Chemistry Reference
In-Depth Information
Table 11.2
Effect of phenol stabilizer (10
−
2
% PhOH) on the kinetics of the heterogeneous decom-
position of h/c H
2
O
2
k
S
k
S
(PhOH)
Temperature,
◦
C
F
/
V
,cm
−
1
k
S
,cms
−
1
k
S
(PhOH), cm s
−
1
Material
10
−
7
10
−
8
90.5
H18N10T
1.25
1
.
8
×
8
.
05
×
2.24
10
−
8
10
−
8
81.1
H18N10T
1.25
9
.
5
×
4
.
32
×
2.20
10
−
7
10
−
7
96.2
H18N10T
1.25
2
.
5
×
1
.
11
×
2.25
8
.
3
×
10
−
8
3
.
45
×
10
−
8
83.1
H18N10T
1.25
2.41
10
−
7
10
−
7
98.4
H18N10T
1.25
2
.
5
×
1
.
06
×
2.34
10
−
7
10
−
7
67
NP-2
2.5
4
.
6
×
1
.
88
×
2.44
10
−
7
10
−
7
62.5
NP-2
2.5
3
.
1
×
1
.
34
×
2.31
1
.
7
×
10
−
6
7
.
3
×
10
−
7
79.8
NP-2
2.5
2.39
10
−
6
10
−
6
85.3
NP-2
2.5
2
.
5
×
1
.
10
×
2.26
10
−
6
10
−
6
88
NP-2
4.1
4
.
1
×
1
.
78
×
2.30
pseudo-heterogeneous processes under consideration. The correctness of this sug-
gestion has been shown experimentally, at least for stainless steel and nickel-based
alloy, by using phenol-stabilized h/c H
2
O
2
(see Table 11.2). The introduction of phe-
nol (10
−
2
%) results in a 2.2-2.5-fold decrease in the rate of h/c H
2
O
2
homogeneous
decomposition. The decreases in the rate constants of heterogeneous decomposition
on the stainless steel and nickel-based alloy surfaces are identical within experimen-
tal accuracy.
11.3.3 Thermal Explosion of H
2
O
2
The thermal explosion kinetics and corresponding critical conditions were studied
by the method described in Sect. 10.5.3. In the experiments carried out at
P
∞
=
0.1-1.6 MPa, samples of h/c H
2
O
2
characterized by initial TSI values of 14-30 were
studied.
Since typical thermograms obtained at high pressures (Fig. 11.7) have parts at-
tributed to the stationary process, the corresponding points can be plotted on a
Semenov diagram (Fig. 11.18). The data obtained at various
P
∞
values are in qual-
itative agreement with the
q
(
T
) dependencies given in Figs. 10.2 (theory) and 10.6
(heat evolution during the decomposition of DINA). The congruence of the low-
temperature parts of the heat-evolution curves for low and high pressures is in quan-
titative agreement with the theory.
The congruence of the low-temperature parts at
P
∞
= const for h/c H
2
O
2
de-
composition is explained by the absence of an autocatalytic effect (O
2
does not
influence the decomposition rate). In DINA decomposition (Fig. 10.6), the opposite
situation applies due to the autocatalytic influence of nitrogen oxides. The upper
curve in Fig. 11.18 (at
P
∞
= 1
.
6 MPa) can be very well described by the theoretical
relationship
