Both trinitroanisol and trinitrophenetol were found to be as satisfactory as compressed TNT for use as a booster charge in 75-mm. shells loaded with schneiderite.

Trinitroaniline (picramide)

2,4,6-Trinitroaniline, orange-red crystals from alcohol, m.p. 186°, has but little interest as an explosive for the reason that other more powerful and more valuable explosives may be prepared from the same raw materials. It may be prepared by nitrating aniline in glacial acetic acid solution or by the use of mixed nitric-sulfuric acid in which no large excess of sulfuric acid is present. The presence of nitrous acid must be avoided, as this attacks the amino group, replaces it by hydroxyl, and results in the formation of picric acid. The nitration of aniline in the presence of a large amount of concentrated sulfuric acid yields m-nitroaniline and later the nitro compounds which are derived from it.

Tetranitroaniline (TNA)

2,3,4,6-Tetranitroaniline, discovered by Flurscheim, has interesting explosive properties but is such a reactive chemical substance that, when all things are considered, it is unsuitable for use. It was used to some, extent during the first World War and was studied very thoroughly at that time.

Flurscheim prepared TNA by a one-stage nitration of m-nitroaniline sulfate, that substance being procured by the reduction of m-dinitrobenzene with sodium polysulfide. The nitra-' tion proceeds smoothly, and the entering groups take the positions indicated by the strongly ortho-para orienting amino group. The yield is about 120 per cent of the weight of the m-nitro-aniline. m

Pure TNA, yellowish-brown or greenish-brown crystals from

NO, acetone, melts with decomposition at about 210° and deflagrates at about 226°! It is soluble in glacial acetic acid (1 part in 24 at boiling temperature), readily in acetone (1 in 6 at boiling temperature), and sparingly in benzene, ligroin, and chloroform. If a small amount of water is added to an acetone solution of TNA and the liquid is refluxed, the nitro group in the 3-position, having other nitro groups ortho and para to it, is replaced rapidly by hydroxyl. The resulting trinitroaminophenol, m.p. 176°, is capable of attacking metals to form dangerous explosive salts which are similar to the picrates. If TNA is boiled with aqueous sodium carbonate or bicarbonate both the amino group and the nitro group in the 3-position are hydrolyzed, and trinitro-resorcinol is formed.

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