A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 299
The camphors contain oxygen, and most of them exhibit the
character of alcohola
Most of the terpenes, as well as camphors, exist in plants as essential
or volatile oik.
OIL OF TURPENTINE Ol0H10.
All the trees belonging to the order Coniferse contain resins and
liquid hydrocarbons; a mixture of both exudes as an oleo-resinous
juice from the barks of these trees, and is called turpentine. When
turpentine is distilled; either alone or with -water, the hydrocarbons
volatilize, and resin is left behind.
Oil of turpentine is obtained from different species of Pinus and
Abies; it is a limpid, mobile liquid, with the specific gravity 0,89,
and boiling at 160°. It is almost insoluble in water, bat readily
dissolves in strong alcohol and glacial acetic acid; with ether and
absolute alcohol it mixes in any proportion, Oil of turpentine
dissolves sulphur, phosphorus, resins, and many other bodies which
are insoluble in water. It readily absorbs oxygen, converting it into
ozone, which gradually oxidizes the oil, forming resinous products.
The oils of turpentine of different origin exhibit considerable
diversities in their optical properties. The French oil (from Pinus
maritima), as well as the oils from Pinus Laricc a.nd Abies pectinata,
tarn the plane of polarization to the left, whilst English turpentineoil
(from Pinus auMralis) turns it to the right.
These different varieties are converted into new optical modifications,
by repeated distillation or by the action of acids. It also appears
that the oil contained in the plants is different from that which is
obtained by distillation. Thus, on distilling the young branches of
the pine with water, an oil is obtained possessing an agreeable
odour, which is ohanged into that of the common oil by distilling it
over potash.
When oil of turpentine is boiled with dilute nitric acid, it is
oxidized to acetic acid, propionte acid, butvrio acid, oxalic acid, terebio
acid, and other compounds. Terebie acid C7HloO4 crystallizes in
colourless prisms, and is resolved by heat into carbon dioxide and
pyrotmbk acid C8HBO2 (see page 270).
Terpin or ffydmte of Turpentine-oil C1OH2OO2 + H?O.-r-Ofl of
turpentine slowly oombineswith water, forming terpin; this combination
takes place more quickly if an acid he present. To prepare this
compound, eight volumes of the oil are mixed with two volumes of
weak nitrio acid and one volume of alcohol; the mixture ia exposed
to the sunlight, and frequently shaken. Terpin crystallizes in large
iliombio prisms, melting at 100° with loss of one molecule of water;
the anhydrous compound sublimes at 150° ia needles, It is sparingly
soluble in cold water, but dissolves freely in alcohol and in boiling
water.