The Chemistry of Powder and Explosives - Sciencemadness Dot Org

DINITROGLYCERIN 217
Both of the dinitroglycerins on treatment with 30% sodium
hydroxide solution at room temperature yield nitroglycide, and
this substance on boiling with water gives a-mononitroglycerin,
a series of reactions which demonstrates the identity of the lastnamed
compound.
Dinitroglycerin is a feeble acid and gives a wine-red color with
blue litmus, but none of its salts appear to have been isolated
and characterized. It does not decompose carbonates, but dissolves
in caustic alkali solutions more readily than in water. One
hundred parts of water alone dissolves about 8 parts at 15° and
about 10 parts at 50°.
Dinitroglycerin gelatinizes collodion nitrocotton rapidly at
ordinary temperature. The gel is sticky, less elastic, and more
easily deformed than a nitroglycerin gel. Unlike the latter it is
hygroscopic, and becomes softer and greasier from the absorption
of moisture from the air. Water dissolves out the dinitroglycerin
and leaves the nitrocellulose as a tough, stiff mass.
Dinitroglycerin has about the same sensitivity to initiation as
nitroglycerin, only slightly less sensiti\-ity to shock, and offers
no marked advantages from the point of view of safety. It shows
a greater stability in the heat test, and a small amount can be
evaporated by heat without explosion or deflagration. It gives
off red fumes above 150°, and at 170° decomposes rapidly with
volatilization and some deflagration, or in larger quantities
shows a tendency to explode.
Naoum 33 reports that a 10-gram sample of dinitroglycerin in
the Trauzl test with water tamping gave a net expansion of
about 500 cc, or 83.3% as much as the expansion (600 cc.) produced
by 10 grams of nitroglycerin under the same conditions.
He points out that the ratio here is almost the same as the ratio
between the heats of explosion, and that in this case the Trauzl
test has supplied a fairly accurate measure of the relative energy
contents of the two explosives. In the small lead block test the
effect of the greater brisance and higher velocity of detonation
of nitroglycerin becomes apparent; 100 grams of dinitroglycerin
gave a compression of 21 mm. while the same amount of nitroglycerin
gave one of 30 mm.
32 Op. cit., p. 170.