The Chemistry of Powder and Explosives - Sciencemadness Dot Org

TRINITROTOLUENE 143
?mall amount, perhaps 2 per cent, of this material which has
escaped further nitration. The substance is stable and less reactive
even than a-TNT, and a small amount of it in the purified
TNT, if insufficient to lower the melting point materially, is not
regarded as an especially undesirable impurity. The principal
impurities arise from the m-nitrotoluene (b.p. 230-231°) which is
formed to the extent of about 4 per cent in the product of the
mononitration. We omit discussion of other impurities, such as
the nitrated xylenes which might be present in consequence of
impurities in the toluene which was used, except to point out that
the same considerations apply to trinitro-m-xylene (TNX) as
apply to 2,4-dinitrotoluene—a little does no real harm—while the
nitre derivatives of o- and p-xylene are likely to form oils and
are extremely undesirable. In m-nitrotoluene, the nitro group
inhibits further substitution, the methyl group promotes it, the
two groups disagree in respect to the positions which they activate,
but substitution takes place under the orienting influence
(if the methyl group.
, r> N o - ,-
/3-TNT or 2,3,4-trinitrotoluene (m.p. 112°) is the principal
product of the nitration of m-nitrotoluene; y-TNT or 2,4,5trinitrotoluene
(m.p. 104°) is present in smaller amount; and of
?-TNT or 2,3,6-trinitrotoluene (m.p. 79.5°), the formation of