A Manual of the Chemistry of the Carbon Compounds

TB3 CARBON COMPOUNDS. 163
has formed at the same time remains undissolved. The solution of
the sodium salt is evaporated, and the residue decomposed by dilute
sulphuric acid. The acid, which separates out as a light oily layer, is
dried over calcium chloride and rectified. Valerianic acid is a thin
oily liquid, possessing a sour smell of rotten cheese, and boiling at
175°. It combines with water, forming a hydrate C5H1OO2 + HgO,
which boils without decomposition.
This acid has also been prepared by synthesis, and is formed by
heating secondary propyl iodide with aodacctic ether:—
CH8Na
CH, CH, L»
+ CHI = Nal + CH—CHS-CO
CH8 CHS 6
Ethyl valerate is thus obtained, which is easily decomposed by
alkalis.
Another synthesis consists in distilling sodium isobutylsulphate
with potassium cyanide, by which read ion valeronitrile C6H,,N is
formed, which, on heating with caustic potash, yields potassium
valerate. Most of the salts of valerianic acid are soluble in water,
in the dry state they are odourless, bnt in the moist state they smell
of the acid.
Zinc Valerate (CjIIoO^Zn forms scaly crystals, and is not very
readily soluble in water, but dissolves easily in alcohol: it is used in
medicine.
Silver Valerate C^HgOgAg is u white precipitate, which can be recrystallized
from boiling water.
CH 01
AmylValerate A -A VO is obtained, besides valerianic acid, by the
oxidation of amyl alcohol. It is a liquid, boiling at 188°,and possessing
an odour like apples. It is used by confectioners, and called
"apple oil,"
The amyl alcohol possessing rotating power yields on oxidation,
besides some carbon dioxide and acetic acid, a valerianic acid, which
differs from that just described in different ways. It is optically
active, turning the plane of polarized light to the right, whilst the
alcohol turns it to the left. The same acid is formed by the putrefaction
of albuminous substances, and is therefore found in old cheese.
It boils at 170°, and forms salts which have the same composition and
properties as those of the inactive acid, with the exception of the
barium salt, which does not crystallize, but dries up to an amorphous
mass, whilst that of the inactive acid crystallizes easily inlnrge plates.
Secondary Amyl Alcohol ( CH8 ^1-CH.OH, or Methyl-isopropyl
foW.—WIIPII amyl alcohol is heated with zinc chloride, water
ami avii/lnie 0,,H10 are formed. This hydrocarbon combines with
faniiiu* h\diiodic ucid, and vields seeomfari/ aun/l to>li>h .—
M 2