396 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVESmixtures. This can be seen in the diagram (Fig. 102) illustrating the nitration ofmixtures. This can be seen in the diagram (Fig. 102) illustrating the nitration of
DNX to TNX. The quantity of N 2 O 3 evolved during the reaction was taken as
a criterion of the intensity of the oxidation reactions.a criterion of the intensity of the oxidation reactions.
FIG. 102. Oxidation of dinitroxylene as a function of the concentration of sulphuric
acid in nitrating mixtures (Gorst [2]).Ortho- and para- xylenes are particularly easy to oxidize. One of the reasons
why TNX has not been more widely used as explosive is that it is difficult to isolate
m-xylene from the corresponding light oil or petroleum fractions (p. 406). Owing
to the presence of its isomers commercial m-xylene, when nitrated, gives a mixture
of nitro compounds, often containing oily components that exude easily and which
are highly undesirable where a high purity product is required (e.g. for filling shells).
In addition to this, trinitro-m-xylene has other disadvantages, viz.: its high melting
point, which makes it difficult to fill shells by pouring, and its relatively low explo-
sive power, which corresponds approximately to that of dinitrobenzene. An
advantage of TNX is its low toxicity.
In spite of its drawbacks, during World War I France, Russia, and the United
States used commercial trinitroxylene as an explosive, mostly in mixtures with other
nitro compounds, or with ammonium nitrate, when these countries were short of
nitration grade toluene. In the period between the two World Wars trinitroxylene
was manufactured in the U.S.S.R and France and on a small scale in Poland.
Trinitroxylene is known as Ksilil (U.S.S.R.), Xylite (France), Ksylit (Poland)
and TNX.
The commercial product, according to Kravchinskii [3], melts partially at 120-
125°C and completely at 160-177°C, and solidifies at 160-162°C, while chemically
pure 2,4,6-trinitro-m-xylene melts at 182°C.
The grades of commercial TNX as classified by their melting points are:
I grade m. p. 170°C
II grade m. p. 160-162°C
In addition grade III trinitroxylene may also be available. This is an oily product used
like nitrated solvent-naphtha, for special purposes (e.g. in coal mining explosives).