Environmental Engineering Reference
In-Depth Information
Table 5.41
Dipole moment
of nitroglycerine
Solution
Dipole moment
(Debye)
Pure nitroglycerine
3.82
Nitroglycerine in hexane
2.56
Nitroglycerine in carbon
tetrachloride
2.88
Nitroglycerine in benzene
3.16
Fig. 5.13
Infrared spectrum
of nitroglycerine
(3) Thermal properties
(1) Speci
c heat and crystallization heat of nitroglycerine
The speci
c heat of nitroglycerine is 1.49 J/g. The speci
c heat of its crystal
(stable form) is 0.315 cal/g. The speci
c heat of liquid nitroglycerine is 1.318 J/g.
The crystallization heat (freezing) of nitroglycerine is listed in Table
5.42
.
(2) Combustion heat and formation heat of nitroglycerine
The combustion heat
ʔ
H of nitroglycerine in constant volume is 1541.39 kJ,
equal to 6791 J/g. The formation heat
−ʔ
H
f
is 356.9 kJ (1564.82 J/g). The nitration
heat of glycerine to nitroglycerine in industry is 502.08
711.28 J/g.
-
(4) Stability of nitroglycerine
Nitroglycerine will be decomposed in 3
C to produce acidic
substances. On the sixth day, nitric acid should be observed. If the volatile products
were removed quickly in the decomposition process, nitroglycerine would be
decomposed very slowly.
In an open system, it is no risk for the decomposition of a small amount of
nitroglycerine. In a closed space, NO
x
produced in the decomposition process will
play a part of catalysis. Meanwhile, the gas products will increase reaction pressure
gradually and catalytically accelerate the reaction. The chain reaction will impel
nitroglycerine to be decomposed more quickly and, eventually, cause an explosion.
The mixture of 0.3 g nitroglycerine and 5 % nitric acid in a closed glass tube at
4 days at 75
°
-
42
C for 6 h will explode. The plot of the decomposition temperature of nitro-
glycerine catalyzed by nitric acid versus time is shown in Fig.
5.14
.
The decomposition of nitroglycerine is mainly caused by the dilute acid formed
through NO
2
and water. The dilute acid will catalytically decompose nitroglycerine.
°
