Tetryl


Tetryl, or 2,4,6-trinitrophenylmethylnitramine
[20] , is a sensitive explosive compound used to make detonators and explosive booster charges. It is an odorless yellow crystalline solid that is not found naturally in the environment. Under certain conditions, tetryl can exist as dust in air. It is slightly soluble in water and in other liquids.

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Properties:
IUPAC NAME: 2,4,6-Trinitrophenyl-N-methylnitramine
OTHER NAME: nitramine, tetralite
MOLECULAR FORMULA: C7H5N5O5
MOLAR MASS: 287.15 g/mol
SHOCK SENSITIVITY: insensitive
FRICTION SENSITIVITY: insensitive
EXPLOSIVE VELOCITY: 7,570 m/s

Tetryl was first described by Michler and Meyer in 1879, and was studied soon thereafter by van Romburgh and by Mertens. Van Romburgh proved its structure by synthesizing it from picryl chloride and potassium methylnitramine.

Tetryl was used mainly during World Wars I and II and later conflicts. Tetryl is usually used on its own, though can sometimes be found in compositions such as tetrytol. Tetryl is no longer manufactured or used in the United States, but can still be found in legacy munitions such as the M14 anti-personnel landmine.

In the early literature of the subject, and to some extent at present, the substance is wrongly designated as tetranitromethylaniline. It results from the nitration of monomethyl- and of dimethylaniline, and is prepared industrial1y by the nitration of the latter. The course of the reactions is first the introduction of two nitro groups in the nucleus, then the removal of one of the methyl groups by oxidation, then the introduction of a third nitro group in the nucleus, and final1y the replacement of the amino hydrogen by a nitro group.

All the above-indicated intermediates have been isolated from the reaction. The last step is interesting because it is a reversible nitration. If tetryl is dissolved in concentrated sulfuric acid and allowed to stand, the nitro group on the nitrogen is replaced by hydrogen, and nitric acid and trinitromethylanilžne (methylpicramide) are formed. Tetryl accordingly gives up this nitro group, and only this one, in the nitrometer. In the industrial preparation of tetryl, the usual method is to dissolve the dimethylaniline in concentrated sulfuric acid and then to carry out all the reactions in one stage. The crude tetryl contains impurities which must be removed by boiling the finely comminuted substance in water, and by dissolving the crude material in benzene and filtering for the removal of insoluble materials. For the industrial crystallization of tetryl, either acetone or benzene is commonly used.
At ordinary temperatures tetryl appears to be perfect1y stable. Current methods of purification insure the absence of occluded acids. It is more powerful and more brisant than TNT and picric acid, though distinct1y more sensitive to shock, and is probably the best of all the common explosives for use in boosters and reinforced detonators.