Diethyl glycol dinitrate
Diethyl glycol dinitrate ONO2(CH2)2-O-(CH2)2ONO2 is a nitrated alcohol ester produced by the action of concentrated nitric acid (s.g. 1.5), normally admixed with an excess of strong sulfuric acid (s.g. >1.8) as a dehydrating agent, upon diglycol, the oxidative dimer of glycol (dihydroxy ethylene). Ethylene is a small hydrocarbon, gaseous at room temperature, readily inflammable but toxic only in concentration. Derived from petrochemical fractionation or vegitative fermentation, it has a number of industrial uses and is a critical feedstock for plastics manufacture.
Diethyl glycol dinitrate is a colorless, oderless, viscous, oily liquid, specific gravity (s.g.) 1.4092 at 0oC and 1.3846 at 20oC; freezing point -11.5oC under a standard atmosphere, the theoretical boiling point of approximately 197oC difficult to confirm as the compound begins to decompose and spontaneously inflames at or slightly below this temperature. Partial pressure is reported as .007mm Hg at 22.4oC and 760mm Hg. It is readly miscible in most non-polar solvents, methanol, and cold acetic acid. Solubility in water (4.1gm/L at 24oC) and ethanol is very low. While chemically similar to a number of powerful high explosives, pure diethyl glycol dinitrate is extremely hard to initiate and will not propagate a detonation wave. It inflames only with difficulty (requiring localized heating to decomposition point) unless first atomized, and burns placidly even in quantity.
Mixed with nitrocellulose and extruded under pressure, diethyl glycol dinitrate forms a tough colloid whose characteristics (good specific impulse, moderate burn rate and temperature, great resistance to accidental ignition and casual handling) make it well suited as a solid propellant for rocketry. It was widely used in this capacity, by both sides, during World War 2. It also found use as a "productive" desensitizer (one that contributes to the overall power of the explosion rather than having a neutral or negative effect) in nitroglycerine and nitroglycol based explosives (such as dynamite and blasting gelatin).
If ingested, it, like nitroglycerine, produces rapid vasodialation through the release of nitrogen monoxide, NO, a physiological signaling molecule that acts to relax smooth muscle. As such it has occasionally been used medically to relieve angina, substernal chest pain associated with impaired cardiac circulation, since the concurrent headache it induces is somewhat less severe than other nitro compounds.
At present interest in the chemical seems to be mostly historical: more potent perchlorate/metal mixtures have long since supplanted it as a solid propellant; safer explosives have replaced nitroglycerine, true dynamites (the term is often used generically, even by experienced field technicians, to refer to almost any explosive supplied in small, discrete packages) retaining only a few specialist uses. The medical application was never widespread, the standard nitroglycerine being faster acting and almost literally dirt cheap; oral nitrates in any case being only palliative, not an effective treatment.
The preparation and properties of diethyl glycol dinitrate were reported in detail by W. H. Rinkenbach in Industrial Engineering Chemistry v19 p925 (1927) Note: the present author has transliterated some terminology and notation in line with modern practice.
Military applications referenced in Encyclopedia of Weapons of World War 2; Gen. Ed. Chris Bishop, c.2003 Friedman/Fairfax NYNY, ISBN 1-58663-762-2