Chemistry of Essential Oils

MYETACB^E 345

ketone has also been isolated from the oil of Eucalyptus dives
Smith has termed piperitone. This body, of the formula
•C 10 H 18 O, has the following characters:—

Specific gravity 0-9393 at 17°
Boiling-point 224° to 225°
On reduction with sodium it yields an alcohol, C 10 H 18 O, melting at
155° to 156°.
Finally, Eobinson and Smith
J
have separated a phenol from the oil
•of Eucalyptus linearis, which they have named tasmanol.
The phenol was removed from the crude oil in the usual manner by
shaking with aqueous sodium hydrate, washing the aqueous solution
with ether to remove adhering oil, acidifying and extracting with ether.
The residue, which contained a small amount of acetic and butyric acids,
was washed with dilute sodium carbonate, extracted with ether, the
•ether removed and the phenol distilled. It boiled at 268° to 273° C.
(uncor.) and at 175° under 25 mm. pressure. It was optically in-
active, the specific gravity at 23° was 1077, and the refractive index at
:22° was 15269. Besides being soluble in the alkalis the phenol is
soluble in ammonia, partly soluble also in sodium carbonate but not
in bicarbonate. It also dissolves slightly in boiling water. The re-
action with ferric chloride in alcoholic solution is characteristic, the deep
red colour which is first formed remaining persistent for days, after the
alcohol has evaporated. The odour reminds one somewhat of carvacrol
Tinder certain conditions. It contains one methoxy group and appears
ito have two phenolic groups in the para position to each other.
The following are the principal varieties of eucalyptus oil that have
been described:—

OIL OF EUCALYPTUS ACACI^FORMIS.

This tree is the narrow-leaved peppermint gum of New South Wales.

The oil has the following characters :—

Specific gravity 0-8864

Optical rotation + 35-7°

Refractive index 1-4713 at 20°

It contains d-pinene, aromadendrene, and geranyl acetate (?).

OIL OF EUCALYPTUS ACERVULA.

This eucalyptus is a Tasmanian tree, and is also found in South

Australia. The oil has the following characters:—-

Specific gravity ....

Optical rotation ....

Refractive index ....

Saponification value

Eucalyptol

Yield

0-8956

- 1-1°

. 1-4756 at 18°
32-8
21 per cent.
. 0-212
It contains d-pinene, phellandrene, eucalyptol, geraniol, geranyl
acetate, a liquid paraffin hydrocarbon, and a solid (paraffin ?) stearop-
.ten%melting at 55° to 56°.
1
Jour, of Proc. Boy. Soc., N.S.W., 48 (1914), 518.