Environmental Engineering Reference
In-Depth Information
Table 1.1 Typical oxidizers of liquid explosives [
1
]
Compounds
M
t
θ
m
/
°
C
θ
b
/
°
C
ρ
(20
°
C)/
OB
×
100
H
f,m
/
kJ mol
−
1
△
gcm
−
3
Condensed nitric
acid (95 %)
63.01
−
4
86
1.5027
63.5
−
173.0
Dinitrogen
tetroxide
92.0
10.2
21
1.49
69.6
9.8 (gas)
−
−
Tetranitromethane
196.04
14.2
126
1.638
49.0
36.8
Hydrogen peroxide
34.02
−
0.41
150
1.39
47.1
−
188.8
Hydrazine nitrate
95.1
70.7
1.64
8.6
250.0
−
Hydrazine perchlorate
132.5
144
1.83
24.1
176.4
−
Urea perchlorate
160.5
83
1.623
9.9
TNEOF
552.2
128
1.80
10
−
630.7
TNEOC
732.4
161
1.84
13
500.9
−
β
type. The former is usually used in explosives. Its solubility is small in alcohols but
large in water and hydrazine. It has strong hygroscopicity, only slightly lower than
ammonium nitrate.
Hydrazine nitrate has a good thermal stability. Its weight loss rate at 100
There are two crystalline types for hydrazine nitrate, stable
α
type and unstable
°
Cis
slower than that of ammonium nitrate [
20
]. Its explosion point is 307
C (50 %
detonation) and explosion heat is about 3.829 MJ/kg. Because of no carbon ele-
ments, the detonation products are not solid and their average molecular weight is
small.
Hydrazine nitrate was synthesized by neutralization reaction between nitric acid
and hydrazine. In early years, anhydrous hydrazine was used to dissolve into
methanol. The solution was cooled down to approximately
−
20
°
C, and then slowly
added to diluted nitric acid (70 %) with temperature of
°
20
°
C till pH of 5.5. The
−
temperature should keep under 0
C in the whole reaction process. The precipitates
of hydrazine nitrate were successively treated by
°
filtration, recrystallization, and
drying to obtain
final products.
The method was improved later to reduce the production cost. In the new
synthesis process, hydrazine hydrate with concentration of 80 % and nitric acid of
80 % were adopted as raw materials and ethanol (95 %) was used as a inert medium
and precipitant. At the condition of the precipitation temperature at 0
C and time
over 30 min, the precipitation ratio can be up to 90 % with the product purity of up
to 99 %.
(2) Dinitrogen tetroxide
Dinitrogen tetroxide (N
2
O
4
) forms an equilibrium mixture with nitrogen dioxide.
The molecule is relatively stable because of its symmetric structure. It has strong
oxidizability, high toxicity, and strong corrosivity. It is usually used as an oxidizer
in propellants. Under standard atmospheric pressure, its boiling point is 21.2
°
°
C, its
C) is 1.446 g/cm
3
. The appearance
