The Chemistry of Powder and Explosives - Sciencemadness Dot Org

234 NITRIC ESTERS
about 775& of that of nitroglycerin, but the relatively greater
brisance results from the low viscosity of the substance which
gives it a higher velocity of detonation. Naoum also reports that
a 93% trimethylene glycol dinitrate gelatin with 7% collodion
cotton gave an expansion of 470 cc. or about 80% as much as a
similar nitroglycerin gelatin,
Propylene Glycol Dinitrate (Methylglycol dinitrate, methylnitroglycol)
Propylene occurs along with ethylene in cracking gas. Its use
as a raw material for the synthesis of glycerin has already been
mentioned in the section on nitroglycerin. It yields propylene
glycol when subjected to the same chemical processes as those
which are used for the preparation of glycol from ethylene. 59
Propylene glycol shows the same tendency toward oxidation
during nitration that trimethylene glycol does, but to a less
extent; noticeable decomposition occurs only above 30°,
CHs CH3 CHs CH3
i HOQ I HOH I nitration I
H > CH—OH — > CH—OH — > CH—ONO2
CH2 CH*—Cl CHj—OH CHi—ONO2
Propylene glycol dinitrate is a colorless liquid of characteristic
aromatic odor, more volatile and less viscous than trimethylene
glycol dinitrate with which it is isomeric. Its specific gravity
(20°/4°) is 1.368 at 20°. It boils at 92° at 10 mm., and does not
freeze at —20°. Its solubilities, gelatinizing power, and explosive
properties are substantially the same as those of its isomer.
Indeed, Naoum 80 reports that it gave exactly the same expansion
as trimethylene glycol dinitrate in the Trauzl lead block test,
namely, 540 cc.
59 Symmes, in a footnote, p. 375, in his English translation of Naoum's
book, op. cit., cites U. S. patents 1,307,032, 1,307,033, 1,307,034, and 1,371,215
which describe a method for the manufacture of mixed ethylene and propylene
glycols from cracking gas, satisfactory methods for the nitration of
the mixture and for the stabilization of the mixed nitric esters, and explosives
made from the products "which practical tests in actual use showed
could not be frozen even at temperatures prevailing in winter along the
Canadian border, or -10° to -30° F."
e°Op. tit., p. 237.