The Chemistry of Powder and Explosives - Sciencemadness Dot Org

284 NITRIC ESTERS
At a time when the only practicable methods for the preparation
of nitromethane were the interaction of methyl iodide with silver
nitrite and the Kolbe reaction from chloracetic acid, the explosive
was far too expensive to merit consideration. The present cheap
and large scale production of nitromethane by the vapor-phase
nitration of methane and of ethane has altered the situation profoundly.
Trimethylolnitromethane trinitrate is an explosive which
can now be produced from coke, air, and natural gas. Nitromethane
too has other interest for the manufacturer of explosives.
It may be used as a component of liquid explosives, and it
yields on reduction methylamine which is needed for the preparation
of tetryl.
The crude trimethylolnitromethane from the condensation commonly
contains a small amount of mono- and dimethylolnitromethane
from reactions involving one and two molecules of
formaldehyde respectively. It is recrystallized from water to a
melting point of 150°, and is then nitrated. Stettbacher reports
that the pure substance after many recrystallizations melts at
164-165°. The nitration is carried out either with the same mixed
acid as is used for the nitration of glycerin (40% nitric acid,
60% sulfuric acid) or with very strong nitric acid, specific
gravity 1.52. If the trihydric alcohol has been purified before
nitration, there is but little tendency for the nitrate to form
emulsions during the washing, and the operation is carried out
in the same way as with nitroglycerin. In the laboratory preparation,
the nitric ester is taken up in ether, neutralized with
ammonium carbonate, dried with anhydrous sodium sulfate, and
freed from solvent in a vacuum desiccator.
The explosive is procured as a yellow oil, more viscous than
nitroglycerin, density 1.68 at ordinary temperature. It has but
little tendency to crystallize at low temperatures. A freezing
point of —35° has been reported. It is very readily soluble in
ether and in acetone, readily soluble in alcohol, in benzene, and
in chloroform, and insoluble in ligroin. It is less soluble in water
and less volatile than nitroglycerin. Because it is less volatile, it
is slower to cause headaches, and for the same reason the headaches
are slower to go away. It is distinctly inferior to nitroglycerin
as a gelatinizing agent for collodion nitrocotton. The
nitro group attached directly to an aliphatic carbon atom appears
to have an unfavorable effect on stability, for trimethylol-