Chemistry of Essential Oils

296 THE CHEMISTEY OF ESSENTIAL OILS

Achillea moschata yields the so-called Iva oil, having the following

characters:—

Specific gravity 0-923 to 0-960

Optical rotation - 12° „ - 15°

Refractive index ........ 1-4761

Acid value 5 to 21

Ester „ 18 „ 44

,, „ (after acetylation) 91 „ 115

It contains cineol, valeric aldehyde, Z-camphor, palmitic acid, and a body

C 24 H 40 O2, termed ivaol by its discoverer Bichenau.

1

Achillea iwbilis also yields an essential oil from the leaves. The oil

has been examined by Echfcermayer,^2 who found it to have a specific

gravity 0*936, optical rotation - 10° 41', and to contain 18*2 per cent, of

esters. It contains borneol, camphene, formic, acetic, and caproic acids

in the form of esters, traces of an unidentified phenol, and a hydrocarbon

of the formula (C 10 H 16 )n.

Achillea ageratum yields an oil of specific gravity 0*856. Its com-

position is unknown.

OIL OF TAGBTBS PATULA.

The flowers of this plant yield about 0*1 per cent, of essential oil

which has been examined by Schimmel & Co.^3 It has the following

characters :—•

Specific gravity

Optical rotation

^Refractive index

Acid value

Ester.

(after acetylation)

0-8856

- 5° 35'

1-49714

2

18-7

74-3

OIL OF ARNICA.
Both the flowers and the root of Arnica montana yield essential oils,
the former to the extent of about *1 per cent., the latter up to 1 per cent.
The plant is indigenous to Europe, growing upon the Swiss and German
mountains, and the more northern plains. It is also met with in Northern
Asia and the south-western parts of America. The oils have the follow-
ing characters:—

Specific gravity

Optical rotation

Refractive index

Acid value.

Ester „.

Flower

. 0-899

• • •

60

22

to

—

—

to

Oil.

0'913

130

33

Root Oil.

0'980 to 1-000

i + 1° to - 2°

1-5070 „ 1-5080

4 „ 10

60 ,, 100

The chemistry of this oil has been investigated by Sigel^4 and the follow-
ing bodies have been identified : phlorol isobutyric ether C8H8(OC4Hg) 2 ,
thymohydroquinone dimethyl ether C 10 H 12 (OCH 3 ) 2 , and phlorol dimethyl
ether C 8 H 8 (OCH 3 ) 2. The flower oil is a blue to bluish-green oil when
fresh, turning yellow or brown on keeping. When expos ed to cold it
becomes solid or semi-solid, owing to the presence of a paraffin hydro-
carbon. Esters of lauric and palmitic acid are also present. Thes3 oils
are only used to a small extent in medicine.

1

Annalen 1 155 (1870), 148.

2

Arch, der Pharm., 243 (1905), 238.

(^3) Bericht, October, 1908, 147. 4 Annalen
1 fl70 (1873), 345.