The Chemistry of Powder and Explosives - Sciencemadness Dot Org

206 NITRIC ESTERS
decomposing liquid becomes proportionately greater, and at
about 218°C. nitroglycerm explodes. 15
When nitroglycerin is maintained at a temperature between
145° and 210°C, its decomposition goes on rapidly,
accompanied by much volatilization, and under these conditions
nitroglycerin may be readily distilled. The distillate
consists of nitroglycerin, nitric acid, water, and other decomposition
products. The residue that remains after heating
nitroglycerin under such conditions for some time probably
consists mainly of glycerin, with small amounts of dinitroglycerin,
mononitroglycerin, and other decomposition products.
These substances are far less explosive than ordinary
nitroglycerin, and accordingly by heating nitroglycerin
slowly it can be caused to "boil" away until the residue
consists of products that are practically non-explosive. In a
number of experiments nitroglycerin was thus heated, and
a copious residue was obtained. By carefully raising the
temperature this residue could be made to char without
explosion.
Belyaev and Yuzefovich 16 heated nitroglycerin and other explosives
in vacuum; and procured the results summarized in the
following table. The fact that ignition temperatures are fairly
Methyl nitrate
Glycol dinitrate
TNT
Picric acid
TNB
PETN
Nitroglycerin
BP.
(2 mm)
EXPERI-
MENTAL,
°C.
,
70
190
195
175
160
125
BP.
(50 mm )
EXPERI-
MENTAL,
°C.
5
125
245-250
255
250
180
180
BJ.
(760 mm.)
MOST
PROBABLE
VALUE,
°C.
66
197 ±3
300 ± 10
325 ± 10
315 ± 10
200 ±10
245 ±5
IGNITION
TEMPER-
ATURE, °c
195-200
295-300
300-310
215
200
close to probable boiling points indicates that high concentrations
of vapor exist at the moment when the substances ignite. The
authors point out that TNT, PETN, and picric acid neither
detonate nor burn in vacuum and suggest that this is probably
15 Munroe had found the "firing temperature" of nitroglycerin to be 203
to 205°, J. Am. Chem. Soc, 12, 57 (1890).
18 Cow»p. rend. acad. sci. UJ5.S.R., 27, 133 (1940).