Chemistry of Essential Oils

452 THE CHEMISTRY OF ESSENTIAL OILS

melting at 180° to 184° free palmitic acid was detected. Geraniol was
found in the oil, but in small quantity only.
Asahina and Konno
l
have also examined the oil recently, and state
that they find 13 per cent, of citronellal present. The oil which they
examined had the following characters :—
Specific gravity 0-8511 at 19°
,, rotation + 45'45°
They also identified d-/?-phellandrene and cumic aldehyde.
There has recently been imported into this country a " Japanese
pepper " which Holmes has identified as the fruit of Xanthoxylum alatum,
Its essential oil has been examined by Umney
2
and found to have a
specific gravity 0*889, and an optical rotation - 23°. It contains a crystal-
line stearoptene melting at 80°.
Shinosaki
3
has examined the essential oils distilled from the leaves of
Xanthoxylum ailanthoides, and found them to have the following char-
acters :—

Specific gravity.

Optical rotation.

Refractive index.

Acid value.

Saponification value.

Full-grown

Leaves.

. 0-8437
. - 6° 35'
1-4474
0-94
2-81

Half-grown

Leaves.

0-8385

• 5° 75'
  1-4408

4-21

Young

Leaves.

0-8390

• 6° 63'
  1-4440
  0-04
  1-83
  The principal constituent of the oil is methyl-nonyl-ketone, terpenes, and
  about 1-5 per cent, of phenols.
  The essential oil of the Formosan plant known as Yamakosho may
  be mentioned here, its botanical origin being unknown, but the oil having
  been reported on also by Shinosaki.
  4
  From the leaves he obtained 12
  of a brownish-yellow essential oil having an odour of camphor. It had
  the following characters :—
  Specific gravity 0-9049
  Optical rotation - 18-8°
  Refractive index 1-4635
  Ester value after acetylation....... 48 66
  It contains eucalyptol and hydrocarbons.
  The oil from the fruits of Xanthoxylum acanthopodium known as
  " Wartara seeds " has been examined by Schimmel & Co.^5 The oil had
  the following characters :—
  Specific gravity 0-8714
  Optical rotation + 6° 31'
  Saponification value 271
  On distillation in vacuo (14 mm.) the oil gave the following fractions :—

Fraction. Boiling-point.

Specific Gravity

at 22°. o at 18-5°.

65° to 70C

70° „ 80°

80° „ 90°

90°

90° to 100°

100° „ 130°

-841

0-846

0-856

0-865

0-865

0-939

+ 0° 26'

+ 4° 17'

+ 11° 38'

+ 13° 43'

+ 12° 39'

• 6° 2'

Quantity of

Distillate.

45 c.c,

9 ,.

34 „

19 „

27 „

(^1) ApotJieker Zeit., 32 (1917), 556.
(^3) Jour. Soc. Chem. Ind., 34 (1915), 1270.
(^4) Jour. Chem. Ind. Tokyo, 18 (1915), 1081.
(^2) .. and E.O.R. (1912), 37.
(^5) Report, April, 1900, 49.