Two samples consisted of (a) practically pure terpinene ; (b) prac-
tically pure terpinolene.
The presence of terpinolene had hitherto not been observed in nature,
and is remarkable as the oil containing terpinolene showed a very peculiar
behaviour. The crude oil boiled within one degree (Clover does not men-
tion the boiling-point), and had a rotation of + 4°. The reactions for
terpinene and phellandrene were negative, but a bromide of the melting-
point 116° to 117° was obtained in the form of brilliant scales. From
this the presence of terpinolene might be assumed. The oil containing
terpinolene was purified by treatment with potassium hydroxide, distilled
in vacuo, and had then the constants: specific gravity at ^Qo 08361; rota-
tion + 1-7°; 7iD30o 14701; boiling-point 1735
°
to 175° (at ordinary
pressure); 80° to 81° (37 mm. pressure). The rotation decreased con-
siderably between the second and third distillation, although the oil had
been prepared only on the previous day from elemi. In order to accel-
erate a possible change in the principal constituent of the oil, a portion of
it was heated for three hours in a sealed tube on an oil-bath to 200°.
The distillate now showed a rotation of - 75°, and gave a phellandrene
reaction (nitrite, laevo-rotatory, melting-point 119° to 120°). Five days
later an attempt was made to produce terpinolene tetrabromide from the
purified oil, but instead of this there were obtained crystals of the melt-
ing-point 125°, which were dipentene tetrabromide. In the meantime
the rotation of the oil had also changed from + 17° to - 16°; after
a further six days it had increased to - 9*8°; after another month to
34'5°, a proof that a considerable alteration was proceeding spontane-
ously in the oil. After three more weeks the oil was distilled with steam ;
the distillate now had an optical rotation - 38°, and the conversion had
consequently probably come to an end. The tetrabromide produced in
various solvents melted at 125°. Phellandrene could no longer be de-
tected by the nitrite-reaction, probably owing to the presence of a large
quantity of dipentene. In Clover's opinion the almost pure terpinolene
present in the original oil (which had a particularly low boiling-point),
had consequently been converted, by standing for several weeks, into
dipentene, a small quantity of ^-phellandrene, and an unknown laevo-
rotatory terpene.
The high-boiling oil portions had mostly a feeble laevo-rotation, and
their specific gravities fluctuated between 0-900 and 1030; they were
chiefly mixtures of sesquiterpenes and oxygenated bodies. From a frac-
tion with the rotation + 716° a solid substance of the formula C 15 H 26 O
was isolated.
In the case of phellandrene, Clover observed that the a-modification
of this terpene occurs in elemi oil. The rotation of the phellandrene
diminished slowly if left standing at ordinary temperature. When the
phellandrene was left standing, crystals separated on the glass walls of
the bottle, the formation of which must be attributed to autoxidation of
the phellandrene; after purification from hot acetic ether they melted at
164-5° to 1655°, and had a composition corresponding to the formula.
CIOH 18 O 2.
Semmler
l
has detected a small quantity of a sesquiterpene alcohol,
and a phenol ether to which he assigned the name elemicin. This body
has a specific gravity 1 063 at 20°, refractive index 1*5285, and boils at
144° to 147° at 10 mm.
1
Berichte, 41 (1908), 1768, 1918, 2183, 2556.
