The chemistry of essential oils and artificial perfumes / by Ernest J. Parry.

  • Parry, Ernest J. (Ernest John)
Date:
1908
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Licence: In copyright

Credit: The chemistry of essential oils and artificial perfumes / by Ernest J. Parry. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    1 Sesquiterpenes. The sesquiterpenes are polymers of the terpenes, with which they are closely related, of the formula C15H24. A large number no doubt exist, but on account of the difficulty in purifying the hydrocarbons none can be said to be estab- lished as definite individuals until pure derivatives are prepared, whose properties can be studied. The principal well-defined sesquiterpenes appear to be the following: •cadinene, caryophyllene, cedrene, clovene, humulene, ledene, patchoulene, atractylene, santalene and zingiberene, and a hydrocarbon occurring in the oil of Cannabis indica. Cadinene.—This sesquiterpene is found in its laevo-ro- tary form in the oils of cade, patchouli, galbanum and others. Dextro-cadinene is found in the so-called West Indian santal oil. To prepare it in the pure state, Wallach recommends the following process. The fraction of oil of cade boiling be- tween 260° and 280° is saturated with hydrochloric acid gas, ■and the resulting cadinene hydrochloride is purified and re- converted into the hydrocarbon by heating it with aniline. When pure, cadinene boils at 275°, and has a specific gravity •921 at 15-5°, and a refractive index 1-5065. Its laevo-rotation is [a]d = - 98'6°. Dextro-cadinene is found in the oil of Cedrus Atlantica. It forms a dihydrochloride, melting at. 117° to 118°, of the formula C15H242HC1, and corresponding com- pounds with hydrobromic and hydriodic acids. All these com- pounds are laevo-rotary. The dextro-variety yields correspond- ing dextro-rotary compounds. Cadinene yields a well-defined nitrosate when one part of cadinene is cooled in a freezing mixture, and dissolved in three parts of acetic acid. To this is added one part of ethyl nitrite. A mixture of equal parts of concentrated nitric acid and glacial acetic acid is now slowly added, and the whole is