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

  • Parry, Ernest J. (Ernest John)
Date:
1908
Catalogue details

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)

    32/594 (page 20)
    according to Wallach (Ann. Chem., ccxxxix., p. 24), by diluting with an equal volume of ether the fraction of Swedish turpen- tine which boils between 174° and 178°. This is saturated with dry hydrochloric acid gas, and, after allowing the whole to stand for two days, the ether is distilled off, and the residue crystallised. By recrystallisation from warm alcohol it can be obtained pure, when it melts at 72°. The hydrocarbon is obtained from its dihydrochloride by heating with aniline, or with acetic acid and sodium acetate. Sylvestrene has an odour recalling that of bergamot. It boils at 176° to 177°, has a specific gravity 851 at 155°, and a refractive index 1*4747. Natural sylvestrene is dextro-rotary [a] d = + 66'3°. A characteristic colour reaction of this terpene is as follows : one drop of sylvestrene is dissolved in a little acetic anhydride, and one drop of concentrated sulphuric acid is added. An intense blue colour results. It is a most stable terpene, which polymerises under the influence of heat, without yielding any of the isomeric terpenes. It forms a characteristic dihydrochloride, already mentioned, and a tetrabromide C10H16Br4, melting at 135°. The nitro- sochloride melts at 106° to 107°. The various compounds of sylvestrene which have been prepared are, as is the hydrocarbon, dextro-rotary. Carvestrene.—This hydrocarbon is, in all probability, the optically inactive variety of sylvestrene. But this cannot be definitely proved until it is resolved into the two optically active varieties, or until laevo-sylvestrene is discovered, when a mixture of the two sylvestrenes should yield carvestrene. It yields the characteristic sylvestrene colour reaction men- tioned above, which the other terpenes do not. Carvestrene has not been found in nature, having been prepared by Baeyer (Berichte, xxvii., p. 3485) by the distillation of carylamine hydrochloride, C10H17NH2. HC1, in an atmosphere of dry hydrochloric acid gas. It is an optically inactive