3-one. Camphor is found in nature and can also be synthesized. Both natural and synthetic camphor are found in many commercial products.
Camphor is derived from the wood of the Cinnamonum camphora tree. This tree is found mainly in Asia, but may be cultivated in India, Egypt, Madagascar, southern Europe, Argentina, California and Florida. In one process, the oil from the tree is collected and heated by steam, causing the oil to become volatile. Then the volatile oil is cooled, and the liquid pressed out, leaving the crude camphor behind. The crude camphor is then purified at refineries. One method of purification involves mixing the camphor with lime and sand, and then subliming it, causing it to immediately go from solid a phase into gas phase without passing through a liquid phase. The camphor is then condensed upon a cooled surface and cut into solid slabs for export.
A second form of purification involves condensing the camphor into the form of small crystals.
Regardless of collection and purification method, extraction of natural camphor results in a product that is completely dextrorotatory, meaning that it rotates polarized light toward the right.
Camphor is commonly synthesized from pinene, which is the primary component of oil of turpentine, through the alcohol intermediate borneol. Synthetic camphor may contain trace amounts of borneol, and may thus be somewhat impure, since the final synthesis reaction may not reach completion, and it is difficult to completely separate borneol from camphor. The camphor resulting from this process is an equal mixture of dextrorotatory and levorotatory. This means half of it rotates polarized light toward the right, half of it rotates polarized light toward the left, and the net effect is that the chemical is optically inactive.
Commercial Products Containing Camphor
Camphor is found in a wide variety of commercial products, including insecticides, soaps and disinfectants, deodorants, perfumes, and air fresheners. In these products, with the exception of insecticides, it is used to provide a pleasant odor.
Medicinal Uses of Camphor
Some over-the-counter medicines take advantage of the mild anesthetic benefits of camphor. In formulations for external use, at low concentrations, camphor is considered safe; however when ingested, camphor may cause neuromuscular symptoms, such as seizures and confusion.