A Manual of the Chemistry of the Carbon Compounds

454 THE CHEMISTRY OF
A 0 -
2H2
Dimethyl-anthracene has the greatest resemblance to anthracene;
it melts at 200°, and sublimes in white plates, exhibiting a bluishviolet
fluorescence.
Anlhraeenecaiionic Add CUH,,.CO2H.—This compound stands in
the same relation to anthracene as benzoic acid to benzene; it is produced
by heating anthracene with carbonyl chloride to 200° for ten
hours, and digesting the product with dilute sodium carbonate. It
crystallizes from alcohol or hot water in needles, melting at 206°, but
being slowly resolved at the same time into anthracene and carbon
dioxide; this decomposition takes place quickly by heating it with
soda-lime. A solution of chromic trioxide in acetic acid oxidizes it to
anthraq[unione :—
CMH0.CO2H + 30 = CMH8O2" + CO2 + H2O
PYBENE CWH1O.
When coal-tar is distilled until only coko is left in the retort, a
yellow greasy substance passes over towards the end. By treating it
with carbon disulphide, pyrene is dissolved. It is purified by recrystallizing
repeatedly from alcohol, and then mixing its cold alcoholic
solution with a solution of picric acid. The red crystalline precipitate
C,QH,0 + CJEIgtNO^jOH thus obtained is decomposed with ammonia,
and the hydrocarbon crystallized from alcohol,
Pyrene is obtained by the slow evaporation of its solution in
rhombic plates melting at 142°.
Heaxihydropyrene C,8HW is produced by heating pyrene with strong
hydriodic acid and amorphous phosphorus to 150°. It crystallizes
from alcohol in needles or prisms, melting at 127°, and does not combine
with picric acid. At a red heat it decomposes into pyrene and
hydrogen.
Nitropyrcnc 0WH9.NO, is readily formed by heating pyrene with