Nitroglycerin

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Nitroglycerin
NG structure.png
Names
Preferred IUPAC name
Propane-1,2,3-triyl trinitrate
Other names
1,2,3-Tris(nitrooxy)propane
Glyceryl trinitrate
Nitro-dur
Nitroglycerol
Nitrostat
Trinitroglycerin
Trinitroglycerine
Properties
C3H5N3O6
Molar mass 227.09 g/mol
Appearance Colorless to pale-yellow liquid
Odor Odorless
Density 1.6 g/cm3 (at 15 °C)
Melting point 14 °C (57 °F; 287 K)
Boiling point 50 °C (122 °F; 323 K) (explodes)
0.138 g/100 ml (at 20 °C)
Solubility Miscible with 1,2-dibromoethane, glacial acetic acid, dichloroethylene, ethyl acetate, nitrobenzene, pyridine
Slightly soluble in carbon disulfide, ethanol, methanol
Poorly soluble in glycerol, liq. petrolatum, oleic acid, petroleum ether, toluene
Solubility in carbon disulfide 0.833 g/100 ml
Solubility in ethanol 25 g/100 ml
Solubility in methanol 5.55 g/100 ml
Vapor pressure 0.0003 mmHg (at 20 °C)
Thermochemistry
−370 kJ/mol
Hazards
Safety data sheet CPCB
Related compounds
Related compounds
Ethylene glycol dinitrate
1,2,4-Butanetriol trinitrate
Erythritol tetranitrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Nitroglycerin (NG), more correctly called glycerol trinitrate, is the nitrate ester of glycerol. It is one of the most commonly used explosives, found in dynamites, blasting gelatine and smokeless powders.

Properties

Physical

Nitroglycerin is a dense (1.59 g/cm3), oily, colourless liquid with freezing point 14 °C. It is a solvent for nitrocellulose, and the resulting gel is known as blasting gelatine (blasting jelly).

Explosive

Nitroglycerin is a powerful explosive, similar to ethylene glycol dinitrate. It is highly sensitive to impact, but incomplete detonation result from everything but a strong initiation. This causes its lead block test value to be dependent on the strength of initiation:

detonator No.1 ... 190 cm3
detonator No.2 ... 225 cm3
detonator No.6 ... 460 cm3
detonator No.8 ... 590 cm3

Availability

Nitroglycerin pills contain a very small amount of nitroglycerin, impractical for extraction and use (though some types of pills will burn if ignited).

The classic dynamite contains NG mixed with kieselgur (diatomaceous earth), to make it stable. Most smokeless powders contain nitro. Extracting the nitroglycerin from these products however, is impractical and dangerous for large quantities.

Preparation

Nitroglycerin is prepared by the nitration of glycerol using a concentrated mixture of nitric and sulfuric acids in an ice bath, at very low temperatures. The information in this article is not enough to attempt such a synthesis though, as the risks are very high with this compound.

Projects

  • Dynamite
  • Smokeless powder
  • Various propellents

Handling

Safety

Nitroglycerin is a dangerously sensitive and extremely powerful explosive. Improperly neutralized it is even more sensitive. It is also toxic by skin contact and inhalation. As a strong vasodilator, it results in severe headaches, though it is used medicinally in very low concentrations.

Storage

Never store liquid nitroglycerin, even for short periods!

Dynamite, which consists of nitroglycerin mixed with diatomite, is much more stable, though over time the dynamite will "sweat" or "weep" its nitroglycerin, which can then pool in the bottom of the box or storage area and can explode.

Disposal

Nitroglycerin can be neutralized by carefully diluting it first in a solvent, then slowly adding it dropwise in a diluted solution of sodium hydroxide or being exposed to sunlight for a while, also diluted. Concentrated stuff may explode.

References

Chemistry and Technology of Explosives - Volume II, first edition, 1965.

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