urbaf2

368 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

The composition of the nitration products obtained in the separate nitrators

is reflected by the melting points of the products:

Nitrator 315°C Nitrator 955°C

4 35°C^10 63°C

5 50°C^11 69°C

6 45°C^12 72°C

7 41°C^13 76°C

8 35°C^14 77°C

The formation of trinitrotoluene begins in nitrator 5. For 1000 kg of TNT

are used in the process.

470-480 kg of toluene

1090-1160 kg of HNO 3

410-440 kg of H 2 SO 4

German method

During World War II a continuous process for nitrating toluene to TNT devel-

oped by J. Meissner [19] and patented in 1941 was introduced at the Schlebusch

factory in Germany. The nitration unit consisted of 5 nitrators and 4 separators,

as shown in the schematic diagram in Fig. 86. Both the nitrators and the separators

FIG. 86. Diagram of the German continuous nitration of toluene to TNT (CIOS XXIV 4).

are arranged in a cascade so as to enable the liquid to flow down from higher vessels

to lower ones. In this way the nitration mixture can be transferred from the nitra-

tor to the separator, where the nitro compound rises to the surface and flows off

through a drain between the separator to the next nitrator. The waste acid flows

down from the bottom of the separators to storage tanks.

The nitrators are 1.5 m high and 1 m in diameter. The separators are 0.75 m

high and 1.5 m in diameter. Both are fabricated from cast iron.

Recently F. Meissner, Wannschaff and Othmer [20] have published some data

on J. Meissner’s continuous method of preparation of TNT, which is an improve-

ment of an earlier patent of Meissner’s.

The design of the plant is based on the combination of the co-current process

with the counter-current-battery system. The plant consists of three aggregates,

each of them comprising the following stainless steel parts:

(1) tanks for reactants and metering tanks for the continuous supply of nitrating

mixture and hydrocarbon;