324 THE CHEMISTEY OF ESSENTIAL OILS
to 0 * 08 per cent. The odour of the brownish-yellow oil differs distinctly
from that of the fruit. d 150 0-9273; aD - 0° 48'; acid number 16-2;
ester number 148'6; ester number after acetylation 195*9; soluble in
1*1 volume 80 per cent, alcohol; when more solvent is added opal-
escence and strong separation of paraffin occur. For comparison we
give below the properties of two oils distilled from the fruit only.
- Yield (compared with dry material) 0-9 per cent.; d 15 o 08744 ;
aD + 0° 38'; acid number 15'9; ester number 215-4; ester number
after acetylation 2853 ; soluble in 0
- 8 and more volume 80 per cent,
alcohol; not entirely soluble in 70 per cent, alcohol.
- Yield (calculated on dry material) 1-21 per cent.; dl (^5) o 0-8798 ;
AD + 1° 6'; acid number 7'3 ; ester number 2424; ester number after
acetylation 276'3; soluble in 1 and more volume 80 per cent, alcohol.
The oil from the dry, ripe fruit of Heracleum giganteum L. (yield
3 6 per cent.) has the following characters:—
Specific gravity 0872 to 0-875
Optical rotation + 1° to + 1° 30'
Kefractive index 1-4230 „ 1-4255
Acid value 1-5 „ 4 0
Ester „ 280 „ 290
„ „ (after acetylation) 314 „ 320
It contains the acetic and butyric esters of hexyl and octyl alcohols,
and traces of ethyl butyrate.
The colourless oil had a peculiar odour, similar to that of common
heracleum oil.
OLL OF BUPLEUKUM FBUTICOSUM.
The oil of this umbelliferous plant, which grows wild abundantly in
the island of Sardinia, has been examined by Francesconi and Sanna.
1
It has the following characters :—
Specific gravity 0831 to 0'869
Rotation + 19° ,, + 47°
Refractive index 1-4783 „ 1-4862
Saponification value 5 ,, 14
„ „ (after acetylation)... 23 ,, 285
The yield varied from 0'5 to 4*4 per cent. The oil consisted chiefly
of hydrocarbons; it contained only small proportions of alcohols and
esters. It was found that the oil-content increases as the plant reaches
maturity, and that the flowers contain more oil than the leaves. Plants
gathered at high altitudes contain more oil than do those from the plains.
The density, optical rotation and index of refraction increase as the plant
develops; they attain their maximum during the flowering period, at
the end of which they diminish again. The ester-content of the leaves
diminishes during the flowering and is greatest in the plants from the
mountains. The leaf-oils contain more ester than do the flower-oils;
plants grown in a moist atmosphere are deficient in ester. The specific
gravity of oils rich in ester is higher, and their rotatory power lower
than that of oils which are deficient in ester. The flowers contain a
larger proportion of free alcohol than the leaves, and during the flower-
ing period the content of free alcohols increases at the expense of that
of the alcohols in combination. The terpene present boils at 167° to
1
Gazz. Chim. Hal., 41 (1911), i. 395.
