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CHAPTER XVI

PICRIC ACID ETHERS

As an explosive the acidic character of picric acid and its readiness to form pic-

rates are serious drawbacks. In an attempt to eliminate these disadvantages the

substitution of the acid hydrogen by an aliphatic or aromatic radical has been sug-

gested. The compounds thus formed would be picric acid ethers. For the substitution

of hydrogen by aromatic radicals the latter were connected with nitro groups.

Maxim [1] and du Pont de Nemours Inc. [2] were the first to suggest the appli-

cation of the methyl ether, trinitroanisole, as an explosive.

During World War I materials of this type were used fairly extensively. However,

it has been proved that some of them can undergo hydrolysis, yielding free picric

acid, thus rendering any further use of such explosives unjustifiable. In addition,

most of the products have strongly toxic properties. Hence during World War II

compounds of this type were used only on a small scale.

During the 1914-1918 War trinitroanisole was manufactured in Germany under

the names of Nitrolit, Trinol and An. It was used alone or in admixture with

ammonium nitrate, hexyl, or hexanitrodiphenyl sulphide, for filling high explosive

shells and for submarine and land mines. Eventually it had to take the place of TNT.

In France trinitroanisole was made use of only on the semi-commercial scale,

in mixtures with picric acid or with ammonium or sodium nitrate for filling bombs.

During World War II trinitroanisole was manufactured in Japan for tiling armour

piercing shells.

Trinitroanisole was first obtained by Cahours [2a] by the direct nitration of anisole.

The reaction proceeds very vigorously, as the presence of a methoxy group greatly

facilitates the introduction of nitro groups and some highly coloured by-products

are formed [20]. For this reason it is preferable to prepare trinitroanisole via chlo-

rodinitrobenzene (p. 547).

Similarly trinitrophenetole was first obtained by the direct nitration of phenetole,

but at present this method is not used, chlorodinitrobenzene being a starting material.

Trinitrophenetole is less important then trinitroanisole. Its manufacture never

developed beyond the semi-commercial scale. Similarly other picric acid ethers,

as for example nitro derivatives of phenyl ether, have not found any practical

use.

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