TNT: Trinitrotoluenes and Mono and Dinitrotoluenes

THE MANUFACTURE OF TNT 31
comparatively safe, it is made primarily to explode.
Now, the more care taken with the manufacture of
TNT—the less explosions in the plant, and the more
explosions out of the plant.
There are three general processes for the nitration
of toluene to TNT. These are the one-stage, the twostage,
and the three-stage. All of these are being used
at present in North America, but the three-stage seems
to have the greatest preference. As the names imply,
the process involves either one, two or three separate
nitrations to carry the toluene to TNT. In some
respects, the names " one-stage/' " two-stage/' etc.,
are misleading, because in every preparation of TNT,
whether it be by the one-stage, the two-stage or the
three-stage process, there are three distinct nitrations.
With the one-stage process these three nitrations are
all effected with the one acid mixture and without
separation of the nitro-derivatives and the spent acid
until the TNT is completed. Similarly, the twostage
and the three-stage processes accomplish the
same thing in either two or three different steps, each
step necessitating separation of the spent acid, and the
addition of fresh acid. It must not be supposed,
however, that the entire amount of the toluene is converted
to mononitrotoluene before any of the monois
nitrated to dinitrotoluene, or that all of the mononitrotoluene
is nitrated to dinitrotoluene before the
di- is nitrated to TNT. This ideal result is not obtained
with even the three-stage process. No matter which
of the three processes is used, there will always be more
or less impurities existing at each stage in the form of
higher or lower nitration products.
The toluene which is to be used as the raw material