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NITRO DERIVATIVES OF HALOGENOBENZENES^469

2,4,6-TRINITRO DERlVATlVE OF 1,3,5-TRICHLOROBENZENE

1,3,5-Trichloro-2,4,6-trinitrobenzene (m. p. 187°C) can be prepared by the

nitration of 1,3,5-trichlorobenzene with anhydrous nitric acid and oleum (Jackson

and Wing [42]). However, according to van Ryn [43] the yield is poor.

Alone, the compound is of no interest as an explosive, for 1,3,5-trichlorobenzene

is too expensive as a starting material. It is prepared by the chlorination of aniline

followed by diazotization and reduction with alcohol. Nevertheless it may be used

for the preparation of explosives with certain specially valuable properties, for

example, an initiating substance - trinitrotriazidobenzene - (Vol. III) or for the

very powerful high explosive - trinitrotrimethylnitroaminobenzene (Vol. III).

It was used in Germany as an insecticide.

Manufacture of 1,3,5-trichloro-2,4,6trinitrobenzene. The I. G. Griesheim Works

applied the following process for the manufacture of the above product.

The reactor is charged with 980 kg of 30% oleum to which 100 kg of solid

trichlorobenzene is added during the course of one hour. The whole is heated to

100°C for another hour and kept at this temperature for 2-3 hr longer with

constant stirring. Towards the end of this operation sulphonation takes place. The

reaction may be considered complete when a sample of the mixture taken from

the nitrator dissolves completely in water.

After cooling the reactor contents to 50°C 300 kg of 99% nitric acid are added

during about 4 hr. While this is being done the temperature rises to 100°C. After

all the nitric acid has been added, the mixture is stirred for another 10-14 hr, then

during the course of a further 8 hr the temperature is gradually raised to 140-145°C.

As too rapid a rise of temperature would involve the risk of decomposition, if this

occurs the nitrator contents should be drained off into a safety tank. After a tem-

perature of 140-145°C has been attained, the mixture in the nitrator is stirred

at this temperature for further 45 hr. At this stage of the process the product of

the reaction crystallizes. Then the nitrator contents are cooled down to 20°C and

transferred by compressed air to the filter. The filtered product is transferred to a

washing tank, where it is washed by mixing with cold water, followed by decanta-

tion, several times until free from acid (Congo paper test).

The spent acid contains 13% of HNO 3 and H 2 SO 4 + SO 3 equivalent to 90% H 2 SO 4.

The washed, acid-free product is filtered off on a vacuum filter and dried

under reduced pressure at 100°C. In this way 125 kg of the product melting at 189
-190°C are obtained, which corresponds to 72% of the theoretical yield.