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58 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

Lauer and Oda [20] assumed the existence of nitracidium sulphate (according

to Hantzsch) and suggested that the mechanism of nitration with a nitrating mixture

is as follows:

(16)

A similar nitration mechanism was suggested by Vorozhtsov [21]. He also as-

sumed the formation of an addition product of the hydrocarbon with HNO 3 and

H 2 SO 4 , followed by splitting off H 2 SO 4 and H 2 O.

Usanovich [22] also assumed Hantzsch’s cations to be the nitrating agents

in a mixture of nitric and sulphuric acids. He believed that in the nitration process

the nitracidium cation was attached first accompanied by splitting off water:

(17)

On dilution with water the resulting new cation, C 6 H 5 N(OH) 2 2+, gives nitrobenzene:

C 6 H 5 NO 2 H 2 2+ + 2H 2 O -> C 6 H 5 NO 2 + 2H 3 O+ (18)

In the nitration of aliphatic hydrocarbons the NO 3 - ion reacts:

R.CH 3 + NO 3 - <-> R.CH.NO 2 (OH)- (19)

The anion formed may undergo a hydrolysis process in an acid medium:

R.CH 2 NO 2 (OH)- + H 3 O+ -> R.CH 2 NO 2 + 2H 2 O (20)

In favour of the view, that postulates the formation of an addition product

during the first stage of nitration this fact should be known to all who are prac-

tically engaged in nitration of aromatic hydrocarbons. Immediately before contact-

ing the nitrating acid (HNO 3 or nitric and sulphuric acids mixture), benzene

and toluene give brown coloured products amid nitric acid vapours. On dissolution

in the acid these products decolourize at once. It is quite possible they arc addition

products formed by nitric acid vapours with the hydrocarbon.

The existence of similar addition products must be mentioned here. Steinkopf

and Kühnel [23] observed that benzene reacted with nitryl chloride at room tempera-

ture under pressure to yield 1-chloro-2-nitrocyclohexadiene, which on heating
released a molecule of hydrogen chloride giving nitrobenzene:

(21)