The Chemistry of Powder and Explosives - Sciencemadness Dot Org

PICRIC ACID 163
a yellow nitrophenolate of mercuric nitrate. By the continued
action of the acid this is nitrated to the trinitrophenolate and
decomposed with the formation of picric acid and the regeneration
of mercuric nitrate. 06
OHgONO, OHgONO, OH
NOr/\-NO,
NO, NO,
The addition of mercuric nitrate is here written as a 1,4-addition,
but 1,2-addition would give the same final product, and there is
no evidence in the facts concerning benzene which enables us to
choose between the alternative hypotheses. Toluene yields trinitro-m-cresol
by a similar series of reactions, and it is clear that
the nitro group in the addition product of mercuric nitrate and
toluene has taken either the 2-, the 4-, or the 6-position, that is,
one or the other of the positions activated by the methyl group.
In the addition of mercuric nitrate to naphthalene, the nitro
group correspondingly may be supposed to go to the active
a-position. If the addition is 1,2-, the product on oxidation will
yield a derivative of /3-naphthol. If it is 1,4-, it will yield a
derivative of a-naphthol. The two possibilities are indicated below.
H.. H NO2 NO,
H _
H NO, NO, NO,
H OHgONO, OH OH
Gentle treatment of naphthalene with, nitric acid containing
mercuric nitrate yields, 2,4-dinitro-a-naphthol in conformity
with the belief that the first addition product is 1,4- as represented
by the second of the above formulations.
Picric acid was obtained in 1771 by Woulff, who found that
56 Davis, Worrall, Drake, Helmkamp, and Young, J. Am. Chem. Soc, 43,
594 (1921); Davis, ibid., 44, 1588 (1922). Davis, U. S. Pat. 1,417,368 (1922).