urbaf2

414 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

NITRO DERIVATIVES OF ETHYLBENZENE

Ethylbenzene is always present in crude xylene and in solvent-naphtha. Since

the boiling point of ethylbenzene (136°C) is identical with the boiling point of

p- xylene, the two are difficult to separate. It is possible to do so by cooling. as

the freezing point of ethylbenzene is -94.9%.

Fittig and Tollens [27] obtained ethylbenzene by synthesis from chlorobenzene

and ethyl chloride. At first they believed it was xylene (basing their view on its

boiling point). However, the substance did not yield a crystalline product when

nitrated, as in the case of xylene, but an oily one, from which they inferred that

the “ethylphenyl” they had obtained was not xylene.

Beilstein and Kuhlberg [28], by nitrating ethylbenzene with a mixture of nitric

and sulphuric acids at a low temperature obtained two oily products which proved

to be o- and p- nitroethylbenzenes.

Weisweiller [29], and later Schultz and Sander [30] obtained 2,4-dinitroethyl-

benzene and 2,4,6-trinitroethylbenzene:

2,4-Dinitroethylbenzene (b. p. 167.5% at 13 mm Hg, m. p. +4°C) was obtained

by reacting ethylbenzene with a mixture of 2 parts of sulphuric acid (sp. gr. 1.84)

and 1 part of nitric acid (sp. gr. 1.43). After the reaction had subsided the tempera-

ture of the mixture was raised to 125-130°C and kept at this temperature for 10

min.

For the preparation of trinitroethylbenzene (m. p. 37°C) ethylbenzene was

treated with a mixture of nitric acid (sp. gr. 1.525) and 30% oleum, initially at 0°C,

then the temperature was raised to 100°C and maintained there for 15-20 min.

After cooling, the trinitroethylbenzene formed remained in the solution. By pouring

the latter into water, the oily product was separated, which then solidified to form

a crystalline mass.

With naphthalene and aromatic amines (e.g. aniline) trinitroethylbenzene

forms addition compounds.

The explosive power of trinitroethylbenzene is rather low, so the compound itself

is of no value. However, it is one of the chief components of liquid nitro-solvent-

naphtha, and is sometimes used as an ingredient in the preparation of explosive

mixtures.

p- Nitroethylbenzene is obtained as an intermediate in chloramphenicol (chloro-

mycetin) synthesis.