A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 283
pyrrolic acid C^B^NO., which is obtained as a white flocculent precipitate
on adding hydrochloric acid to the solution; it crystallizes
from alcohol in white prisms, and sublimes at 190° in small feathery
crystals. At a high temperature it is resolved into carbon dioxide
and pyrrol, which is also readily obtained by heating ammonium
pyromucate with glycerin, Pyrrol is a colourless oil, when freshly
prepared, but it soon assumes a brown colour; it boils at 133°, and
possesses a pleasant smell. Pyrrol has the characteristic property of
imparting a fine crimson colour to pine-wood, moistened with hydrochloric
acid. This pyrrol4ed has the empirical formula C^B^Oj; it
is also obtained as an amorphous precipitate by heating pyrrol with
an excess of hydrochloric acid, and by the action of acids on tetraphenol
and furfuryl alcohol.
Potassium dissolves in pyrrol with evolution of hydrogen, potassium-pyrrol
CJLKN being formed, which, with ethyl iodide, yields
dhyl-pyrrol CgH^C^JN, a colourless liquid smelling like turpentine;
its vapour colours pinewood, moistened with hydrochloric acid
like pyrrol.
The constitution of the compounds derived from mucic acid is not
exactly kno-wnj the relation between them may be expressed by the
following formula! :—
Adipic Acid. Mucic Acid. Pyromudc Acid.
C « H a{cO.OH 0 * H «( OH )*{co:OH C4H3O.CO.OH
Cnrboyyrrolamide. Carbopyirolic Acid. Pyrrol.
C4H3(NH)CO.NH8 C4H8(NH)CO.OH C4H4.NH
CHELIDONIC ACID AND MECONIC ACID.
Chdidmiic Add CJIfCO.OH)^—This tribasic acid occurs, together
with malic acid, in Cliclidoninm wuytavaud is obtained by heating the
jnice of this herb to the boiling-point, filtering and acidifying the
liquid with nitric ncid, Ou adding lead-nitrate, a crystalline precipitate
of lead, chelidonate, is formed, which is decomposed by hydrogeo
sulphide. Chelidonic acid is sparingly solnble in cold, bnt readily in
hot water, and crystallizes in colourless needles. By the action of
bromine it is decomposed, yielding bromoform and pentahvmacetone
CsHBr6O.
Meeonic acid C4HO(CO.OH)3 is foand in combination with morphine
and other bases in opium; its calcium salt is obtained as a byproduct
in the manufacture of these alkaloids, On decomposing this
salt with hydrochloric acid, impure ineconic acid separates out, which
is purified by converting it into the ammonium salt, which is crystallized,
and then again decomposed with hydrochloric acid.
Meconic acid crystallizes from a hot aqueous solution in scales or