The Chemistry of Powder and Explosives - Sciencemadness Dot Org

382 NITROAMINES AND RELATED SUBSTANCES
(about 4 liters), and allowed to crystallize by standing over night
Yield 300-310 grams, about 90% of the theory
The rapid cooling of a solution of a-nitroguanidme produces
small needles, which dry out to a fluffy mass but which are still
too coarse to be incorporated properly in colloided powder. An
FIGURE 89. a-Nitroguanidine (25X). Small crystals from the rapid cooling
of a hot aqueous solution
extremely fine powder may be procured by the rapid cooling of
a mist or spray of hot nitroguanidine solution, either by spraying
it against a cooled surface from which the material is removed
continuously, or by allowing the spray to drop through
a tower up which a counter current of cold air is passing
Preparation of p-Nitroguanidvne. Twenty-five cc of 61% aqueous
sulfunc acid is poured upon 20 grams of dicyandiamide contained in a
300-cc. round-bottom flask equipped with a reflux condenser. The mixture
warms up and froths considerably. After the first vigorous reaction
has subsided, the material is heated for 2 hours in an oil bath at
140° (thermometer in the oil). The reaction mass, chilled in a freezing