Chemistry of Essential Oils

N. O. GRAMINEJE 85

count of the crude methods of distillation used by the natives, wherein
too little water is used in the stills, with the result that the grass is
burned), but sometimes water-white when rectified. It has a char-
acteristic geranium odour, and is a most popular perfume where an
odour recalling roses and geranium is required at a comparatively low price.
The pure oil has the following characters:—
Specific gravity 0-886 to 0-899
Refractive index 1-4720 „ 1-4780
Optical rotation -3° „ +5°
Acid value.. 0 „ 3
Ester „ 12 „ 50
Total geraniol 78 to 94 per cent.
The oil is soluble in 3 volumes of 70 per cent, alcohol.
Samples distilled in Java have been examined by Schimmel & Co.^1
and found to have the following characters:—
Specific gravity.....0-8906 to 0*8920
Optical rotation
Acid value
Ester „

Total geraniol

after acetylation

+ 0° 30' „ + 0° 42'

1-2 „ 1-8

37-5 „ 51-6

272-7 „ 276-8

94-3 to 96 per cent.

The oil is soluble in 3 to 3-5 volumes of 60 per cent, alcohol.

Palmarosa oil contains free geraniol as its principal constituent to-

gether with a small but varying amount of esters of the same alcohol,

principally those of acetic and caproic acids. Methyl-heptenone is

present in traces, as well as the terpene dipentene. Flatau and Labbe

2

•claimed to have detected citronellal, but this is denied by Schimmel &
Co. Elze
3
states that farnesol is present in the oil.
Ginger grass or " Sofia " grass oil differs in characters entirely from
palmarosa or " Motia " grass oil. It has the following characters :—
Specific gravity 0-900 to 0-955
Optical rotation - 30° „ + 50°
Refractive index 1*4780 „ 1-4950
Acid value 2 „ 6
Ester„8 to 40 (rarely to 55)
„ „ (after acetylation).... 120 to 200
The oil is usually soluble in 3 volumes of 70 per cent, alcohol, but
generally becomes cloudy on the addition of more alcohol. Some
samples, however, do not appear to be soluble in 3 volumes, but re-
quire considerably more 70 per cent, alcohol to effect solution.
The known constituents of ginger grass oil are the terpenes, dipen-
tene, d-a-phellandrene and d-limonene, together with geraniol, and an
alcohol which is identical with that obtained by the reduction of perillic
aldehyde, and which is known as" perillic alcohol.
Walbaum and Hiithig
4
have isolated an aldehyde from the oil, having
ihe formula C 10 H 16 0, having the following characters:—
Boiling-point
Specific gravity.
Optical rotation.
Refractive index.
Oxime melting point.
Semi-carbazone melting-point
Phenylhydrazone „

221° to 224°

0-9351

+ 0°

1-47348

115° to 116°

169° „ 170°

63°

1

Bericht. October, 1914 ; April, 1915, 37. * Comptes rendus, 126 (1898), 1725.

8Chem. Zeit., 34 (1910), 857.

* Bericht, Schimmel & Co., April, 1904, 52; October, 1904, 41; April, 1905, 34.