CONIFEE^ 53
The oil was almost free from compounds containing oxygen, and esters,
alcohols, aldehydes, and similar bodies were practically absent, only ,a
very small amount (about 1 per cent.) of an alcohol being determined by
acetylating the oil. The higher boiling liquid portion showed no ten-
dency to resinify, so that when the semi-solid crystalline mass, which
contained the diterpene, was spread upon porous plates for a few days,
the whole of the liquid portions were absorbed, the diterpene remaining
in a perfectly white, and even at this stage, almost pure condition. It
' was slightly soluble in cold alcohol, but more readily in hot alcohol, and
dissolved easily in chloroform, ether, petroleum ether, and benzene.
The best method for purification, after the first separation from alcohol,
was to dissolve it in chloroform and precipitate by the addition of al-
cohol. If the chloroform was in excess, so that on the addition of
alcohol no precipitate was formed, then, on slow evaporation, crystals
readily separated. These crystals were microscopic needles, but were
not well defined. When "only a small amount of chloroform was used
as solvent, then on addition of the alcohol the solid substance at once
crystallised out. When this was dried it had more of a tabular struc-
ture, was pure white, of a nacreous lustre, and was practically without
odour. It was dextro-rotatory, and the determination of the specific
rotation was made with both benzene and chloroform, the specific rota-
tion, [a]D = + 16*06°, being identical with both solvents. Its ready
solubility in benzene enabled the molecular weight to be determined by
the cryoscopic method, and this, together with the results of the analy-
ses, showed it to have the formula, C 20 H 32. Its melting-point was 95
°
C. (cor.), and it did not matter what the solvent had been. The fused
substance also melted again at the same temperature. This diterpene
has been named phyllocladene.
THE PINE-NEEDLE OILS.
It will be convenient to deal with the oils obtained from the leaves
of various species of Pinus, Larix, Abies, and certain closely allied
plants, under the general description of pine-needle oils. A consider-
able number of these have been examined, but only a few are commer-
cial articles.- Oil of Pinus sylvestris.—The oil distilled from the leaves of this
tree varies in character to some extent, according to the locality in
which the tree is grown.
English distilled oil is laevo-rotatory, whilst most other varieties are
dextro-rotatory. It has the following characters :—
Specific gravity 0'885 to 0-890
Optical rotation - 7° „ - 22°
Esters as bornyl acetate 2'5 to 4 per cent.
Umney1 examined samples distilled in summer and winter, and
found that the two specimens had the following characters:—
Distilled Distilled
in June. in December.
Yield
Specific gravity 15° C0'88 5 0
Optical rotation (100 mm.).
Percentage of bornyl acetate
(^1) Pharm. Jour., 55 (1895), 161, 542.
0-5 per cent.
0'885
- 19°
3'5
0*133 per cent.
0'889- 7-75°
2-9