For several centuries, people have been known to only one explosive - black powder, widely used both in war and peace during blasting operations. But the second half of the XIX century was marked by the invention of a whole family of new explosives, destructive force that hundreds and thousands of times superior to the power of gunpowder. Their creation was preceded by several discoveries. Even in 1838, Peluso spent the first experiments on the nitration of organic substances. The essence of this reaction is that many carbonaceous material when treated with a mixture of concentrated nitric and sulfuric acids give a hydrogen, a nitro group instead take NO2 and converted into a powerful explosive. Other chemists have investigated this interesting phenomenon. In particular, Shenbeyn, nitriruya cotton, in 1846 received a gun-cotton. In 1847, while working in a similar way to the glycerin, Sobrero discovered nitroglycerin - explosive, has great destructive power. At first, nobody was interested in nitroglycerin. Sobrero himself only 13 years later returned to their experiences and described the precise way nitration of glycerin. After that a new substance has found a use in the mining industry. Initially, it was poured into the hole, and stopped it with clay and blew through his immersion in the cartridge. However, the best effect is achieved when the ignition capsule with mercury fulminate.
What explains the exceptional explosive power of nitroglycerin? It has been found that it occurs in the explosion decomposition, whereby first gases produced CO2, CO, H2, CH4, N2 and NO, which interact again with the release of huge amounts of heat. The final reaction can be expressed by the formula:
2C3H5 (NO3) 3 = 6CO2 + 5H2O + 3N + 0, 5O2.
Heated to immense temperatures, these gases are rapidly expanding, providing the environment a lot of pressure. The end products of the explosion are completely harmless. All this seemed to make nitroglycerin indispensable for underground blasting, but it soon turned out that the production, storage and transportation of liquid explosives are fraught with many dangers.
In general, pure nitroglycerin is quite difficult to ignite an open fire. A lit match rotten in it without any consequences. But its sensitivity to impacts and shocks (detonation) was many times higher than that of black powder. Upon impact, often very slight, in the layers affected by concussion, there was a rapid increase in temperature before the explosive reaction. Mini explosion first layers producing a new blow to the deeper layers, and so it went until, until there is an explosion of matter throughout the mass. Sometimes, without any influence from outside nitroglycerin suddenly began to decompose into organic acids, quickly darkened and then it was satisfied with the negligible shake the bottle to cause a violent explosion. After a series of accidents nitroglycerin use was almost universally banned. But industrialists who began to produce this explosive had two choices - either find a condition in which the nitroglycerin is less sensitive to detonation or curtail their production.
One of the first interested in nitroglycerine Swedish engineer Alfred Nobel, who founded a factory for his release. In 1864, his factory blown up together with the workers. He killed five people, including Alfred's brother Emil, who just turned 20 years old. After this disaster Nobel threatened with significant losses - it was not easy to convince people to invest money in such a dangerous venture. For several years he studied the properties of nitroglycerin and eventually managed to establish quite secure its production. But there was the problem of transportation. After many experiments Nobel found that nitroglycerin dissolved in an alcohol less sensitive to detonation. However, this method does not give full reliability. The search continued, and then an unexpected event helped to solve the problem brilliantly. When transporting bottles of nitroglycerin to moderate shaking, they were placed in the diatomaceous earth - especially diatomaceous earth, mined in Hanover. Diatomaceous earth consists of siliceous shells of algae with a lot of cavities and tubular. And once when sending a bottle of nitroglycerin was smashed and its contents spilled on the ground. At Nobel had an idea to make some experiments with the impregnated diatomaceous earth nitroglycerin. It turns out that does not diminish the explosive properties of nitroglycerine from the fact that it has absorbed the porous earth, but its sensitivity to detonation decreased several times. In this state, it does not explode either by friction or by a weak shock or by burning. But when ignited a small amount of mercury fulminate in the metal cap is an explosion of the same force, which gave the same amount of pure nitroglycerin. In other words, it was just what you need, and even much more than that, he hoped to get the Nobel. In 1867 he took out a patent on the discovery of the compound that is called dynamite.
The explosive power of dynamite as huge as that of nitroglycerine: 1 kg of dynamite in 1/50000 seconds develops strength in kgm 1,000,000, that is sufficient to raise the 1,000,000 kg per 1 m In addition, if 1 kg of black powder converted into gas for. 0, 01 seconds, then 1 kg of dynamite - after 0, 00,002 seconds. But with all this quality made dynamite exploded only on a very strong impact. Lighted touch the fire, it gradually burned without explosion, a bluish flame. Explosion occurs only when the ignition is a large mass of dynamite (over 25 kg). Undermining dynamite and nitroglycerine as a best be carried out by means of detonation. For this purpose, in the same Nobel 1867, he invented priming cap gremuchertutny. Dynamite immediately found wide application in the construction of highways, tunnels, canals, railways and other facilities, which explains the rapid growth of the state of its inventor in many ways. The first factory for the production of dynamite Nobel founded in France, then it has established its production in Germany and England. For thirty years, trade with dynamite brought Nobel enormous wealth - about 35 million crowns.
The process of manufacture of dynamite was limited to several transactions. First of all, necessary to get nitroglycerine. It was the most difficult and dangerous moment in the whole production. nitration reaction took place, if one part of the three parts of glycerol was treated with concentrated nitric acid in the presence of 6 parts of concentrated sulfuric acid. The equation was as follows:
C3H5 (OH) 3 + 3HNO3 = C3H5 (NO3) 3 + 3H2O.
Sulfuric acid in the compound was not involved, but its presence was necessary, firstly, for the absorption released in the reaction of the water, which otherwise, diluting nitric acid, thereby would prevent the completeness of the reaction, and, secondly, to isolate the resulting nitroglycerin solution of nitric acid, as it is, being highly soluble in this acid is not dissolved in a mixture thereof with sulfuric acid. Nitration accompanied by a strong release of heat. Moreover, due to heating if the mixture temperature rose above 50 degrees, the reaction would be headed over to the other side - to nitroglycerin started oxidation, accompanied by rapid release of nitrogen oxides, and even more heat, which would lead to an explosion. Therefore nitration needed to maintain a constant cooling of the mixture of acids and glycerol by adding the latter gradually and constantly stirring each serving. Formed directly in contact with nitroglycerine acids, having a lower density compared with the acidic mixture, surfaced, and it can be easily assembled by the end of the reaction.
Preparation of the acid mixture Nobel factories occurred in large cylindrical cast-iron containers, where the mixture enters the so-called nitratsionny apparatus.
The device consisted of a lead vessel A, which was placed in a wooden vat B and closed the lid of lead L, which is plastered with the cement. After the cover were the two ends of the lead coils D, positioned inside the device (through them constantly supplied cold water). A tube C into the machine and fed cold air to stir the mixture. The tube is averted from the apparatus F nitric acid vapors; G tube was used for pouring a metered amount of acid mixture; through a tube H poured glycerin. The vessel was metered out necessary quantity M of this substance, which is then injected into the compressed nitrogen mixture through the intake air through the tube O. In this setup could process a time of about 150 kg glycerol. To let the required amount of acid mixture and refrigerate it (passing the cold compressed air and cold water through coils) to 15-20 degrees, started to inject chilled glycerol. It should be that the temperature in the apparatus did not rise above 30 degrees. If the temperature of the mixture began to rise rapidly and approaching the critical contents of the tank can be rapidly released in large bowl with cold water.
Operation Education nitroglycerin lasted about one and a half hours. After this mixture entered the separator - lead quadrangular box with a conical bottom and two valves, one of which was located at the bottom, and the other - on the side. Once the mixture is settled and separated, nitroglycerin released through the upper valve, and an acid mixture of - through the bottom. The resulting nitroglycerin washed several times excess of acid as the acid, it can start to react with and cause its decomposition, which will inevitably lead to an explosion. To avoid this, a hermetic vat of nitroglycerin fed water and stirred with compressed air. The acid is dissolved in water, as well as the density of water and nitroglycerin were very different, then separate them from each other is not too difficult. To remove residual water, nitroglycerin was passed through several layers of felt and salt. As a result of all these actions was obtained oily liquid yellowish odorless and very toxic (poisoning may occur both by inhalation and by ingestion of nitroglycerine droplets on the skin). When heated above 180 degrees it exploded with a terrible destructive force.
Cooked nitroglycerine mixed with diatomaceous earth. Before this kieselguhr and washed thoroughly pulverized. Soaking his nitroglycerine happened in wooden boxes lined inside with lead. After mixing nitroglycerin dynamite rubbed through a sieve and packed in parchment cartridges.
The kieselguhr dynamite nitroglycerin only participated in the explosive reaction. In the future Nobel invented nitroglycerine impregnate various grades of gunpowder. In this case, the powder is also involved in the reaction and significantly increased the force of the explosion.