Environmental Engineering Reference
In-Depth Information
Na
2
SO
3
belong to salts of a strong acid and a weak base, which can control and
buffer the concentration of [OH] through hydrolysis reaction:
2H
2
O = 2Na
þ
þ
2OH
þ
Na
2
CO
3
þ
H
2
CO
3
2H
2
O = 2Na
þ
þ
2OH
þ
Na
2
SO
3
þ
H
2
SO
3
Because of Na
2
CO
3
>Na
2
SO
3
, and H
2
SO
3
obtained in Na
2
SO
3
hydrolysis can
be further ionized:
H
2
SO
3
=2H
þ
+SO
2
3
The ionization constant of H
2
SO
3
is larger than that of H
2
CO
3
, and its ionization
rate is considerably higher than that of H
2
CO
3
.H
+
should neutralize OH
−
in the
solution to form water and reduce the basicity of the solution, and further slow
down the saponi
cation.
The preparation conditions of nitro isobutyl glycerine trinitrate are summarized
below.
(1) Sulfonation: H
2
SO
4
concentration of 100
±
0.5 %, NO
2
C(CH
2
OH)
3
:
H
2
SO
4
= 1:2.75, temperature of 45
±
5
55
±
5
°
C.
-
(2) Composition of nitration mixed acid: 80
±
1.5 % HNO
3
,20
±
1.5 % H
2
SO
4
,
2%H
2
O, and <0.4 % N
2
O.
(3) Ratio of feedstock: sulfate ester: mixed acid = 3.75:2.75 (by weight)
Nitration temperature: 40
±
1
46
±
1
°
C, stop feeding temperature: 45
49
°
C,
-
-
feeding temperature: 51
C.
(4) Separation temperature: 35
°
±
6
°
C, retention time in gravity separation
method of 35
5 min.
(5) Washing and stability treatment: feed ratio in prewashing step (by volume) of
oil/water = 1:8 (20
±
±
5
°
C), agitation pressure of 0.1
-
0.2 kg/cm, feed ratio in water-
washing step (by volume) of oil/water = 1:8 (20
C), concentration of alkali-
washing solution: 2 % Na
2
CO
3
and 6 % Na
2
SO
3
, feed ratio (by volume) of oil/alkali-
washing solution = l:2.8
±
5
°
12.
The theoretical yield based on the reaction equation is 189 %, but the actual
yield is 163.5 %, about 86.5 % of the theoretical yield. The speci
-
3.8, pH in tower #1 of 9
-
10 and in tower #2 of 11
-
cation of nitro
isobutyl glycerine trinitrate is summarized in Table
5.54
.
Table 5.54
Speci
cation of
nitro isobutyl glycerine
trinitrate
Parameter
Value
Appearance
Colorless or light yellow
transparent oily liquid
Abel test at 72
°
C
>25 min
Basicity (Na
2
CO
3
-based)
<0.01 %
Acidity
None
Moisture
N.A.
