The Chemistry of Powder and Explosives - Sciencemadness Dot Org

202 NITRIC ESTERS
may be identical in all respects with a mixture of strong nitric
and strong sulfuric acids, glycerin is universally nitrated in commercial
practice by means of acid already mixed, and the nitroglycerin
is procured by means of gravity separation of the phases.
One hundred parts by weight of glycerin yield 225 to 235 parts of
nitroglycerin.
One part of glycerin is nitrated with about 6 parts of mixed
acid, made up by the use of oleum and containing about 40.0%
FIGURE 54. Interior of Nitroglycerin Storage House. (Courtesy E. I. du
Pont de Nemours and Company, Inc.)
of nitric acid, 59.5% of sulfuric acid, and 0.5% of water. The
nitration in this country is carried out in cast iron or steel nitrators,
in Europe in nitrators of lead. The glycerin is commonly
added from a cock, controlled by hand, in a stream about the
size of a man's finger, The mixture is stirred by compressed air,
and the temperature is controlled carefully by means of brine
coils, there being usually two thermometers, one in the liquid,
one in the gas phase above it. In Great Britain the temperature
of the nitration mixture is not allowed to rise above 22°C, in
this country generally not above 25°. If the temperature for any
reason gets out of control, or if the workman sees red fumes
through the window in the nitrator, then the charge is dumped