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CHAPTER III

NITRATION AGENTS

AND METHODS MORE RARELY USED

NITRATION with concentrated nitric acid or its mixture with sulphuric acid has already

been described and several examples will be given in those chapters dealing

with the preparation of nitro compounds. Methods more rarely used which have

already been applied in practice or may be in future, are described in this chapter.

They are concerned both with using less common nitrating agents and with

nitrating substances which do not yield products of great practical importance

(at least at present). Such, for example, is the nitration of olefins or acetylenes.

NITRATION OF ALKENES AND ALKYNES WITH

CONCENTRATED NlTRIC ACID

Some instances of the nitration of olefins havea heady been described in deal-

ing with the problem of adding a molecule of nitric acid to a double bond. Besides

adding concentrated HNO 3 to olefins, true nitration of olefins through electro-

philic substitution can take place to yield nitroolefins. As early as in 1839 E. Simon

[1], on cautious nitration of styrenes, obtained “nitrostyrene”, which, according to

Alekseyev [2], proved to be o- nitrostyrene. Lipp [3] in 1913 also found that the

action of nitrous acid on camphene resulted in the formation of ω− nitrocam-

phene, along with addition products. In 1878 Haitinger [4] found that the nitra-

tion of isobutylene with anhydrous nitric acid led to several products, among

which was nitroisobutylene (CH 3 )C 2 =CHNO 2 , in 10% yield.

In 1935, Michael and Carlson [5] reported that with fuming nitric acid tri-

methylethylene gave crystalline 3-nitro-2-methyl-2-butylene in 20% yield:

More recently Petrov and Bulygina [6] investigated in detail the conditions

under which several olefins can be nitrated. They found that good yields could
be obtained with concentrated nitric acid reacted with olefins at ca. 60°C, and

with less concentrated at a slightly higher temperature, i.e. 80-90°C. Nitration

was also possible with 20% nitric acid, containing nitric dioxide when reacted

at 70°C. Probably, according to Titov’s theory (p. 88, 118) nitric dioxide is the

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