Chemistry of Essential Oils

54 THE CHEMISTRY OF ESSENTIAL OILS

On fractionation the two oils gave the following results :—

157° to !67°

167° , 177 °

177°

187°

197°

240°

, 187°

, 197°

, 240°

, 252°

Residue

June Oil.

8 per (3ent.

27

20

3

7

6

29

December Oil.
13 per cent.
24
9
6
7
4
37
The oil contains Z-a-pinene, dipentene, sylvestrene, and a small
amount of bornyl acetate.
German distilled oil, which is obtained to the extent of 0'4 to 0'6 per
cent., has the following characters :—
Specific gravity.
Optical rotation.
Esters as bornyl acetate

0-865 to 0-888

+ 5° „ + 10°

1 to 4 per cent.

The oil is soluble in 7 to 10 volumes of 90 per cent, alcohol. On

fractional distillation 10 per cent, is obtained between 160° and 170°, and

about 45 per cent, between 170° and 185°. The ester value of the acety-

lated oil is about 15. (Austrian oils are sometimes slightly laevo-rotatory.)

The oil contains a-pinene, principally the dextro-rotatory variety,

d-sylvestrene, cadinene, the acetic ester of either borneol or terpineol and

probably dipentene. A small amount of free alcohol (borneol or ter-

pineol) is also present.

Swedish oil agrees in its characters with the German distillate.

2. Oil of Abies Sibirica.—This oil has of late years come into pro-
   minence on account of its high content in bornyl acetate, and its extremely
   low price. It is known commercially as Siberian " Pine " oil, although
   distilled from the leaves of Abies Sibirica (Abies pichta. Forb.). It is
   produced in North-East Russia, principally in the Wjatka district, very
   little being distilled in Siberia itself on account of the high cost of trans-
   port. The oil has a most fragrant odour and is highly esteemed as a
   cheap perfume.
   A pure oil has the following characters :—
   Specific gravity
   Optical rotation
   Refractive index
   Acid value
   Esters as bornyl acetate

0-900 to 0-928

• 30°,, -43°
  1-4700 „ 1-4730
  29 to 43 per cent.
  It is soluble in 1 volume of 90 per cent, alcohol or in 15 volumes of
  80 per cent, alcohol.
  Umney^1 has examined an apparently authentic sample of this oil,
  which had an exceedingly fine odour, and which had characters falling
  outside the above-mentioned limits. Its physical and chemical charac-
  ters were as follows :—
  Specific gravity 0-932
  Optical rotation - 41-2°
  Refractive index 1-4676
  Esters .......... 53*4 per cent.
  This oil contains a hydrocarbon,
  2
  distilling below 145°, of the formula
  C9H 4 , to the extent of from 3 to 4 per cent., which has been termed
  santene. This hydrocarbon boils at 140° and has a specific gravity =

(^1) p. and E.O.R., 1912, 289.^2 Aschan, Bericht, 40 (1907), 4918.