Chemistry of Essential Oils

294: THE CHEMISTKY OF ESSENTIAL OILS

OIL OF TANSY.

This oil is distilled from the herb Tanacetum vulgare, a native of

England, but cultivated in France, Germany, the United States, etc.

The yield of oil from the fresh herb is about *1 to *2 per cent., and

from the dried herb about twice this quantity. The oil has the following

characters:—

Specific gravity 0

• 925 to 0'940
  Optical rotation + 24° „ + 35°
  Refractive index 1-4570 „ 1-4600
  Acid value 0 „ 1
  Ester „ 5 „ 16
  „ „ (after acetylation) 24 „ 35
  English distilled oil is, however, laevo-rotatory, from - 25° - 35°, and
  occasionally foreign oils vary outside the above limits, the optical rota-
  tion being as low as — 3
  ~
  , and the refractive index rising to 1

4750. It is soluble in 4 volumes of 70 per cent, alcohol. The earliest thorough
      examination of this oil was made by Bruylants * who stated that it con-
      tained an aldehyde C 10 H 16 O, which he called tanacetylhydrine. Semmler
      examined this body and showed that it was a ketone, and renamed it
      tanacetone. Wallach has shown, however, that it is identical with that
      ketone of thuja oil which he had already named thujone. Schimmel
      & Co. showed that the oil contains traces of borneol and some laevo-
      camphor, a fact previously indicated by Persoz.
      2
      The English oil, which
      is strongly laevo-rotatory, also contains much more camphor than the
      ordinary American oil.

OIL OP TANACETUM BALSAMITA.

Tanacetum balsamita yields about *07 per cent, of essential oil. Th&

oil has the following characters:—

Specific gravity 0-940 to 0-950

Optical rotation - 40° „ - 54°

Ester value 19 „ 25

On standing in a cold place crystals of a paraffin-like substance were

deposited. The oil is not soluble in twice its volume of 80 per cent,

alcohol, but is in the same quantity of 90 per cent, alcohol. The oil

distilled completely between 207° and 283°, and gave the following

fractions:—

207' to 220° = 10-4 per cent. 240° to 250° = 12'4 per cent.

220° „ 230° = 16-8 „ 250° „ 283° = 28'2 „

230° „ 240° = 18 „ Besidue = 21'2 „

OIL OF TANACETUM BOREALE.

Tanacetum boreale yields about 0*12 per cent, of essential oil. It

has the following characters :—

Specific gravity 0'960

Refractive index 1-4920

Acid value- 30

Ester „ 40

It is soluble in 2 volumes of 80 per cent, alcohol.

J

Berichte, 11 (1878), 449.

2

Oomptes rendus, 13 (1841), 436,