The Chemistry of Powder and Explosives - Sciencemadness Dot Org

178 AROMATIC NITRO COMPOUNDS
lized from alcohol. Pure tetryl melts at about 129.4°; a good commercial
sample, at about 128.5°.
The nitration of aniline in the presence of a large amount of
strong sulfuric acid results wholly in the formation of m-nitroaniline,
but the similar nitration of dimethylaniline gives principally
a mixture of the ortho- and para-derivatives. Monomethylaniline
stands between aniline and dimethylaniline in
respect to the orienting effect of its amino group; it yields a
considerable amount of the m-nitro- compound—and dimethylaniline
is preferred for the preparation of tetryl. Commercial
dimethylaniline contains a certain amount of monomethylaniline,
from which it is extremely difficult to free it, and this in the
manufacture of tetryl is converted in part into 2,3,4,6-tetranitrophenylmethylnitramine,
or m-nitrotetryl, pale yellow, almost
white, crystals from benzene, m.p. 146-147.° 87
CH3 3 H CH3 H CH3 NO2 CH3 CH3 NO2
V V V
I
V
I
3
» H20 ]
J-NO2 i I
H,o
J-NO2 J-NO, I \ J-OH / °
NO2
NO,
No m-nitrotetryl is produced if pure dimethylaniline is used in
the usual process for the manufacture of tetryl. The amount of
this impurity in the usual process depends upon the amount of
monomethylaniline which may be present. A large excess of
sulfuric acid tends toward the production of m-nitro compounds,
but a reduction in the amount of sulfuric acid is not feasible for
this increases the amount of benzene-insoluble material. m-Nitrotetryl
reacts with water, as TNA does; the nitro group in the
3-position is replaced by hydroxyl, and m-hydroxytetryl or
2,4,6-trinitro-3-methylnitraminophenol, yellow crystals from
water, m.p. 183°, is formed. This substance resembles picric acid
and forms explosive salts. It is readily soluble in water, and
87 Van Romburgh, Rec. trav. chim., 8, 274 (1889). Van Romburgh and
Schepers, Versl. Kon. Akad. Wetenschapen, 22, 293 (1913), also prepared
this substance by thje nitration of dimethylaniline (in 20 times its weight of
concentrated sulfuric acid).