Chemistry of Essential Oils

(Tuis.) #1

ZINGIBEBACE^E 105


-danielli. The yield of oil was 233 per cent., its specific gravity was
-907 and its optical rotation - 20° 34'. The oil is soluble in 7 to 8
parts of 80 per cent, alcohol. It contains cineol and possesses an odour
which prevents its being employed as a substitute for the ordinary oil.
Bengal cardamom oil is obtained from Amomum aromaticum, which
yields about 1 to T2 per cent, of oil having a specific gravity 0-920 and
optical rotation - 13°. This oil contains a large quantity of cineol.
The seeds of Amomum Melegueta, one of the Zingiberacese indigenous
to tropical West Africa, yield the so-called "grains of paradise" oil.
which is obtained to the extent of 0
3 to 0'75 per cent. The oil has
a. specific gravity about 0'894 and optical rotation about - 4°. It is
not clearly soluble in 90 per cent, alcohol. Schimmel & Co.
1
have dis-
tilled a sample, which was found to have the following characters:—
Specific gravity 0897
Optical rotation - 3° 10'
Refractive index 1-49116
Its ester value was 41
2, and ester value after acetylation 63'9.
Schimmel & Co.^2 have examined the oil obtained from cardamom
roots from Indo-China. They obtained 0'64 per cent, of oil having the
following characters : ^ir,o 0'9066; ao - 32° 57'; ^020° 1'48151; acid value
3'7; ester value 87'9; ester value after acetylation 96'7. The oil was
soluble in 0'5 volumes of 95 per cent, alcohol; when more alcohol was
added the mixture rapidly turned turbid, and did not .become clear
again until the solvent had been increased to 4 volumes. Fractional dis-
tillation under diminished pressure (5 mm.) gave the following result:—



  1. to

  2. 35° „

  3. 40° ,,

  4. 100° ,

  5. 110° „

  6. 115° „

  7. residue


35°


40°


100°


110°


115°


145°


5-4 per cent.
8-7
5-4
10-6
44-2
6-4
19-3 „

«D -


«D -


«D -


«D -


«D -


aD -
«D -



17°


31°


45°


33 °


39°


10'


32'


5'


10'


°
14'
15'
Fractions 1 and 2 contained cineol, which was identified from the
•double compound it gave with resorcinol. From fractions 4 and 5 a
portion boiling between 117° and 120° (5 mm.) was separated by re-
peated fractionation. Saturated with hydrochloric acid gas in dry
ethereal solution at - 18°, this fraction yielded a hydrogen chloride
•compound which, when recrystallised from methyl alcohol, had melting-
point 79° to 80°. The hydrochloride was inactive; the chlorine-deter-
mination gave the following result:—
0-4306 subst. : 05928 g. AgCl
Cl Found Calc. for C 15 H 24 , 3HC1.
34
06 per cent. 33'9 per cent.
The probability of this body being bisabolene hydrochloride was
•confirmed by further examination. With sodium acetate and glacial
acetic acid a sesquiterpene was eliminated from it which, when twice
fractionated, was found to possess the following constants : 265° to 267°
(757 mm.); d^ 0-8748 ; aD ± 0°; nm& 1-49063. With hydrochloric acid
this hydrocarbon yielded again the trihydrochloride melting between
79° and 80°.
The residue of distillation of cardamom-root oil solidified at about


(^1) Re1)ort
J October, 1914, 32. 2I6id., 1911, 105.

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