In order to identify the crystalline substance obtained from the oil,
a small quantity was sublimed, and the usual tests of melting point,
boiling point, and rotation were applied. For further recognition of
the compound, an attempt was made to prepare an oxime. Accordingly the
method of Auwers[25] was applied, which, briefly, is as follows: To
a solution of 10 parts of camphor in 10 to 20 times the amount of 90
per cent alcohol is added a solution of 7 to 10 parts of hydroxylamine
hydrochlorid and 12 to 17 parts of a soda solution. If turbidity
results, more alcohol is added and the mixture is heated on a water
bath until a small portion of the solution remains clear upon the
addition of water or until the resulting turbidity disappears, when
a few drops of soda solution are added and no free camphor remains.
The mixture is then diluted with water, filtered if necessary, and
neutralized with dilute hydrochloric acid. The camphor oxime which
separates is recrystallized from alcohol or ligroin. It melts at 118°
to 119° C.
The above method applied to the sublimed crystals resulted in the
formation of an oxime which melted at 120° to 124° C. Since an oxime
was obtained (indicating possible ketonic characters), application
was made of another reaction for ketones, namely, the formation of
semicarbazone. Tiemann’s method[26] for the preparation of camphor
semicarbazone was applied. The method is as follows: 1.5 grams of
camphor dissolved in 2 cubic centimeters glacial acetic acid are
treated with a solution of 1.2 grams of semicarbazid hydrochlorid and
1.5 grams of sodium acetate in 2 cubic centimeters of water. Water is
added and the crystalline compound recrystallized from alcohol. The
melting point of camphor semicarbazone is 236° to 238° C.
The sublimed crystals when treated in the above manner yielded a
semicarbazone which melted at 232° C.
For a comparison of this substance with pure camphor, a tabulation was
made of the more common physical properties and chemical tests.
+Table I.+--_Comparison of properties of crystals from oil of black
sage and of pure camphor._
---------------+-------------------------+------------------------
Test. | Crystals from | Crystals of pure
| oil of black sage. | camphor.
---------------+-------------------------+------------------------
Melting point. | 174° to 175° C. | 175° C.
Boiling point. | 205° C. | 204° C.
Rotation in | +3.33° (20 per cent | +3.51° (20 per cent
50 mm. tube. | solution in alcohol). | solution in alcohol).
Oxime. | M. p. 120° to 124° C. | 118° to 119° C.
Semicarbazone. | M. p. 232° to 233° C. | 236° to 238° C.
---------------+-------------------------+------------------------
The table shows very close similarities in the melting point, boiling
point, and rotation of the crystals from the oil of black sage and of
pure camphor. The melting points of the oximes and semicarbazones,
though not corresponding so well, seemed to indicate that the crystals
were in all probability camphor. To further confirm the assumption that
the compound from the oil was camphor, an elementary analysis of the
compound was made after being twice sublimed.
0.1273 gram of crystals gave 0.1199 gram H_{2}O, corresponding to
10.5 per cent hydrogen.
0.1273 gram of crystals gave 0.3228 gram CO_{2}, corresponding to
79.7 per cent carbon.
C_{10}H_{16}O/camphor requires { 79 per cent carbon.
{ 10.5 per cent hydrogen.
0.1279 gram of crystals gave 0.1244 gram H_{2}O, corresponding to
10.8 per cent hydrogen.
0.1279 gram of crystals gave 0.3761 gram CO_{2}, corresponding to
79.9 per cent carbon dioxid.
The combustion results seemed to indicate that the compound is
identical with that of camphor, as the above tabulation also clearly
shows.