The Chemistry of Powder and Explosives - Sciencemadness Dot Org

NITROGLYCERIN 199
than half its own weight of moisture from the air, and does not
evaporate. Glycerin will solidify in a freezing mixture, and when
iincc frozen melts again at about 17°. It boils at atmospheric
pressure at 290° with slight decomposition, and is best purified by
distillation in vacuum. Its specific gravity is 1.265 at 15°. Perfectly
pure and colorless glycerin yields a water-white nitroglycerin.
Dynamite glycerin is a distilled product of high purity,
density 1.262 or higher, and contains at least 99% of glycerin
and less than 1% of water. It varies in color from pale yellow to
dark brown, generally has a faint odor resembling that of burnt
sugar, and yields a nitroglyccrin of a pale yellow or pale brown
color. The explosives makers consider a test nitration on a laboratory
scale to be the surest way of estimating the quality of a
sample of dynamite glycerin.
Small amounts of glycerin arc produced during an ordinary
alcoholic fermentation, but the quantity is greatly increased if a
considerable amount of sodium sulfite is present. A commercial
process based upon this principle was developed and used in
Germany during the first World War, when the supply of glycerin
from fats was insufficient to fill the needs of the explosives manufacturers,
and similar processes have been used to some extent
elsewhere and since that time. At the beginning of the second
World War an effort was made to increase the production of
whale oil for the manufacture of glycerin. Modern methods—
harpoons shot from guns, fast Diesel-propelled steel ships—resulted
immediately in a tremendous slaughter of whales, and
whale oil again has become difficult to procure. Recent advances
in synthetic chemistry make it probable that glycerin in the
future will be prepared in large quantity from petroleum.
Cracking gas, which is produced when heavy petroleum is
cracked to produce gasoline, consists in large part of olefins, particularly
ethylcne and propylcnc, and is being used more and
more for the manufacture of such materials as glycol and glycerin,
glycol dinitratc and nitroglycerin, mustard gas, ethanolamine
and pcntryl. The olefins under ordinary conditions combine
with two atoms of chlorine, adding them readily to the unsaturated
linkage, and thereafter react with chlorine, no further. It
has been found that chlorine does' not add tu hot propylcnc in the
gas phase, but substitutes instead, one of the hydrogen atoms
of the methyl group being replaced and allyl chloride being