110 THE CHBMISTKY OF ESSENTIAL OILS
4.
Yield, 14'0 per cent. oil.
Specific gravity (15°), 0-9233 ; optical rotation - 37'60°.
Fractionation of 50 grms. :
Below 220°.
220° to 230°
230° „ 240°
240° „ 250°
•250° „ 260°
260° „ 270°
270° „ 280°
ResidueO'O grms. =
2-3 „ =
1-5 ,, =
2-6 „ =
20-3 „ =
15-5 „ =
3-7 „ =
4'1 „ =00
4-6
3-0
5-2
40-6
31-0
7'4
8-2
per cent.^„ J
" 1
" 1„ J
Below 250°.250° to 280°.Residue.12'8 per cent.. 79-0 „
8-2 „
50-0 100-0 100-0
The chemistry of this oil is in need of further elucidation, as it is
<ilear that there are several constituents present which have, so far,
escaped identification. The terpene dipentene is present, and probably
small quantities of pinene or camphene; cadinene is present, as well as
a second sesquiterpene not yet identified. There is also present, es-
pecially in the oil distilled from old fruit, which has doubtless become
partially oxidised, a small amount of the so-called cubeb-camphor.
This body, C15H25OH, appears to be a crystalline sesquiterpene alcohol
derived from the sesquiterpenes (or one of them) by oxidation. From
a mixture of ether and alcohol it crystallises in rhombs, melting at 65°
1
and is laevo-rotatory. It boils at 248°, with decomposition. The nature
of the blue oil found in the higher fractions is unknown.
Umney and Potter^2 have reported on some " false cubebs," the fruit
of an unknown species of pepper. These false cubebs may, and ap-
parently do, find their way into commerce, and if distilled with genuine
•cubebs produce a quite abnormal oil. The oil from these false cubebs
has a specific gravity about 0-894 and an optical rotation + 16°. The
following results were obtained on fractional distillation, and are com-
pared with those of a genuine oil under identical conditions :—FRACTIONATION.False Cubeb Oil.1
Below 160°.. 12 per cent.
160° to 170°
170° 1
180° 1
190° 2
200° 2
230° 2
240° 2
250° 2
260° 2, 180°
, 190°
, 200°
, 230°
, 240°
, 250°
, 260°
, 270°
8
20
6 4 8 2 4 6
10
Pure Cubeb Oil.Below 200°.
200° to 230°
230° „ 240°
240° „ 250°
250° „ 255°
255° „ 257°_
—
—
5 per cent. only.
11
3
15
31
25The t'ractionation figures, gravity, and optical rotation indicate that
this oil has an entirely different composition from that of normal cubeb
oil. The oil has been further investigated as regards its ester and
alcohol values which are :—
1
Schmidt, Arch, der Pharm., 191 (1870
- , 23 ; Schaer and Wyss, Arch, der Pharm.,
206 (1875), 316, give 67°; and Winckler, Annalen, 8 (1833), 203, gives 70°.
2P. and E.O.B. (1912), 64.