36 THE CHEMISTEY OF ESSENTIAL OILS
The oil contains d-a-pinene, d-camphene, d-sylvestrene, a ketone
resembling thujone, terpinyl esters, a sesquiterpene, cedrol, and alcohols
which have been investigated by Schimmel & Co.^1 with the following
results:—•
The principal constituent of the mixture is an alcohol, terpinenol-4
of the formula C 10 H 18 O. Sabinol is possibly present in the alcohol
mixture, but has not been characterised with certainty. A third alcohol
is present which has the following features:—
It is esterifiable with benzoyl chloride (using pyridine) and was re-
covered from the steam-distillation residue by saponification. For pur-
poses of purification it was again treated with phthalic anhydride at
an increased temperature. Unfortunately, in this manipulation part of
it was decomposed. The pure alcohol C 10 H 18 O has a pleasant, rose-
like odour. Its constants were as follows: boiling-point 76° to 77°
(4 to 5 mm.), 210° to 212° (ordinary pressure), d 15 o' O9422, aD + 43° 38'
WD 20 O i'46678.
With phenyl and naphthyl ^socyanates only liquid derivatives were
obtained. No diphenylurethane was formed. Judging by the odourr
oxidation with Beckmann's mixture appears to give rise to an aldehyde.
With regard to the cypress oil fractions with the highest boiling-point,,
which possess in a more pronounced degree the peculiar balsamic odour,
it would appear that they contain, besides cadinene and cypress-camphor,
a sesquiterpene alcohol, boiling at 13.6° to 138° at 5 mm. pressure.
THUJA-LEAF OIL.
This oil is obtained by distillation with steam of the leaves and pos-
sibly also the small twigs of Thuja occidentalis, the well-known Arbor-
vitce, sometimes also called the white cedar. The yield of oil is from
0*4 to 1 per cent. It is almost colourless, but by oxidation becomes,
slightly greenish or yellow. Its odour is not particularly pleasant,
somewhat recalling that of tansy oil. It is frequently adulterated with
cedar oil, pine-leaf oils, and turpentine. The earliest scientific investi-
gations of this oil are those of Schweizer and Jahns,^2 but that of
Wallach,
3
undertaken when our knowledge of the group of compounds
contained in the oil was a little more advanced, is now the standard
work. The chief constituents of the oil are a-pinene, laevo-fenchone
C 10 H 16 O, and the isomeric ketone, dextro-thujone, which also occurs in
the oils of tansy, wormwood, and sage. Traces of esters, probably of
acetic and formic acid, are also present. A small quantity of laevo-
borneol or its esters is also present. The highest boiling constituents
of the oil have not yet been thoroughly examined, but Wallach believes
them to contain the last-named body in the inactive form.
Carvotanacetone was isolated from the oil by Wallach during a
fractional distillation, but it is probable that this is the result of the
action of heat on the thujone present, and that it is not a natural con-
stituent of the oil.
Pure thuja-leaf oil has the following characters :—
Specific gravity 0-910 to 0'935
Optical rotation
Acid value
Ester „
,, (after acetylation)- 5° „ - 15°
0 „ 1
18 „ 25
about 40
1
Report, April, 1913, 50.
2Jour, 3 prakt. Chem., 30 (1843), 376 ; Arch. Pharm., 221 (1883), 749.
Annalen, 272 (1892), 99.