Environmental Engineering Reference
In-Depth Information
Table 5.42
Crystallization
heat of nitroglycerine with
different phases
Phase
Crystallization heat
(J/g)
Stable form
138.91
Unstable form
21.76
Conversion from unstable form to
stable form
117.20
60
40
20
20
60
100
140
180
220
260
300
Time (min)
Fig. 5.14
The catalytic decomposition of nitroglycerine by 5 % nitric acid at 42
°
C[
3
]
The other products, such as N
2
, NO, CO, and CO
2
, will not
uence the
decomposition rate of nitroglycerine. Nitroglycerine will be decomposed in 30 h if
the content of water in feedstock is 0.01 % and in 2 h if the content of water is up to
1.5 %.
The result of thermogravimetric analysis of nitroglycerine at 90
in
fl
C dem-
onstrates that the volatile products of decomposition can be removed by CO
2
. The
pH value of nitroglycerine will be increased with heating time. The pH values of
water-extracted materials of nitroglycerine at 110
135
°
-
°
C in different heating time are
listed in Table
5.43
.
The relationship of pH of nitroglycerine and time is shown in Fig.
5.15
.
The mechanism of nitroglycerine decomposition at 135
C is obviously different
from that at low temperatures. The color of samples will be changed to be red
because they adsorb the decomposition products. At heating temperature of 145
°
C,
the decomposition will become vigorous with a release of gases of nitrogen oxides.
At heating temperature of 165
°
°
C, nitroglycerine will be more vigorously decom-
posed to nitric acid, which will be distilled off with nitroglycerine. The residue
contains glycerine, nitrate esters, dinitrate esters, and trace liquid impurities, which
are difficult to be determined. At heating temperature of 180
-
185
°
C, nitroglycerine
will become very sticky. The explosion behavior of nitroglycerine will be termi-
nated at 215
C. Those observations indicate that nitroglycerine is not as safe
and insensitive as people used to believe.
Nitroglycerine will be exploded at extreme high temperature. If nitroglycerine is
dripped on a preheated metal plate of 215
218
°
-
C, a detonation will be happened and
the metal plate will be severely deformed. When the metal plate is preheated to over
420
250
°
-
