Chemistry of Essential Oils

UMBELLIFEK^E 307

French ,

Italian ,

Morocco ,

Russian.

.

• 4 per cent.


• -5
  . •2 to -3 per cent.


• -8 „ -1 „

Dutch.

Moravian

East Indian

Thuringian

the world. The average yield from various fruits is given by Schimmel
& Co. as follows :—
•6 per cent.
'8 „
•15 to -2 per cent.
•6 „ -8 „
Thuringia and Eussia have, of late, been the most important pro-
ducers, the crops from these districts sometimes reaching as high a
figure as 450 tons. The oil has an intense odour of the seeds, which is
much impaired if immature fruits have been used in the distillation.
This is explained by the following experiment undertaken by Schimmel
& Co. A portion of a crop was gathered in the early summer, whilst
the herb was in early flower, and the whole herb distilled. Five weeks
later, when half ripe and just starting to seed, another portion was
gathered and distilled. In another month, the fully ripe fruit of a
third portion was distilled. The result of the examination of the oils
obtained is given below in Schimmel & Co.'s own language:—
" 1. Oil from the entire Flowering Plant in the Green State.—Yield
012 per cent. Specific gravity 0853. Insoluble in 70 per cent, alcohol.
Extremely objectionable, bug-like odour. After 2£ months the specific
gravity of the oil had increased to 0*856. The optical rotation (which
had not been determined immediately after distillation) was then

• 1° 2' in a 100 mm. tube at 18° C. The bug-odour had disappeared
  almost entirely. It would therefore seem that in the meantime the
  carrier of the odoriferous principle had become polymerised or other-
  wise transformed.
  " 2. Oil from Green Half-ripe Coriander Herb, with Fruit.—Yield
  0-17 per cent. Specific gravity 0866. Optical rotation + 7° 10' at 18°.
  Soluble in three parts of 70 per cent, alcohol. Odour resembling that
  of coriander, with a subsidiary odour reminding of bugs. After one
  month the specific gravity had increased to 0869.
  " 3. Oil from Ripe Coriander Fruit, distilled immediately after har-
  vesting.—Yield 0 83 per cent. Specific gravity 0876. Optical rotation
  -h 10° 48' at 16°. Soluble in three parts of 70 per cent, alcohol. Pure
  coriander odour."
  Pure coriander oil has the following characters :—
  Specific gravity 0870 to 0-885
  Optical rotation + 7
  °
  „ + 14°
  Refractive index 1-4635 „ 14760
  Acid value ......... 1 „ 5
  Ester „ 3 „ 22

The oil is soluble in 3 volumes of 70 per cent, alcohol.
On fractional distillation from 45 to 55 per cent, is obtained between
190° and 200°, indicating a due proportion of coriandrol.
The oil is sometimes adulterated with orange oil, which causes a
lowering of the specific gravity and a considerable rise in the optical
rotation, It also interferes with the solubility in 70 per cent, alcohol.
Cedar-wood oil and turpentine have also been met with as adulterants.
Semmler^1 isolated the characteristic component of this oil, which
he termed coriandrol, an alcohol of the formula C 10 H 17 OH. Barbier
2
has, however, shown that this is identical with dextro-lm&lol. The
only other known constituent of the oil is pinene.

*

Berichte, 24(1891), 206.

3

Comptes rendus, (^116) , 1459.