Chemistry of Essential Oils

COMPOSITE 303

The known constituents of the oil are the terpene, limonene, terpineol,

and traces of citronellal.

OIL OF ELECAMPANE.

This oil is distilled from the roots of Inula helenium, a plant indi-

genous to Southern Asia and Siberia, and found to a fair extent in

Southern Europe and North America. The oil has the following

characters :—

Specific gravity 1-013 to 1-0380

Optical rotation + 120 to + 123° 45'

Refractive index ....... 1 * 5220

Acid value 6 to 8

Ester ,„ 160 „ 180

„ „ (after acetylation) .... 186 „ 199

The oil is semi-solid, owing to the deposition of crystals of alantolactone,

the above specific gravities being those taken in the superfused condi-

tion. The principal constituent of the oil is alantolactone, with small

quantities of alantic acid, alantol, and helenin (which is probably identical

OH

/

with isoalantolactone). Alantie acid has the formula CUH 20 , and

COOH

alantol is isomeric with camphor C 10 H 16 O.

OIL OF CHRYSANTHEMUM JAPONICUM.

The leaves and flowers of this plant yield an essential oil which is

known in Japan as kiku oil. It has a specific gravity about 0*885 and

boils at 165° to 175°. According to Perrier,

1

the green leaves of the

plant yield an oil of specific gravity 0*932 and refractive index 1*4931.

It contains a paraffin hydrocarbon, and probably angelic acid in the

form of esters.

OIL OP CHRYSANTHEMUM CINBRARI^EFOLIUM.

The flowers of this plant, growing largely in Dalmatia and Monten-

egro, and which, when ground, form the insect powder of commerce,

yield about 0 07 per cent, of essential oil. According to Siedler,^2 it con-

tains a paraffin C 1 4H3 0 melting at 54° to 56° and a substance melting at

62°, probably palmitic acid. It also contains a phenol, and probably

butyric acid.

OIL OP CHRYSANTHEMUM MARGINATUM.

Shinosaki^3 has obtained 0*005 per cent, of a greenish blue essential
oil by distilling this plant. The oil has the following characters :—

Specific gravity 0*923 at 15°

Optical rotation - 46'58°

Refractive index 1*5020 at 20°

Saponification value 16*3

„ „ (after acetylation) .... 63-1

(^1) Butt. Soc. Chim., iii. 23 (1900), 216.

• Ber. d. deutsch. Pharm. Ges., 25 (1915), 297.
  *J. Chem. Ind. Tokyo (1919), 22, 455.