NITRO-GLYCERIN. Syn. Glonoin, Nitrate of Glyceryl, Trinitrite, Nitroleum, Fulminating oil, Tri-nitroglycerin. This dangerously explosive compound, from the use of which in mining, quarrying, and such like operations so many fatal accidents have occurred, is glycerin in which 3 atoms of hydrogen have been replaced by 3 molecules of nitroxyl (NO2), as illustrated by the following formulæ:
It was discovered in 1847 by Dr. Sobrero, a pupil of Pelouze.
Kopp prepares nitro glycerin by mixing 3 parts of sulphuric acid, of sp. gr. of 1·767, with 1 part of fuming nitric acid. 2800 grammes of the mixed acids are added to 350 grammes of glycerin, great care being necessary to avoid any elevation of temperature, which would lead to a violent reaction, resulting in the conversion of the glycerin into oxalic acid.
After standing 5 or 10 minutes, the mixture is poured into four or six times its bulk of very cold water to which a rotatory motion has been imparted. The nitro-glycerin falls to the bottom of the vessel as an oily-looking liquid, which is washed by decantation. The manufacture of nitro-glycerin is attended
with considerable danger, since very slight friction or pressure is sufficient to determine its explosion. Hence many methods have been suggested for guarding against accidents from it during storage. One of these consists in mixing it with finely powdered glass.
Wurtz advises the nitro-glycerin to be mixed with solutions of nitrate of lime, zinc, or magnesia, the solutions to have a sp. gr. equal to the nitro-glycerin. By this means a harmless emulsion would be formed, and the nitro-glycerin would be recoverable when required for use by simply adding water. Nobel’s plan consists in dissolving it in wood spirit.
Prop. Nitro-glycerin is a fluid of a yellow or brownish colour, having a sp. gr. of 1·6. It dissolves in alcohol, ether, and wood naphtha, from all of which it may be recovered by the addition of water. Dissolved in either of these solutions it becomes converted into a crystalline mass when exposed to a low temperature. If subjected to a blow it explodes with fearful violence, a single drop placed upon paper, and struck upon an anvil, giving rise to a report that is almost deafening. Neither a spark nor the application of a lighted body is said to cause its ignition, which takes place with difficulty even if it be applied to a thin layer of the substance. 100 parts of nitro-glycerin yield on combustion:
| Water | 20 | parts. |
| Carbonic acid | 58 | ” |
| Oxygen | 3·5 | ” |
| Nitrogen | 18·5 | ” |
| ——— | ||
| 100·0[48] |
[48] Wagner.