Environmental Engineering Reference
In-Depth Information
Table 7.45 Parameters for
high purity H
2
O
2
Parameters
Values
Relative density at 20
°
C
1.39
viscosity at 18
°
C (cps)
11.62
vapor pressure at 30
°
C (mmHg)
5
solidifying point (
°
C)
11.1
−
Boiling point (
°
C)
175
Enthalpy of formation (
D
H
f
)
-
Liquid (kJ mol
−
1
)
188.95
Gas (kJ mol
−
1
)
139.29
Capacity (0
18.5
°
C) cal/g
°
C
0.58
-
vaporization heat (J/g)
138.72
Surface tension at 18
°
C (dyn/cm)
75.53
Conductivity at 25
°
C
-
10
−
6
chemically pure
2
×
10
×
10
−
6
Industrial grade
Refractivity at 20
°
C
1.398
Residue
0.005 %
Hydrogen peroxide can be used as a monopropellant by taking advantage of the
decomposition reaction triggered by catalysts. 80
85 % concentration hydrogen
peroxide can be used not only as liquid explosives, but also in the launch of
unmanned aerial vehicle (UAV). Oxidizers and fuels from respective tanks are
injected into the combustion chamber for reaction that generates thrust to engine for
the launch of rocket and other aircraft. These applications are based on the fol-
lowing reaction where hydrogen peroxide decomposes to form water and oxygen.
-
1
2
O
2
þ
H
2
O
2
þ
H
2
O
þ
98
:
116 kJ
=
mol 2886
ð
:
96 J
=
g
Þ
Adding calcium permanganate and sodium permanganate aqueous solutions to
hydrogen peroxide can trigger its decomposition. Potassium permanganate,
in
contrast, is not a right choice as its solubility in water is so weak that not suf
cient
amounts of MnO
4
−
are present to induce the reaction.
The working principle for the rocket booster is similar to that of the engine. The
former allows 280 L H
2
O
2
and 20 L solutions of permanganates to be loaded.
Replacing these propellants with hydrazine and nitric ether gives rise to comparable
performance. Shown in Table
7.46
is the thermochemical energy in the H
2
O
2
monopropellant.
According to Table
7.46
, for H
2
O
2
its heat of decomposition is much larger than
the heat of vaporization and hence the steam generated stays in high temperature
that effectively give high pressures. It means that H
2
O
2
can serve as both propellant
and liquid explosive. In fact, the speci
c impulse for H
2
O
2
propellant is found not
larger than 232 s.
