Indeed, the devil sits in the explosives, ready at any second to begin to destroy and break everything around. Keeping this creature of hell in check and releasing it only when required is the main problem that chemists and pyrotechnists have to solve when creating and using explosives. In the history of the creation and development of explosives (explosives), as in a drop of water, the history of the emergence, development and destruction of states and empires is displayed.
Preparing the outline of the lessons, the author repeatedly noticed that the countries whose rulers paid vigilant attention to the development of sciences, and above all to the natural trinity of mathematicians - physics - chemistry - reached heights in their development. A striking example can be the rapid ascent on the world stage of Germany, which in half a century made a leap from a union of disparate states, some of which even on a detailed map of Europe were difficult to see without a "small scope", to an empire that had to be reckoned with for a century and a half. Without diminishing the merits of the great Bismarck in this process, I will quote his phrase, which he said after the victorious end of the Franco-Prussian war: "This war was won by a simple German teacher." The author would like to devote his review to the chemical aspect of increasing the combat effectiveness of the army and the state, as always, without at all claiming to be exclusive of his opinion.
When publishing the article, the author, like Jules Verne, deliberately avoids specifying specific technological details and focuses his attention on purely industrial methods of obtaining explosives. This is due not only to the quite understandable sense of responsibility of the scientist for the results of his works (be it practical or journalistic), but also to the fact that the subject of the study is the question “Why was everything like this and not otherwise?” And not “Who was the first to get it? substance.
In addition, the author asks readers for forgiveness for the forced use of chemical terms - attributes of science (as shown by his own pedagogical experience, not the most beloved by schoolchildren). Realizing that it is impossible to write about chemicals without mentioning chemical terms, the author will try to minimize specialized vocabulary.
And the last thing. The figures given by the author should by no means be considered the ultimate truth. The data on the characteristics of explosives in different sources differ and sometimes quite strongly. This is understandable: the characteristics of ammunition very significantly depend on their "marketable" type, the presence / absence of foreign substances, the introduction of stabilizers, synthesis modes and many other factors. The methods for determining the characteristics of explosives are also not distinguished by uniformity (although there will be more standardization here) and they also do not suffer from special reproducibility.
BB classification
Depending on the type of explosion and sensitivity to external influences, all explosives are divided into three main groups:
1. Initiating BB.
2. Blasting explosives.
3. Throwing explosives.
Initiating BB. They are highly sensitive to external influences. The rest of their characteristics are usually low. But they have a valuable property - their explosion (detonation) has a detonation effect on blasting and propelling explosives, which are usually not sensitive to other types of external influences at all or have very low sensitivity. Therefore, initiating substances are used only to excite the explosion of blasting or propelling explosives. To ensure the safety of the use of initiating explosives, they are packed in protective devices (capsule, capsule sleeve, detonator cap, electric detonator, fuse). Typical representatives of initiating explosives: mercury fulminate, lead azide, tenres (TNPC).
Blasting explosives. This, in fact, is what they say and write about. They equip shells, mines, bombs, rockets, land mines; they blow up bridges, cars, businessmen …
Blasting explosives are divided into three groups according to their explosive characteristics:
- increased power (representatives: RDX, HMX, PETN, tetryl);
- normal power (representatives: TNT, melinite, plastic);
- reduced power (representatives: ammonium nitrate and its mixtures).
Explosives of increased power are somewhat more sensitive to external influences and therefore they are more often used in a mixture with phlegmatizers (substances that reduce the sensitivity of explosives) or in a mixture with explosives of normal power to increase the power of the latter. Sometimes high-power explosives are used as intermediate detonators.
Throwing explosives. These are various gunpowders - black smoky, smokeless pyroxylin and nitroglycerin. They also include various pyrotechnic mixtures for fireworks, signal and lighting flares, lighting shells, mines, and aerial bombs.
About black powder and Black Berthold
For several centuries, the only type of explosive used by humans was black powder. With its help, cannon balls were thrown at the enemy, and they were also filled with explosive shells. Gunpowder was used in underground mines to destroy the walls of fortresses, for crushing rocks.
In Europe, it became known from the 13th century, and even earlier in China, India and Byzantium. The first recorded description of gunpowder for fireworks was described by the Chinese scientist Sun-Simyao in 682. Maximilian the Greek (XIII-XIV centuries) in the treatise "Book of Lights" described a mixture based on potassium nitrate, used in Byzantium as the famous "Greek fire" and consisting from 60% nitrate, 20% sulfur and 20% coal.
The European history of the discovery of gunpowder begins with an Englishman, Franciscan monk Roger Bacon, who in 1242 in his book "Liber de Nullitate Magiae" gives a recipe for black powder for rockets and fireworks (40% saltpeter, 30% coal and 30% sulfur) and the semi-mythical monk Berthold Schwartz (1351). However, it is possible that this was one person: the use of pseudonyms in the Middle Ages was quite common, as was the subsequent confusion with the dating of sources.
The simplicity of the composition, the availability of two of the three components (native sulfur is still not uncommon in the southern regions of Italy and Sicily), the ease of preparation - all this guaranteed the gunpowder a triumphal march through the countries of Europe and Asia. The only problem was to obtain large quantities of potassium nitrate, but this task was successfully coped with. Since the only known at that time potash nitrate deposit was in India (hence its second name - Indian), local production was established in almost all countries. It was impossible to call him pleasant, even with a solid supply of optimism: the raw materials for him were manure, animal entrails, urine and animal hair. The least unpleasant ingredients in this foul-smelling and heavily soiled mixture were lime and potash. All this wealth was dumped for several months in pits, where it fermented under the influence of azotobacteria. The released ammonia was oxidized to nitrates, which ultimately gave the coveted nitrate, which was isolated and purified by recrystallization - an occupation, too, I would say, not the most pleasant one. As you can see, there is nothing particularly complicated in the process, the raw materials are quite affordable and the availability of gunpowder also soon became universal.
Black (or smoky) gunpowder was a universal explosive at that time. Neither wobbly nor roll, for many years it was used both as a projectile and as a filling for the first bombs - the prototypes of modern ammunition. Until the end of the first third of the 19th century, gunpowder fully met the needs of progress. But science and industry did not stand still, and soon it ceased to meet the requirements of the time due to its small capacity. The end of the gunpowder monopoly can be attributed to the 70s of the 17th century, when A. Lavoisier and C. Berthollet organized the production of berthollet salt based on potassium chlorate discovered by Berthollet (berthollet salt).
The history of Berthollet's salt can be traced back to the moment when Claude Berthollet studied the properties of chlorine recently discovered by Carl Scheele. By passing chlorine through a hot concentrated solution of potassium hydroxide, Berthollet obtained a new substance, later called by chemists potassium chlorate, and not by chemists - Berthollet's salt. It happened in 1786. And although the devil's salt never became a new explosive, it fulfilled its role: firstly, it served as an incentive to search for new substitutes for the decrepit “god of war”, and secondly, it became the founder of new types of explosives - initiators.
Explosive oil
And in 1846, chemists proposed two new explosives - pyroxylin and nitroglycerin. In Turin, the Italian chemist Ascagno Sobrero discovered that it was enough to treat glycerin with nitric acid (nitration) to form an oily transparent liquid - nitroglycerin. The first printed report about him was published in the journal L'Institut (XV, 53) on February 15, 1847, and it deserves some quotation. The first part says:
“Ascagno Sobrero, professor of technical chemistry from Turin, in a letter transmitted by prof. Peluzom, reports that he has long been receiving explosives by the action of nitric acid on various organic substances, namely cane sugar, beckoning, dextrite, milk sugar, etc. Sobrero also studied the effect of a mixture of nitric and sulfuric acids on glycerin, and experience showed him that a substance is obtained, similar to rattling cotton …"
Further, there is a description of the nitration experiment, interesting only to organic chemists (and even then only from a historical point of view), but we will only note one feature: nitro-derivatives of cellulose, as well as their ability to explode, were already quite well known then [11].
Nitroglycerin is one of the most powerful and sensitive blasting explosives and requires special care and attention when handling.
1. Sensitivity: may explode from being shot by a bullet. Sensitivity to impact with a 10 kg kettlebell dropped from a height of 25 cm - 100%. Combustion turns into detonation.
2. Energy of explosive transformation - 5300 J / kg.
3. Speed of detonation: 6500 m / s.
4. Brisance: 15-18 mm.
5. Explosiveness: 360-400 cubic meters. see [6].
The possibility of using nitroglycerin was shown by the famous Russian chemist N. N. Zinin, who in 1853-1855 during the Crimean War, together with the military engineer V. F. Petrushevsky, produced a large amount of nitroglycerin.
Professor of Kazan University N. N. Zinin
Military engineer V. F. Petrushevsky
But the devil living in nitroglycerin turned out to be vicious and rebellious. It turned out that the sensitivity of this substance to external influences is only slightly inferior to that of explosive mercury. It can explode already at the moment of nitration, it cannot be shaken, heated and cooled, or exposed to the sun. It may explode during storage. And if you set it on fire with a match, it can burn quite calmly …
And yet the need for powerful explosives by the middle of the 19th century was already so great that, despite numerous accidents, nitroglycerin began to be widely used in blasting operations.
Attempts to curb the evil devil were made by many, but the glory of the tamer went to Alfred Nobel. The ups and downs of this path, as well as the fate of the proceeds from the sale of this substance, are widely known, and the author considers it unnecessary to go into their details.
Being "squeezed" into the pores of an inert filler (and as such, several dozen substances were tried, the best of which was the infusorous earth - porous silicate, 90% of the volume of which falls on the pores that can greedily absorb nitroglycerin), nitroglycerin became much more "accommodating", preserving with him almost all his destructive power. As you know, Nobel gave this mixture, which looks like peat, the name "dynamite" (from the Greek word "dinos" - strength). The irony of fate: a year after Nobel received a patent for the production of dynamite, Petrushevsky completely independently mixes nitroglycerin with magnesia and receives explosives, later called "Russian dynamite".
Nitroglycerin (more precisely, glycerin trinitrate) is a complete ester of glycerin and nitric acid. It is usually obtained by treating glycerin with a sulfuric-nitric acid mixture (in chemical language - the esterification reaction):
The explosion of nitroglycerin is accompanied by the release of a large amount of gaseous products:
4 C3H5 (NO2) 3 = 12 CO2 + 10 H2O + 6 N2 + O2
Esterification proceeds sequentially in three stages: in the first, glycerol mononitrate is obtained, in the second - glycerol dinitrate, and in the third - glycerol trinitrate. For a more complete yield of nitroglycerin, a 20% excess of nitric acid is taken in excess of the theoretically required amount.
The nitration was carried out in porcelain pots or brazed lead vessels in a bath of ice water. About 700 g of nitroglycerin were obtained in one go, and during an hour such operations were performed in 3 - 4.
But the growing needs have made their own adjustments to the technology for producing nitroglycerin. Over time (in 1882), a technology for producing explosives in nitrators was developed. In this case, the process was divided into two stages: at the first stage, glycerin was mixed with half the amount of sulfuric acid, and thereby most of the released heat was utilized, after which a ready-made mixture of nitric and sulfuric acids was introduced into the same vessel. Thus, it was possible to avoid the main difficulty: excessive overheating of the reaction mixture. Stirring is carried out with compressed air at a pressure of 4 atm. The productivity of the process is 100 kg of glycerin in 20 minutes at 10 - 12 degrees.
Due to the different specific gravity of nitroglycerin (1, 6) and waste acid (1, 7), it collects from above with a sharp interface. After nitration, nitroglycerin is washed with water, then washed from acid residues with soda and again washed with water. Mixing at all stages of the process is carried out with compressed air. Drying is carried out by filtration through a layer of calcined table salt [9].
As you can see, the reaction is quite simple (recall the wave of terrorism at the end of the 19th century, raised by “bombers” who mastered the simple science of applied chemistry) and belongs to the number of “simple chemical processes” (A. Stetbacher). Almost any amount of nitroglycerin can be made in the simplest conditions (making black powder is not much easier).
The consumption of reagents is as follows: to obtain 150 ml of nitroglycerin, you need to take: 116 ml of glycerin; 1126 ml of concentrated sulfuric acid;
649 ml of nitric acid (at least 62% concentration).
Dynamite at war
Dynamite was first used in the Franco-Prussian War of 1870-1871: Prussian sappers blew up French fortifications with dynamite. But the safety of the dynamite turned out to be relative. The military immediately found out that when shot by a bullet, it explodes no worse than its progenitor, and combustion in certain cases turns into an explosion.
But the temptation to get powerful ammunition was irresistible. Through rather dangerous and complex experiments, it was possible to find out that dynamite will not detonate if the loads increase not instantly, but gradually, keeping the acceleration of the projectile within safe limits.
The solution to the problem at the technical level was seen in the use of compressed air. In June 1886, Lieutenant Edmund Ludwig G. Zelinsky of the 5th Artillery Regiment of the United States Army tested and refined the original American Engineering design. A pneumatic gun with a caliber of 380 mm and a length of 15 m with the help of air compressed to 140 atm, could throw projectiles with a length of 3.35 m from 227 kg of dynamite at 1800 m. thousand m
The driving force was provided by two cylinders of compressed air, and the upper one was connected to the tool by a flexible hose. The second cylinder was a reserve for feeding the upper one, and the pressure in it itself was maintained with the help of a steam pump buried in the ground. The dynamite-loaded projectile was in the shape of a dart - an artillery arrow - and had a 50-pound warhead.
The Duke of Cambridge ordered the army to test one such system in Milford Haven, but the gun used up almost all the ammunition before it finally hit the target, which, however, was destroyed very effectively. American admirals were delighted with the new cannon: in 1888, money was released to make 250 dynamite guns for coastal artillery.
In 1885 Zelinsky founded the Pneumatic Gun Company to introduce pneumatic guns with dynamite shells in the army and navy. His experiments made us talk about air guns as a promising new weapon. The US Navy even built the 944-tonne Vesuvius dynamite cruiser in 1888, armed with three of these 381mm guns.
Diagram of the "dynamite" cruiser "Vesuvius"
[center]
And this is how his stationary weapons emerging outward.[/center]
But a strange thing: after a few years, enthusiasm gave way to disappointment. "During the Spanish-American War," the American artillerymen said about this, "these guns never hit the right place." And although it was not so much about the guns as about the ability of the artillerymen to shoot accurately and the rigid fastening of the guns, this system did not receive further development.
In 1885, Holland installed Zelinsky's air cannon on his No. 4 submarine. However, it did not come to its practical tests, tk. the boat suffered a serious accident during launching.
In 1897, Holland re-armed his submarine No. 8 with a new Zelinsky cannon. The armament consisted of an 18-inch (457 mm) bow torpedo tube with three Whitehead torpedoes, as well as a Zelinsky aft air gun for dynamite shells (7 rounds of 222 lbs. 100.7 kg) each). However, due to the too short barrel, limited by the size of the boat, this gun had a short firing range. After practical shooting, the inventor dismantled it in 1899.
In the future, neither Holland nor other designers installed guns (apparatus) for firing throwing mines and dynamite shells on their submarines. So the guns of Zelinsky imperceptibly, but quickly left the stage [12].
Sibling of nitroglycerin
From a chemical point of view, glycerin is the simplest representative of the class of trihydric alcohols. There is its diatomic analogue - ethylene glycol. Is it any wonder that after getting acquainted with nitroglycerin, chemists turned their attention to ethylene glycol, hoping that it would be more convenient to use.
But here, too, the devil of explosives showed his capricious character. The characteristics of dinitroethylene glycol (this explosive never received its own name) turned out to be not much different from nitroglycerin:
1. Sensitivity: detonation when a 2 kg load falls from a height of 20 cm; sensitive to friction, fire.
2. Energy of explosive transformation - 6900 J / kg.
3. Speed of detonation: 7200 m / s.
4. Brisance: 16.8 mm.
5. Explosiveness: 620-650 cubic meters. cm.
It was first obtained by Henry in 1870. It is obtained by careful nitration of ethylene glycol according to a procedure similar to the preparation of nitroglycerin (nitrating mixture: H2SO4 - 50%, HNO3 - 50%; ratio - 1 to 5 in relation to ethylene glycol).
The nitration process can be carried out at a lower temperature, which is a predisposition to a higher yield [7, 8].
Despite the fact that, in general, the sensitivity of DNEG turned out to be somewhat lower than that of NG, its use did not promise significant benefits. If we add to this a higher volatility than that of NG, and a lower availability of raw materials, then it becomes clear that this path also led nowhere.
However, he also did not turn out to be completely useless. At first, it was used as an additive to dynamite, during the Second World War, due to the lack of glycerin, it was used as a substitute for nitroglycerin in smokeless powders. Such powders had a short shelf life due to the volatility of DNEG, but in wartime conditions this did not matter much: no one was going to store them for a long time.
Christian Schönbein Apron
It is not known how much time the military would have spent looking for ways to calm nitroglycerin, if by the end of the 19th century industrial technology for producing another nitroester had not arrived. Briefly, the history of its appearance is as follows [16].
In 1832, French chemist Henri Braconneau discovered that when starch and wood fibers were treated with nitric acid, an unstable, flammable and explosive material was formed, which he called xyloidin. True, the matter was limited to the message about this discovery. Six years later, in 1838, another French chemist, Théophile-Jules Pelouse, processed paper and paperboard in a similar way and produced a similar material, which he named nitramidine. Who would have thought then, but the reason for the impossibility of using nitramidine for technical purposes was precisely its low stability.
In 1845, the Swiss chemist Christian Friedrich Schönbein (who had become famous by that time for the discovery of ozone) was conducting experiments in his laboratory. His wife strictly forbade him to bring his flasks to the kitchen, so he was in a hurry to finish the experiment in her absence - and spilled some caustic mixture on the table. In an effort to avoid a scandal, he, in the best traditions of Swiss accuracy, wiped it off with his work apron, since there was not too much mixture. Then, also in the tradition of Swiss frugality, he washed the apron with water and hung it over the stove to dry. How long or short it hung there, history is silent, but that after drying the apron suddenly disappeared, it is known for certain. Moreover, he disappeared not quietly, in English, but loudly, one might even say enchanting: in a flash and a loud clap of an explosion. But here's what caught Schönbein's attention: the explosion occurred without the slightest plume of smoke!
And although Schönbein was not the first to discover nitrocellulose, it was he who was destined to draw a conclusion about the importance of the discovery. At that time, black powder was used in artillery, the soot from which soiled the guns that in the intervals between shots they had to be cleaned, and after the first volleys such a curtain of smoke rose that they had to fight almost blindly. Needless to say, the puffs of black smoke perfectly indicated the location of the batteries. The only thing that brightened up life was the realization that the enemy was in the same position. Therefore, the military reacted with enthusiasm to the explosive, which gives much less smoke, and besides, it is also more powerful than black powder.
Nitrocellulose, devoid of the shortcomings of black powder, made it possible to establish the production of smokeless powder. And, in the traditions of that time, they decided to use it both as a propellant and as an explosive. In 1885, after numerous experimental works, the French engineer Paul Viel received and tested several kilograms of pyroxylin flaky powder, called gunpowder "B" - the first smokeless powder. Tests have proven the benefits of the new propellant.
However, it was not easy to establish the production of large quantities of nitrocellulose for military needs. Nitrocellulose was too impatient to wait for battles and factories, as a rule, flew into the air with enviable regularity, as if competing with nitroglycerin production. The development of the technology for the industrial production of pyroxylin had to overcome obstacles like no other explosive. It took a whole quarter of a century to carry out a number of work by researchers from different countries until this original fibrous explosive became suitable for use and until numerous means and methods were found that somehow guaranteed against an explosion during prolonged storage of the product. The expression "in any way" is not a literary device, but a reflection of the difficulty that chemists and technologists have encountered in defining stability criteria. There was no firm judgment about the approaches to determining the stability criteria, and with the further expansion of the scope of use of this explosive, constant explosions revealed more and more mysterious features in the behavior of this peculiar complex ether. It wasn't until 1891 that James Dewar and Frederick Abel managed to find a safe technology.
The production of pyroxylin requires a large number of auxiliary devices and a lengthy technological process, in which all operations must be carried out equally carefully and thoroughly.
The initial product for the production of pyroxylin is cellulose, the best representative of which is cotton. Natural pure cellulose is a polymer consisting of glucose residues, which is a close relative of starch: (C6H10O5) n. In addition, waste from paper mills can provide excellent raw materials.
Fiber nitration was mastered on an industrial scale back in the 60s of the 19th century and was carried out in ceramic pots with further spinning in centrifuges. However, by the end of the century, this primitive method was supplanted by American technology, although during the WWI it was revived due to its low cost and simplicity (more precisely, primitivism).
Refined cotton is loaded into a nitrator, a nitrating mixture (HNO3 - 24%, H2SO4 - 69%, water - 7%) is added based on 15 kg of fiber 900 kg of the mixture, which gives a yield of 25 kg of pyroxylin.
The nitrators are connected in batteries, consisting of four reactors and one centrifuge. The nitrators are loaded with a time interval (approximately 40 minutes) equal to the extraction time, which ensures the continuity of the process.
Pyroxylin is a mixture of products with varying degrees of cellulose nitration. Pyroxylin obtained by using phosphoric acid instead of sulfuric acid is highly stable, but this technology did not take root due to its higher cost and lower productivity.
The pressed pyroxylin has the property of self-igniting and needs to be moistened. The water used for washing and stabilizing pyroxylin should not contain alkaline agents, since the products of alkaline destruction are autoignition catalysts. Final drying to the required moisture content is achieved by flushing with absolute alcohol.
But wetted nitrocellulose is also not free from troubles: it is susceptible to infection by microorganisms that cause mold. Protect it by waxing the surface. The finished product had the following characteristics:
1. The sensitivity of pyroxylin is highly dependent on humidity. Dry (3 - 5% moisture) easily ignites from an open flame or touch of a hot metal, drilling, friction. It explodes when a 2 kg load falls from a height of 10 cm. With an increase in humidity, the sensitivity decreases and at 50% water, the ability to detonate disappears.
2. Energy of explosive transformation - 4200 MJ / kg.
3. Speed of detonation: 6300 m / s.
4. Brisance: 18 mm.
5. High explosiveness: 240 cubic meters. cm.
And yet, despite the shortcomings, the chemically more stable pyroxylin suited the military more than nitroglycerin and dynamite, its sensitivity could be adjusted by changing its moisture content. Therefore, pressed pyroxylin began to find wide use for equipping warheads of mines and shells, but over time, this unmatched product gave way to nitrated derivatives of aromatic hydrocarbons. Nitrocellulose remained as a propellant explosive, but as a blasting explosive it has become a thing of the past forever [9].
Volatile jelly and nitroglycerin gunpowder
“Black powder … represents all the makings of further improvement - through the scientific study of invisible phenomena occurring during its combustion. Smokeless gunpowder is a new link between the power of countries and their scientific development. For this reason, being one of the warriors of Russian science, in my declining strength and years I dare not analyze the tasks of smokeless gunpowder …"
The reader, even a little familiar with the history of chemistry, probably already guessed whose words these are - the brilliant Russian chemist D. I. Mendeleev.
Mendeleev devoted a lot of energy and attention to porrocheliy as a field of chemical knowledge in the last years of his life - in 1890-1897. But, as always, the active phase of development was preceded by a period of reflection, accumulation and systematization of knowledge.
It all began with the fact that in 1875 the indefatigable Alfred Nobel made another discovery: a plastic and elastic solid solution of nitrocellulose in nitroglycerin. It quite successfully combined a solid form, high density, ease of molding, concentrated energy and insensitivity to high atmospheric humidity. The jelly, completely burned into carbon dioxide, nitrogen and water, consisted of 8% dinitrocellulose and 92% nitroglycerin.
Unlike the techie Nobel, D. I. Mendeleev proceeded from a purely scientific approach. He based his research on a completely definite and chemically strictly substantiated idea: the required substance during combustion should emit a maximum of gaseous products per unit weight. From a chemical point of view, this means that there should be enough oxygen in this compound to completely convert carbon into gaseous oxide, hydrogen into water, and the oxidizing capacity to provide energy for this entire process. A detailed calculation led to the formula of the following composition: C30H38 (NO2) 12O25. When burning, you should get the following:
C30H38 (NO2) 12O25 = 30 CO + 19 H2O + 6 N2
It is not an easy task to carry out a targeted synthesis reaction of a substance of such composition, even at present, therefore, in practice, a mixture of 7-10% nitrocellulose and 90-93% nitroglycerin was used. The percentage of nitrogen content is about 13, 7%, which is slightly higher than that for pyrocollodia (12, 4%). The operation is not particularly difficult, does not require the use of complex equipment (it is carried out in the liquid phase) and proceeds under normal conditions.
In 1888, Nobel received a patent for gunpowder made of nitroglycerin and colloxylin (low-nitrated fiber), named like pyroxylin smokeless gunpowder. This composition is used practically unchanged to this day under various technical names, the most famous of which are cordite and ballistite. The main difference is in the ratio between nitroglycerin and pyroxylin (in cordite it is higher) [13].
How do these explosives relate to each other? Let's look at the table:
Table 1.
BB …… Sensitivity…. Energy… Speed …… Brisance… High-explosiveness
……… (kg / cm /% of explosions)….explosion….detonation
GN ……….2 / 4/100 ………… 5300 ……..6500 ………..15 - 18 ………. 360 - 400
DNEG …… 2/10/100 ………..6900 ……… 7200 ……….16, 8 …………… 620 - 650
NK ……… 2/25/10 ………… 4200 ……… 6300 ………..18 ……………. 240
The characteristics of all explosives are quite similar, but the difference in physical properties dictated different niches of their application.
As we have already seen, neither nitroglycerin nor pyroxylin pleased the military with their character. The reason for the low stability of these substances, it seems to me, lies on the surface. Both compounds (or three - counting and dinitroethylene glycol) are representatives of the class of ethers. And the ester group is by no means one of the leaders in chemical resistance. Rather, she can be found among the outsiders. The nitro group, which contains nitrogen in a rather strange oxidation state of +5 for it, is also not a model of stability. The symbiosis of this strong oxidizing agent with such a good reducing agent as the hydroxyl group of alcohols inevitably leads to a number of negative consequences, the most unpleasant of which is capriciousness in application.
Why did chemists and the military spend so much time experimenting with them? As it seems, many and many have won over. The military - the high power and availability of raw materials, which increased the combat effectiveness of the army and made it insensitive to delivery in wartime. Technologists - mild synthesis conditions (no need to use high temperatures and elevated pressure) and technological convenience (despite the multistage processes, all reactions proceed in one reaction volume and without the need to isolate intermediate products).
The practical yields of products were also quite high (Table 2), which did not cause an urgent need to search for sources of large quantities of cheap nitric acid (the issue with sulfuric acid was resolved much earlier).
Table 2.
BB …… Consumption of reagents per 1 kg….. Number of stages…. Number of emitted products
……… Nitric to-that.. Sulfur to-that
GN …….10 ……………..23 ……………..3 …………………… 1
DNEG….16, 5 …………..16, 5 …………… 2 …………………… 1
NK ……..8, 5 …………… 25 ……………..3 …………………… 1
The situation changed dramatically when new incarnations of the devil of explosives appeared on the scene: trinitrophenol and trinitrotoluene.
(To be continued)
