70 THE CHEMISTKY OF ESSENTIAL OILS
Schimmel & Co. have examined seven samples with especial re-
ferences to their geraniol and citronellal values, and give the following
results:—
Specific
Gravity.0-8913
0-8859
0-8866
0-8868
0-8883
0-8925
0-8881
Rotation.- 2° 15'
- 1° 45'
- 1° 35'
- 1° 22'
- 1° 28'
- 2° 11'
- 1° 11'
Total
Acetylisable
Constituents.85*4 per cent.
87-6
88-7
88*0
87-5
84-7 „
91-0Geraniol.35-3 per cent.
35-3
36-4
33-5 „
40-1 ,,
35-9
37-0 ,,Citronellal.Kleber's
Method.36-0 per cent.
40-0
40-0
38-8
38-7
38-0
36-8Dupont's
Method.36-6 per cent.
45-2 „
46-3 „
39-5
35-4 „
37-2
40-1 „Abnormal samples are occasionally met with, which are slightly
dextro-rotatory, or whose specific gravity may rise to 0900 to 0905.
In the determination of acetylisable constituents in Java citronella
oil it is necessary to use considerable excess of acetic anhydride.
Durrans l prefers the following quantities and conditions :—
Ten c.c. of the oil with 20 c.c. acetic anhydride (95 to 100 per
cent.) and 3 grms. anhydrous sodium acetate are boiled for two hours
utxder a reflux condenser. The mixture is then cooled, about 50 c.c.
of water added through the condenser, the flask heated on the steam-
bath for fifteen minutes and then cooled, the condenser being connected
to the flask during the whole of these operations. The contents of the
flask are washed in a separatory funnel with cold water (or brine), then
with a 1 per cent. Na 2 CO 3 solution until neutral, and finally with water.
The washed oil is dried with anhydrous sodium sulphate, and from 25
to 5 grms. saponified with 50 c.c. normal alcoholic KOH for two hours
under a reflux condenser, the excess being titrated back with acid and
phenolphthalein as usual.
Java citronella oil owes its odour principally to citronellal with
geraniol and some citronellal. Traces of methyl-eugenol, about 1 per
cent, (as against 7 or 8 per cent, in Ceylon oil), are present, and about 02
per cent, of citral. A sesquiterpene, isolated by Semmler and Spornitz,^2
and termed by them sesquicitronellene, is also present. This body has
the following characters:—
Specific gravity at 20° 08489
Optical rotation + 0° 36'
Refractive index 1-5325
Boiling-point at 9 mm 138° to 140°
Spornitz^3 also detected an oxide in the higher boiling fractions of
the oil, which he named dicitronelloxide, a colourless liquid of the
formula C 20 H 34 0, and having a specific gravity 09199 at 20°, and optical
rotation - 4°.
Furukawa^4 finds eugenol and probably chavicol, and traces of citronellic
acid in Java citronella oil.
There are a few varieties of citronella oil, distilled in various coun-
1
P. and E.O.R. (1911), 201 ; (1912), 123.
a
Bericht, 46 (1913), 4025.
(^3) Ibid., 47 (1914), 2478. 4 Jour. Chem. Ind. Tokyo (1918), 21, 515.