Camphor

Camphor (ˈkæmfər) is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel (Cinnamomum camphora), a large evergreen tree found in East Asia; and in the kapur tree (Dryobalanops sp.), a tall timber tree from South East Asia. It also occurs in some other related trees in the laurel family, notably Ocotea usambarensis. Rosemary leaves (Rosmarinus officinalis) contain 0.05 to 0.5% camphor, while camphorweed (Heterotheca) contains some 5%. A major source of camphor in Asia is camphor basil (the parent of African blue basil). Camphor can also be synthetically produced from oil of turpentine. The compound is chiral, existing in two possible enantiomers as shown in the structural diagrams. The structure on the left is the naturally occurring (+)-camphor ((1R,4R)-bornan-2-one), while its mirror image shown on the right is the (−)-camphor ((1S,4S)-bornan-2-one). Camphor has few uses but is of historic significance as a compound that is readily purified from natural sources. The word camphor derived in the 14th century from Old camphre, itself from Medieval camfora, from kāfūr, perhaps through karpūra, apparently from Austronesian kapur 'lime' (chalk). In Old Malay, camphor was called kapur barus, meaning "the chalk of Barus", referring to Barus, an ancient port near modern Sibolga on the western coast of Sumatra. This port traded in camphor extracted from the Borneo camphor trees (Dryobalanops aromatica) that were abundant in the region. Camphor has been produced as a forest product for centuries, condensed from the vapor given off by the roasting of wood chips cut from the relevant trees, and later by passing steam through the pulverized wood and condensing the vapors. By the early 19th century most camphor tree reserves had been depleted with the remaining large stands in Japan and Taiwan, with Taiwanese production greatly exceeding Japanese. Camphor was one of the primary resources extracted by Taiwan's colonial powers as well as one of the most lucrative.