A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS 281
nitric acid of specific gravity 1'33, until a reaction commences, and
then keeping the liquid for half an hour jnst at the boiling-point Ou
cooling, muric acid separates out in small crystals. From the motherliquor
more may be obtained by boiling it with nitric acid. Mucic
acid is but sparingly soluble in cold water, and can therefore easily
be separated from saccharic acid, which is often produced together
with tnuric acid by oxidizing several kinds of sugar and gum, By
the prolonged action of nitric acid it is oxidized to racemic acid and
oxaUc acid; hydriodic acid reduces it to adipic acid C.H^CO.OH)^
When mucic acid is heated with phosphorus pentachloride, it yields
the compound C4H2C12(COC1)S:—
C4H4(OH)41 g^H + 6PC16 = C4H.,C12 { °°g{ + 6POC13 + 8HC1
This chloride is decomposed by water, ckloromueonic add
C4HjClsj(CO.OH)g being formed, crystallizing in long white needles.
On heating this acid with alcoholic potash to 173°, it is resolved into
hydrochloric acid, oxalic acid, and acetic acid.
Hydromuconic add C4H0(C0.OH)8 is obtained by treating chlorormiconic
acid with water and sodium-amalgam; it .crystallizes in
white needles, melting at 195°. By the further action of nascent
hydrogen it is converted into adipic acid. When bromine is added
to a solution of bydroroucouic acid in glacial acetic acid, it yields
dibromadipze acid, C4H6Br2(CO.OH)2, crystallizing in small warty
needles. On adding silver oxide to its hot aqueous solution, the
following reaction takes place .•—
CBH8ttA + Ag2O = C.H.O, + H8O + 2AgDr
Mitcouic • add OgH/)^ is produced, forming large monoclinic
crystals, It is a monobasic acid, which on boiling with baryta water
yields carbon dioxide, acetic acid, succinic acid, and other products.
The formation as well as the products of decomposition of this acid
show that its constitution must be similar to that of aconic acid
(page 239), and may be expressed thus;—
*> C—CHj-CH,—CO.OH
PVRO MUCIC ACID CBH4OS
Is a product of the destructive distillatiou cf nmcic acid, hut is
more conveniently obtained by decomposing its aldehyde with
alcoholic potash. Pyromncic acid is a monobasic acid, and crystallizes
in flat needles, melting at 134°.