Camphor-Synonyms Gum camphor; Japan camphor; Formosa camphor. Laurel camphor

2.1.1 Camphor

Synonyms Gum camphor; Japan camphor; Formosa camphor. Laurel camphor.

Biological Source It occurs in all parts of the camphor tree, Cinnamonum camphora. T. Nees & Ebermeier, belonging to family Lauraceae.

Geographical Source The word camphora is derived from the Arabic Kafur, meaning chalk. The camphor tree, which is a huge evergreen plant, is found to be indigenous to Japan, China and Taiwan. It has also been naturalized specifically in the Mediterranean region eg; Algeria, Tunsia, Libya, Egypt, Italy and Greece. Besides it is grown in South Africa, Ceylon, Brazil, Jamaica, Florida and California. History reveals that Borneo camphor (from Borneol) arrived in Arabia in the sixth century and in Europe in the twelth century. Earlier, the worlds 80% supply of natural camphor was provided by Taiwan (Formosa) alone and the rest 20% by Japan and Southern China. Soonafter the second World War (1945) the commercial production of synthetic camphor has more or less catered for the ever increasing demand of camphor in the world market.

Preparation It is prepared from the chipped wood by subjecting it to steam distillation and subsequently collecting the distillate in specifically designed chambers where camphor will solidify on its miner walls upon colling and may be collected later on from the bottom of the chamber. The crude solidified camphor is purified by mixing it with a suitable proportion of soda lime, sand and charcoal; and subjecting the mass to sublimation at controlled temperature when pure crystals of camphor would be collected as a sublimate. It is finally compressed into either small cubes or thin plates, wrapped and exported.

Camphor from Volatile Oils It may be prepared from volatile oils by two simple methods, namely:

Methods-I In case, the oil contains a substantially large proportion of camphor, it may be separated

by deep freezing or sudden chilling; and if the camphor content in oil is not so much it is mostly fractionated and the camphor containing fraction is chilled to recover camphor.

Method-II Camphor may be recovered from volatile oils by the instant production of insoluble complexes with strong mineral acids eg; sulphuric acid 80% (30N).

Synthetic Camphor (or Borneol Camphor) The camphor is obtained commercially from α-pinene present in the turpentine oil through several steps sequentially e.g., treatment with HCl, isomerization, treatment with KOH and finally oxidation with HNO₃ as given below:

Description

Colour : Translucent mass with crystalline fraction

Odour : Characteristic odour

Optical Activity : Natural camphor = Dextro rotatory (+ 41^o to 43^o) Synthetic camphor = Racemic mixture;

Solubility : Soluble in water (1:600)

Chemical Structure Camphor is a bycyclic terpenoid ketone as given below:

In the presence of platinum black it undergoes hydrogen at ambient temperature giving rise to isoborneol as the major product and traces of borneol.

Its prolonged hydrogenation often yields camphene.