Chemistry of Essential Oils

58 THE CHEMISTRY OF ESSENTIAL OILS

" 3. A few days later another 60 Ibs. of leaves from the Oregon Douglas-

fir from Buckhold were distilled, and enough oil was then available for

further investigation. On fractionating the oil, an appreciable quantity

of geraniol was separated, and this appears to be the chief odorous con-

stituent. The proportion of total alcohols by acetylation calculated as-

geraniol is 31*5 per cent. The presence of bornyl acetate somewhat

masks the odour in the original oil. There is also a small trace of citral,

but the proportion is too small for determination. Geraniol occurs in

the oils of some species of Callitris in Australia, but has apparently not

been recorded as a constituent of the oils distilled from other conifers.

Geraniol is the chief constituent of Indian palmarosa oil obtained from

the fragrant grass Andropogon Schoenanthus Linn. (Cymbopogon Martini),.

and occurs in citronella oil, otto of roses, lemon oil, etc.

"OLL FROM THE LEAVES OF THE COLORADO DOUGLAS FLR.

"50 Ibs. of leaves of moderate-sized trees growing at East Liss,.

Hants, sent in October, 1919, yielded on distillation 0

*

31 per cent, of oiL

Specific gravity 0*905

Optical rotation - 46°

Refractive index (20°) 1*4717

Esters as bornyl acetate ...... 34*5 per cent.

" The terpenes consist principally of pinene. The odour is chiefly

due to the bornyl acetate present.

" It would appear from these analyses that the strong odour of

Colorado Douglas fir, which is like that of turpentine mixed with camphor,

is due to the large percentage of pinene and bornyl acetate. •

" In the Oregon Douglas fir, pinene is not present, and the bornyl

acetate is much less in percentage. The peculiar fragrance is chiefly

due to the presence of the highly odoriferous substance geraniol, slightly

modified by the small amount of bornyl acetate present."

7. The leaves and twigs of Pinus Sabiniana, the so-called digger pine,
   yield from 0078 to 0102 per cent, of essential oil having the following
   characters:—
   Specific gravity 0-851 to 0'857
   Optical rotation - 20° „ 39°
   Refractive index 14670 to 14671 at 15°
   Acid value 147 to 2-05
   Ester „ 677 „ 11-98
   ,, „ (after acetylation) .... 25*86 „ 37'16
   Schorger
   l
   has identified the following constituents in the oil:—
   n-heptane.
   Z-a-pinene.
   Mimonene.
   Bornyl esters
   Borneol

58 to 59

18

3-5

6

3 per cent.

8. The oil from the leaves and twigs of Pinus contorta, the lodge-
   pole pine, has the following characters :—
   Specific gravity 0*869
   Optical rotation
   Refractive index
   Acid value
   Ester „

- 17*84°

1*4831

0*9

6*02

, (after acetylation) 32-3

(^1) Jour. Ind. Eng. Chem. (1915), 7, 24.