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588 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

also yields nitroform. Hantzsch and Rinckenberger [50] obtained its ammonium

salt by treating tetranitromethane with aqueous ammonia. This method is mostly

applied for the laboratory preparation of nitroform.

Nitroform can exist in two forms [50]: a nitro form (I) and an aci-form (II)

I II

The colourless form (I) exists in solution acidified with hydrochloric or sulph-

uric acid and also in anhydrous benzene, carbon disulphide and ether. Aqueous

and basic solutions are intensely yellow due to the presence of the form II. Solu-

tions in acetic acid are slightly yellow, which would indicate that the two forms exist

in equilibrium in this medium.

Most salts derive from the aci-form (II). However, the silver and mercuric salts

exist in two forms: colourless and yellow. This would indicate that two forms of

these salts - nitro and aci - can exist.

The explosive properties of nitroform have been proved by Shishkov [48].

Nitroform salts also exhibit explosive character.

Trinitromethane reacts with formaldehyde forming trinitroethyl alcohol (Hurd

and Starke [51]) :

CH(NO 2 ) 3 + CH 2 O -> C(NO 2 ) 3 .CH 2 OH (19)

The reaction is highly exothermic. It should be controlled, so as to prevent its

temperature exceeding 70-80°C. Trinitroethyl alcohol is an unstable, crystalline

compound, melting at 36-37°C (Ficheroulle and Gay-Lussac [52]). Its initiation

temperature is about 120°C.

Trinitroethyl alcohol may be esterified with acetic anhydride to the acetate,

which is much more stable than the alcohol itself and at temperatures of 120-140°C

shows no distinct signs of decomposition. Both alcohol and acetate are very good

solvents for nitrocellulose.

TETRANITROMETHANE

Tetranitromethane was first obtained by Shishkov [48] in 1857, but it was only

during the World War II that the Germans experimented with it on a large scale,

using mixtures of tetranitromethane with various combustible materials as rocket

propellants.

PHYSICAL PROPERTIES

Tetranitromethane, C(NO 2 ) 4 , is a heavy oily liquid (sp. gr. 1.65), which solidi-

fies at +3°C and boils at 126°C without decomposition. It is insoluble in water,
but it dissolves easily in alcohol and benzene. It is a volatile substance with a charac-

teristic smell, reminiscent of nitrogen oxides.

Menzies [53], later Nicholson [54] and Edwards [551 measured the vapour pres-
sures of tetranitromethane and obtained similar values.