The Chemistry of Powder and Explosives - Sciencemadness Dot Org

280 NITRIC ESTERS
is destroyed within a few minutes by boiling with a 2.5% solution
of caustic soda, PETN requires several hours for its complete
decomposition. Ammonium sulfide solution attacks PETN
slowly at 50°, and a boiling solution of ferrous chloride decomposes
it fairly rapidly. It does not reduce Fehling's solution even
on boiling, and differs in this respect from erythrite tetranitrate.
PETN does not take fire from the spit of a fuse. If a small
quantity is submitted to the action of a flame, it melts and takes
fire and burns quietly with a slightly luminous flame without
smoke. Above 100° it begins to show appreciable volatility, and
at 140-145°, or at temperatures slightly above its melting point,
it shows red fumes within half an hour. It inflames spontaneously
at about 210°. It is relatively insensitive to friction but makes a
loud crackling when rubbed in a rough porcelain mortar. It may
be exploded readily by pounding with a carpenter's hammer on
a concrete floor. In the drop test it is detonated by a 20-cm. drop
of a 2-kilogram weight, sometimes by a drop of 10 or 15 cm.
Naoum 110 reports that 10 grams of PETN in the Trauzl test
with sand tamping gave a net expansion of about 500 cc, with
water tamping one of 560 cc. The same investigator 111 found a
velocity of detonation of 5330 meters per second for the material,
only slightly compressed, at a density of loading of 0.85 in an
iron pipe 25 mm. in internal diameter. For PETN compressed to
a density of 1.62 Kast 112 found a velocity of detonation of 8000
meters per second.
PETN is extraordinarily sensitive to initiation. It is detonated
by 0.01 gram of lead azide, whereas tetryl requires 0.025 gram of
lead azide for its certain detonation. This sensitivity and its. great
brisance combine to make PETN exceptionally serviceable in
compound detonators.
Under high pressure powdered PETN agglomerates to a mass
which has the appearance of porcelain, but which, when broken
up into grains, is a very powerful smokeless powder functioning
satisfactorily with the primers which are commonly used in small
arms ammunition. The powder is hot and unduly erosive, but
cooler powders have been prepared by incorporating and compressing
PETN in binary or in ternary mixtures with TNT,
no Ibid., p. 246.
in/bid., p. 247.
"2Z. angew, Chem., 36, 74 (1923).