3. Nitration:
Nitration is done in three following steps to
obtain TNT(Tri-Nitro-Toluene).
First stage nitration:
This nitration is done by treating
toluene with N2O5 in the presence of DCM (Di-
chloro-methane).
3
5. Conditions:
Temperature should be -30 (mixing temp)
-50oC(Reactor exiting temp).
Residence time 15 to 20 min.
At such conditions we obtain 54.2% ortho
44.3% para and 1.5% of meta isomer.
Meta-isomers can be further reduce (to about
if conditions are more precise i.e -40oC mixing
temperature & -60oC reactor exiting temperature.
5
6. Extraction of MNT
Neutralization step:
After 1st stage nitration, the product is neutralized with
aqueous sodium bicarbonate (NaHCO3) and the
layer recovered.
Concentrating Unit:
After the neutralization process any other amount of
remaining acid or water is removed by using wiped
evaporator.
6
7. Second Stage Nitration:
It is done by treating MNT (Mono-Nitro-
toluene) with HNO3 (Nitric Acid) .
Yield is up to 90%.
7
8. Addition of DCM:
Act as a heat sink for removal of heat.
Secondly to slow down the reaction and therefore control
the exotherm.
Conditions:
6oC to 30oC temperature.
Reaction time 5 min.
Residence time up to 10 min.
8
9. Extraction of DNT
Measured amount of DCM and water is added to
induce phase separation.
The layer is separated and DNT is isolated from
each layer.
9
10. Waste acids are recovered.
Recovery of DCM by cryogenic condensation.
After this DNT is introduced in Third stage
reaction chamber.
10
12. Conditions:
Temperature should be 50oC to 70oC.
Reaction time 6.5 hr.
Yield obtained is about 85%
Kinetics:
Kinetics of this reaction is relatively slow, that’s why
we have to shift this process to batch process.
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13. Extracting of TNT:
Addition of DCM will extract most of the TNT
the acid.
Two layers are formed with around 75% of the
in the organic layer.
Dilution with water and addition of DCM to the
acid layer recovered the majority of the
TNT.
13
14. Neutralization:
It is neutralized by adding NaHCO3.
After neutralization DCM is removed giving solid
product of TNT
Washing:
It is washed with cold water.
14
15. Drying:
Drying in a vacuum oven at 50oC
overnight
TNT as a yellow/white solid (88%).
A purity of 99%.
15
16. Advantages:
Better Yield.
Lowest possible formation of meta isomers.
Disadvantages:
Expensive raw materials (N2O5 AND DCM).
Time consuming.
16
17. Traditional
Method
Advance
Method
Raw Materials are cheap and easily
available
Raw Materials are expensive
Production of NOx & SOx No Harmful gases produced
Yield is about 75-80% Yield is about 88-95%
14-15% Meta isomer production >2% meta isomer production
Red water production during washing No harmful liquid production during
washing
Comparison between traditional and advance method 17