Environmental Engineering Reference
In-Depth Information
Fig. 5.1
Schematic diagram
of continuous nitration for
methyl nitrate
80
C. The methanol mixture and nitric acid are added dropwise with a rate of
80
-
160 drop/min. Layering would be observed in the receiver. The temperature of
the distillation head is decreased to 65
85
°
-
°
C and the reaction temperature is decreased
to 95
C. After dropwise addition, the temperature will be kept for another 30 min
to ensure the complete installation of products in the vessel. The product at the
bottom of the receiver is methyl nitrate.
The acidic crude product would be washed by water to pH 7. Sodium carbonate
solution would be then used to continuously wash the product to pH 7.2
°
7.5. The
-
final crude methyl nitrate product with yield 98.7 % would be stored with the
desiccant of magnesium sulfate. The production process of methyl nitrate is shown
in Fig.
5.2
.
In the process, the main steps include nitration, distillation, washing, drying,
recti
cation, and waste treatment. The crude methyl nitrate is recti
ed to obtain
pure methyl nitrate at the boiling range of 64.5
65
°
C. The IR spectrum of pure
-
methyl nitrate is shown in Fig.
5.3
.
The bands at 1,625 and 1,282 cm
−
1
can be assigned to the stretching vibration of
ONO
2
group of methyl nitrate, as shown in Fig.
5.3
, and a series of strong and
broad bands are shown at 855 and 760 cm
−
1
.
In summary, by this preparation method, 100 units of methanol can be converted
to 234.98 units of methyl nitrates after recti
-
cation and collection at 64.5
-
66
°
C.
The theoretical yield is 97.5 %.
