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390 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

Gornall and R. Robinson [28] suggested reducing sodium dinitrotoluene sulphate

(e.g. the sodium salt of 2,4-dinitrotoluene-3-sulphonic acid) to yield m- toluene-

diamine-3-sulphonic acid which could serve as an intermediate for obtaining azo

dyes. Oxidation of sodium 2,4-dinitrotoluene-3-sulphonic acid with potassium

permanganate in alkaline medium gave 2,4-dinitro-3-sulphobenzoic acid, also

an intermediate for azo dyes.

WASTE WATERS

The problem of the neutralization of waste water from the manufacture of TNT,

and the possibility of utilizing the dinitrotoluenesulphonic acids present in them

acquired a considerable importance during World War II, owing to the enormous

output of TNT. In Germany alone the production of TNT was over 20,000 tons a

month, whereas during the World War I it averaged merely 3000 tons a month.

Such a high output involved the use of tremendous quantities of water. Accord-

ing to Kratz [29], for an production of TNT of 4000 tons monthly, 40,000 m^3 of wa-

ter were used daily. Most of this was used for cooling, while the quantity of waste

water containing nitro compounds and acids amounted to 5000-6000 m^3. Kratz

believed this consumption of water to be abnormally high, and caused by hasty

production.

Kratz has classified the “acid” waters according to their origin as follows

(Table 87):

Origin of water

Process water

Condensed water

from concentration of

sulphuric acid

Wash water

Output

m^3 /hr

50

100

80

TABLE 81

Colour and appearance Acid content

brick-red 4 g/l. H 2 SO 4

turbid 2 g/l. HNO 3

almost Colourless, clear 2 g/l. H 2 SO 4

0.3 g/l. SO 2

from light to dark brown 5 g/l. H 2 SO 4

from clear to turbid, 2g/l. HNO 3

with suspension (changeable)

Colour after

purification

with lime milk

dark red

pale pink

dark red

Channels for discharging waste water should be open gutters or loosely closed
troughs. The channels should be built of acid resistant bricks, joined by asplit

(phenolic resin).

The removal of dinitrotoluenesulphonic acids from waste waters prevents

a difficult problem since due to their high solubility they are difficult: to absorb

on carbon or on anion exchangers, or to extract with dibutyl phthalate.