Environmental Engineering Reference
In-Depth Information
Table 5.53
Speci
cation of Na
2
SO
3
Item
Value
First class
Second class
Na
2
SO
3
(%)
≥
96
≥
93
Iron (%)
≤
0.02
≤
0.02
Water insoluble (%)
≤
0.03
≤
0.03
Free alkali (%, Na
2
SO
3
-based)
≤
0.6
≤
1.0
Concentrated
sulphuric acid
Fumed
sulphuric acid
Nitro isobutyl
glycerine
Sulfonated
acid
Sulfonation
Nitration
Separation
Washing
Collection
Product
Concentrated
sulphuric acid
Mixed
acid
Waste acid
treatment
Safety
treatment
Concentrated
nitric acid
Fig. 5.22
Preparation process of nitro isobutyl glycerine trinitrate
the second step. The concentration and amount of nitric acid is determined by the
need of NO
2
in later esteri
cation and the conversion of the sulfate ester to nitrate
ester. Meanwhile, the side reactions, such as oxidation and resini
cation, should be
avoided. The yield and quality of the product, as well as the safety issue, are related
to reaction temperature. In the sulfonation process of nitro isobutyl glycerine, the
reaction rate is too slow at low temperature. However, if the temperature is too high,
dehydration condensation would happen. Thus,
the sulfonation temperature is
usually at 45
50
°
C. The nitration temperature in a reaction vessel under agitation is
-
usually at 44
15 min.
Stability treatment of nitro isobutyl glycerine trinitrate is dif
±
1
°
C. The nitration time is about 10
-
cult because of its
sensitivity to bases. The mixture solution of Na
2
CO
3
and Na
2
SO
3
can be used as a
washing solution. A good washing effect can be obtained with relatively few
products of saponi
cation and semi-solid impurities are related
to pH value of the solution after washing. At pH < 7, nitro isobutyl glycerine
trinitrate would not be saponi
cation. The saponi
ed and the washing solution is ivory-white or light
yellow. At pH > 9, the saponi
cation is serious and the washing solution is yellow
and turbid with
fl
flocculent materials on the surface. Therefore, the critical point to
