A Manual of the Chemistry of the Carbon Compounds

220 THE CHEMISTRY OF
the boiling-point and filtered. On cooling, crude sncoinic acid crystallizes
out, which is easily freed from adhering empyreumatie oils by
heating it with nitric acid.
It may also conveniently he prepared from the crude calcium salt
of malic acid, which can be procured in large quantities from, the unripe
berries of the mountain ash or from rhubarb-stalks (see Malic
Acid}. On adding six parts of water and a. fourth part of brewer's yeast
to this salt, and keeping the mixture at a temperature of 30°^—40° for
a few days, carbon dioxide is evolved and acetic acid and calcium
succinate are formed, probably according to the following two
reactions:—
(1) 0tH6O6 + H20 = O,H4Ot + 2CO, + H3
(2) 0^0, +H, =C4Hu04 + H2O
To obtain the free acid, the calcium salt is decomposed by sulphuric
acid.
Succinic acid crystallizes in monoclinic prisms, melting at 180*
and decomposing at 235° into water and succinic anhydride. It is
soluble in about twenty-three parts of cold water and very readily in
boiling water. By passing a galvanic current through a concentrated
solution of potassium succinate the acid is decomposed into ethene,
carbon dioxide, and hydrogen:—•
"When an aqueous solution of the acid containing an manic salt is
exposed to sunlight it splits up into propionic acid and carbon
dioxide;—
The sucoinates of the alkali-metals are readily soluble in water;
those of the other metals either sparingly soluble or insoluble. By
adding a neutral solution of ferric chloride to a neutral succinate a
brown gelatinous precipitate of ferric succinate is formed. This reaction
is made use of for the detection of this acid and for the separation
of iron from manganese.
f C H
JSthyl Shtetinate C«H4O4-< Q 2 TT B is a colourless, oily liquid, insoluble
in water, and boiling at 217°. It is obtained by passing hydrochloric
acid gas into a solution of succinic acid in alcohol.
f C H
Eihylsuccmic Acid C4H4Ot-J X s is produced by heating succinic
anhydride with absolute alcohol. It is a syrupy, sour liquid, soluble
in water and forming soluble salts.
Smxinic Anhydride C4H4OS is most conveniently prepared by distilling
succinic acid with phosphorus pentoxide. It forms shining