_Camphor._--The compound obtained from the oil by refrigeration was
a soft, white, granular, crystalline mass, and possessed a distinct
camphorlike odor and slightly bitter camphoraceous taste. The crystals
sublimed readily and melted at 174° to 176° C. The boiling point of
the compound was 205° C., and the rotation in a 50 mm. tube of 20 per
cent solution in alcohol was found to be +3.8°, 20 percent solution of
commercial camphor in alcohol rotating +3.5°. It was readily soluble in
alcohol and the other organic solvents.
To further identify the crystals with ordinary camphor two compounds
were prepared, the semicarbazone and the oxime, with which camphor
forms definite chemical compounds. The semicarbazone was prepared
according to the method of Tiemann. (See p. 17.) The crystals obtained
after recrystallization from alcohol melted at 237° to 239° C., pure
camphor semicarbazone melting at 236° to 238°. For the preparation of
the oxime Auwers’ method was applied. (See p. 16.) Recrystallized from
ether the oxime melted at 117° to 118° C., whereas pure camphor oxime
melts at 118° to 119° C.
Since the physical and chemical properties of this substance correspond
almost identically with those of camphor, it may be safely stated that
the crystals are those of commercial dextro camphor.
_Aldehyde constituent._--From the pungent and penetrating odor and the
strong reducing properties of the first fraction, which, as shown in
Table V, distilled largely below 80° C., there would seem to be the
possible presence of a trace of formaldehyde.
_Cineol, or eucalyptol._--Qualitative tests as indicated in Table
V show the presence of cineol in fractions from 170° to 205° C.,
the characteristic crystalline cineol addition product of iodol
corresponding in melting point to the pure cineol iodol. Cineol was
further identified in these fractions by the preparation of cineol
hydrobromid prepared by passing dry hydrobromic acid gas into a
well-cooled solution of the oil in petroleum ether. A crystalline
hydrobromid was obtained from each fraction which gave the iodol
reaction. The hydrobromids prepared melted between 55° to 57° C., while
pure cineol hydrobromid is reported as melting at 56° to 57° C.
Since the presence of cineol in the several fractions of the oil
was proved, a quantitative estimation was deemed desirable. Because
of the smallness of the individual fractions the hydrobromic acid
method was adopted in this estimation, it being the most accurate
when cineol is present in only small quantities. The phosphoric acid
method is best adapted to oils which are very rich in the compound.
The hydrobromic acid method has been used in the assay of eucalyptus
oils,[35] and consists essentially in conducting dry hydrobromic
acid gas into a solution of the oil in about twice its volume of
petroleum ether, the solution being well cooled by a freezing mixture,
separating the crystals on a force filter, washing and decomposing
with water, and measuring the cineol formed. A slight deviation was
made from the directions on account of the smallness of the fractions
and consequently the small amount of hydrobromid obtained, which when
decomposed with water would introduce an error. After the hydrobromid
of cineol was obtained in each case and washed it was weighed and the
percentage of cineol was calculated from the weight of the crystals
from a given quantity of each fraction. In this manner by assaying the
four fractions which gave qualitative tests there was found to be a
total of 19.8 per cent of cineol in the oil.
_Borneol._--By oxidation of fraction 233° to 260° C. with a 3 per cent
solution of potassium permanganate, slightly warming and allowing it
to stand for 12 hours, then shaking out the mixture with ether and
allowing the ether to evaporate, a mass of crystals remained which
proved to be camphor. It is possible that borneol was present in this
fraction, as borneol is readily oxidized to camphor with ordinary
oxidizing agents. Since the preliminary chemical examination of the oil
indicated a small percentage of esters and of free alcohol, the alcohol
was probably borneol.