Hydrazine Hydrate

Product chemical formula: H 2 NNH 2 .H 2 O

Trade designations of the product:

1.Hydrazine hydrate

2. Hydrazine monohydrate

3. Hydrazine hydroxide

4.Hydrazine Anhydrous

5.Hydrazine Aqueous Solution

Product description.

Hydrosine hydrateis a stable chemical. Hydrosine hydrate It is a clear liquid with corrosive properties, as well as a strong ammonia odor. Hydrosine hydrate also has characteristic fuming properties. Hydrosine hydrate has unique Chemical properties, allowing it to dissolve not only in water, but also in a wide range of alcohol solutions. When heated or exposed to direct rays, hydrazine hydrate decomposes to form substances such as ammonia, hydrogen and nitrogen. These chemical properties can result in an extremely violent reaction of an explosive nature if product exposed to metal group catalyst agents, such as platinum or Raney nickel. Hydrosine hydrate obtained from ammonia containing chloramine by adding glue or gelatin to the reaction, which allow inhibiting the decomposition of hydrazine by unreacted oxidizing agents, the final product is hydrazine in the hydrated form. 100% of the final product contains up to 64% by weight of pure hydrazine. Hydrazine is also prepared from sodium hypochlorite with urea in the presence of glue or gelatin. Ammonia and amines are nitrogen nucleophiles that donate electrons (they are Lewis bases). But the diamine hydrazine has much stronger nucleophilicity, making it more reactive than ammonia.

Hydrosine hydrateIt has dibasic and highly reactive properties. Hydrazine used as a component in the industrial production of jet fuel because it produces a large amount of heat when burned. Hydrazine hydrate less flammable and less chemically volatile than hydrocarbon fuels, which qualitatively distinguishes it from alternative sources fuel. Hydrosine hydrate is relatively environmentally friendly, since they quickly degrade in environment, thereby preventing not only the long-term formation in the rocks, but also prevents the formation of dangerous foci of chemical contamination. Hydrazine hydrate used as an oxygen scavenger for boiler water systems and space heating systems to prevent corrosion damage during equipment use. Hydrazine hydrate used as a reducing agent for the extraction of precious metals. It is used as a polymerization catalyst and chain extender in urethane coatings. Most hydrazine derivatives, however, are only intermediates in chemical reactions. They have active applications in organic synthesis for agrochemicals, pharmaceuticals, photographic, heat stabilizers, polymerization catalysts, fire retardants, blowing agents for plastics, explosives, and dyes. Recently, hydrazine has been applied to LCDs (liquid crystal displays) as a fuel, to make transistors faster than their thin-film counterparts.

Hydrazoneis a compound containing a -NH N:C- group. It is formed from the condensation reaction of aldehydes or ketones with hydrazine (usually phenylhydrazine). It is used as an exotic fuel. Aromatic hydrazines are used to form indole via a cyclization reaction (Fischer synthesis). Hydrazones and hydrazines are converted to aldehydes and ketones, according to a chemical reaction, subsequently hydrocarbons are obtained by heating the carbonyl compound with sodium ethoxide (Wolf-Kischner reduction). Organic azides are compounds with a substituted hydrocarbon group, as in alkyl or aryl with hydrazoic acid. Acylhydrazine hydrazide is an organic radical formed by the removal of a hydroxyl group from an organic acid (carboxy group). Organic azides can be used for the synthesis of target compounds. They act as electrophiles on the nitrogen attached to the carbon and complement the property of an electron-donating character for the neighboring carbon.

Physical and chemical properties of hydrazine hydrate.

Storage and transportation of hydrazine hydrate.

Appeal Hydrazine hydrate: Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Ground and secure containers when transporting material. Use non-sparking tools and explosion-proof equipment. Avoid contact with eyes, skin or clothing. Empty containers contain product residues (liquid and/or vapor) and may be hazardous. Store in a tightly closed container. Do not swallow or inhale. Do not violate sealing regulations, do not cut, weld, tin, drill, grind or expose empty containers to heat, sparks or open flames. Keep away from heat, sparks and flames. Use only with adequate ventilation or respiratory protection.

Storage Hydrazine hydrate: Keep away from heat, sparks and flames. Keep away from sources of ignition. Do not store in direct sunlight. Store in a cool, dry, well ventilated area, away from incompatible substances. Isolate from oxidizing materials and acids.

Chemical stability: Thermally unstable.

Incompatibility with other materials: The substance is highly reactive. Incompatible with oxidizing agents (including air), acids and some metal and metal oxides. The substance may spontaneously ignite in air on contact with porous materials. Ignites on contact with nitrous oxide and tetroxide, hydrogen peroxide, tetryl, and nitric acid. Explodes on contact with potassium, silver compounds, sodium hydroxide, titanium and difluoride compounds. Also incompatible with barium oxide or calcium oxide, benzeneselenic acid or calcium anhydride.

Applications of hydrazine hydrate.

1. Hydrazine hydrate buy and use industrial nickel plating cycle.

2. Hydrazine hydrate used as a halogen remover in wastewater.

3. Hydrazine hydrate buy and use as a corrosion inhibitor.

4.Hydrazine hydrate used in non-slip stages of photo development.

5. Hydrazine hydrate used as a boiler water treatment agent.

6. Hydrazine hydrate used in the industrial production of plastics using foaming technology.

7. Hydrazine hydrate buy and use for industrial production vinyl floor coverings and for the production of substances for creating foam pads.

8. Hydrazine hydrate used in the agricultural industry as a raw material for the production of chemicals such as maleic hydrazide.

9. Hydrazine hydrate buy and use a reducing agent in the nuclear fuel reprocessing process.

10. Hydrazine hydrate buy in order to be used in the medical industry to synthesize drugs for the treatment of several types of cancer.

The plant for the production of hydrazine in Russia was built as part of the organization of the production of strategic, scarce and import-substituting materials. It is located in Nizhny Novgorod region, design capacity - 15 tons per year. At present, complex tests of the equipment are underway.

The production of hydrazine and heptyl (unsymmetrical dimethylhydrazine) in Russia was curtailed in the 1990s. Since then, hydrazine has been purchased from abroad, mainly from Germany. In 2014, after the aggravation of relations with the countries of the Western bloc, the supply of hydrazine to the Russian Federation ceased.

In October 2014, the sanctions were partially relaxed: the Council of the European Union allowed the supply of hydrazine and heptyl to Russia in cases where the fuel is purchased for the implementation of joint programs with the European Space Agency or for launches of European spacecraft. The sellers were instructed to ensure that Russian companies buy exactly the right amount of fuel for a specific project.

The embargo had no effect on space programs. More precisely, it has not yet had time to have an effect: the Russian Federation has accumulated stocks of those brands of fuel that fell under sanctions. Mainly, the Ministry of Defense took care of the creation of reserves, the interlocutor in Roscosmos specified.

“We have accumulated the main rocket fuel, asymmetric dimethylhydrazine, on which the first stages of the Protons and a number of other rockets operate, for a decade ahead, so there is no shortage,” assured Ivan Moiseev, scientific director of the Space Policy Institute. - But with especially pure hydrazines, such as amidol, there are problems. Therefore, Roskosmos resolved this issue promptly.

A substance with a very simple formula and a very complicated history, in which there were ups (in the literal sense of the word) and downs (fortunately, mostly figuratively). This is hydrazine - H 2 N-NH 2.

History with backstory

The fact that hydrazine was discovered in the very late XIX century, no doubt. In Mendeleev's Fundamentals of Chemistry, as well as in Michele Giua's History of Chemistry, Theodor Curtius (1857-1928), a well-known chemist in his time, a professor in Kiel and Heidelberg, is named as the discoverer of hydrazine.

However, in French books on the history of chemistry, it is stated that pure anhydrous hydrazine was obtained only seven years after the experiments of Curtius, in 1894, by the French chemist Lobre de Brin. Curtius received only hydrazine sulfate - a salt of the composition N 2 H 4 -H 2 SO 4.

How it is

The new substance did not look too attractive. A colorless rather viscous liquid, fuming in air, with the smell of ammonia, not very resistant to oxidizing agents (prone to self-ignition) and hygroscopic. But hydrazine had properties that interested chemists. For example, it turned out to be a reducing agent, and a very active one at that. The oxides of many metals—iron, chromium, copper—reduced so rapidly upon contact with it that the excess of hydrazine ignited and burned with a violet flame.

Later it was found that under the action of these oxides, the catalytic decomposition of hydrazine into gaseous nitrogen and ammonia occurs. Thus, it proved to be suitable as a rocket fuel. But from this point of view, hydrazine became interested many years later. In the meantime, it was studied as a rather peculiar chemical phenomenon.

Heat is released during the combustion of hydrazine relatively little—much less than in the combustion of hydrocarbons. Hydrazine hydrate in this sense is even worse. But both of them burn well at low oxidant costs (the latter can be air and oxygen, hydrogen peroxide, nitric acid and fluorine; in addition, as we already know, hydrazine can create jet thrust and without the help of an oxidation reaction, decomposing on catalysts). This circumstance, as well as a large amount of gases formed during combustion, made hydrazine and its derivatives indispensable substances for rocket ranges.

Macro and micro

The engine of the second stage of the Cosmos rockets, through which in 1962-1967. about 200 have been launched into space orbits artificial satellites Earth, was a liquid-propellant jet engine RD-119. The fuel for it was a substance designated in reference books by four letters: UDMH. They are deciphered as follows: asymmetric dimethylhydrazine. Another important hydrazine derivative for rocket technology! Its formula is: (CH 3) 2 NNH 2 .

Unlike anhydrous hydrazine and hydrazine hydrate, this substance easily, in any ratio, mixes not only with water, but also with petroleum products. UDMH is a component of many liquid rocket propellants. The well-known American fuel for LRE "Aerozine-50" is a mixture of hydrazine and UDMH.

UDMH does not differ much from hydrazine: the same state of aggregation, close chemical and physical properties, the same unpleasant smell.

One significant detail. Unsymmetrical dimethylhydrazine is a good solvent. Therefore, most of the known gasket materials swell in it, losing strength and density. The only exceptions are some special rubbers, polyethylene and, of course, "plastic platinum" - fluoroplast-4.

The limits of explosive concentrations for mixtures of UDMH with air are extremely wide: from 2 to 99% UDMH by volume. For this reason, it is better not to allow it to come into contact with air. But there are other reasons as well. First, it is oxidized by oxygen; secondly, it interacts with carbon dioxide contained in the air (in this case, solid salts are formed); thirdly, like hydrazine, UDMH absorbs moisture from the air. All three processes lead to deterioration of rather expensive UDMH. Therefore, this difficult liquid is recommended to be stored under a nitrogen “cushion”.

The above is about the most famous examples the use of hydrazine and its derivatives in rocket technology. However, it was, if you like, the result, the highest point of take-off. And less significant events preceded it.

Many people know the name of the German engineer and inventor Helmut Walter. Until the outbreak of World War II, he was the technical director of a small instrument-making firm, and by the end of the war he had become one of the most revered (and deeply classified) figures in science and technology in Nazi Germany. Like Wernher von Braun, he developed the "weapon of retaliation" on which the Nazis counted so much and which gave them almost nothing.

Walter's entire career is associated with concentrated solutions of hydrogen peroxide. He used them both in engines for a submarine of a new design, and in jet engine own design. Eighty percent hydrogen peroxide worked in this engine as an oxidizer, while a mixture of almost equal amounts served as fuel for it. methyl alcohol and hydrazine hydrate. Hydrazine hydrate in the composition of the fuel ensured its easy and trouble-free self-ignition.

Walther engines were installed on Messerschmitt Me-163 fighters and on the Natter manned projectile. The latter was intended to combat bomber aircraft. The primitive wooden structure of the aircraft carried a powerful charge of 24 solid propellant rockets. After the salvo, the pilot and the expensive engine escaped by parachute, and the Nutter self-destructed in the air.

Further tests (September 1944) the idea with the "Nutter" did not go. It did not affect the outcome of the war, as, indeed, other undertakings of Helmut Walter. However, work on the use of hydrazine and its derivatives as jet fuel was continued in different countries. In particular, the Bomark, Avangard, Thor-Able, and Nike-Ajax rockets were built in the United States shortly after the war, using a mixture of unsymmetrical dimethylhydrazine and kerosene. Later, UDMH was included in the fuel of the engines of the second stage of the rockets "Tor-Delta", "Torad-Delta", "Tor-Agena", "Torad-Agena". It was also part of the fuel of the first and second stages of powerful launch vehicles "Titan-M", "Titan-Ill". And in the jet engine of the French fighter-bomber "Mirage-111" UDMH is used as an activating additive to traditional fuel.

Modern space technology needs not only giant rocket engines of the first and second stages. Recently, more and more attention has been paid to the development of microjet engines, with the help of which ships and satellites move to open space in conditions of weightlessness - change orbits, maneuver. In these micromotors, hydrazine also plays an important role.

Under the conditions of orbital flight, one of the most important requirements for rocket fuel is the simplicity and reliability of its ignition (or the start of a spontaneous decomposition reaction with the release of gaseous products). From this point of view, hydrazine and its derivatives have no equal. They ignite very easily, and the decomposition of hydrazine into nitrogen and ammonia is possible both under the influence of heating and under the influence of catalysts. As a result, micromotors with hydrazine and its derivatives are manufactured in several countries.

But not only in space, not only for space technology, we need hydrazine. Today, many studies and books are devoted to the chemistry of hydrazine. Hundreds of thousands of derivatives have been obtained, and some of them turned out to be practically significant.

Many biologically active substances, hydrazine derivatives, are used in therapeutic practice. Known, in particular, a group of drugs for tuberculosis, in which operating principle isonicotinic acid hydrazide, a derivative of hydrazine. Other derivatives of it are used as a remedy for nervous depression.

And maleic acid hydrazide is a growth stimulant for potatoes, sugar beets, grapes, and tobacco.

Of course, not all hydrazine derivatives are applicable for such purposes. It has long been known that both hydrazine itself and its simplest derivatives used in rocket technology are toxic. Reports of toxicity of many hydrazine derivatives that appeared in the medical literature in last years, make us treat these substances with even greater vigilance and attention. However, they learned to defend themselves quite reliably from their harmfulness.

Highly efficient and reliable hydrazine-air and hydrazine-oxygen fuel cells, chemical power sources, have been developed and are already being used in some places. They worked, in particular, instead of batteries on board the Canadian single-seat research submarine Star.

When working in a fuel cell, only completely harmless water and nitrogen are formed from the relatively poisonous hydrazine (or hydrazine hydrate). Electric Energy is produced due to the reaction taking place at the anode:

Ecological safety is the main advantage of such current sources.

Hydrazine-air fuel cells have been successfully tested on a micro-motorcycle and an electric cargo vehicle that has reached speeds of more than 70 kilometers per hour.

In a word, hydrazine found its way both in space, and under water, and on earth.

The recent failure of the Dnepr rocket, a space launch vehicle converted from the R-36M UTTKh military rocket, has again aroused interest in rocket fuel.

V-2 ("V-2") formed the basis of all post-war rocket technology, both American and Soviet

The launch of 900 V-2 rockets required 12 thousand tons of liquid oxygen, 4 thousand tons of ethyl alcohol, 2 thousand tons of methanol, 500 tons of hydrogen peroxide and 1.5 thousand tons of explosives

Instead of alcohol, which Wernher von Braun used along with liquid oxygen, Korolev chose kerosene for his first rockets.

Neither gasoline, nor kerosene, nor diesel fuel ignites themselves when interacting with acid, and for military missiles, self-ignition is one of the key fuel requirements.

The S-4B rocket, the third stage of another brainchild of Wernher von Braun - the most powerful American Saturn V launch vehicle. The latter has 13 successful launches (from 1967 to 1973). It was with her help that a man set foot on the moon

Liquid propellant rocket engines (LRE) are very advanced machines, and their characteristics are 90% or even more determined by the fuel used. The efficiency of the fuel depends on the composition and stored energy. The ideal fuel should consist of light elements - from the very beginning of the periodic table, giving maximum energy during oxidation. But these are not all the requirements for fuel - it must also be compatible with structural materials, stable during storage and, if possible, inexpensive. But a rocket is not only an engine, but also tanks of a limited volume: in order to take on board more fuel, its density must be higher. In addition to fuel, the rocket carries with it an oxidizer.

The ideal oxidizing agent from the point of view of chemistry is liquid oxygen. But a rocket is not limited to chemistry alone, it is a design in which everything is interconnected. Wernher von Braun chose alcohol and liquid oxygen for the V-2, and the range of the rocket was 270 km. But if its engine ran on nitric acid and diesel fuel, then the range would increase by a quarter, because two tons more of such fuel is placed in the same tanks!

Rocket fuel is a storehouse of chemical energy in a compact form. Fuel is better, the more energy it stores. Therefore, substances that are good for rocket fuel are always extremely chemically active, constantly trying to release latent energy, corroding, burning and destroying everything around. All rocket oxidizers are either explosive, poisonous, or unstable. Liquid oxygen is the only exception, and that only because nature has become accustomed to 20% free oxygen in the atmosphere. But even liquid oxygen requires respect.

keep forever

Ballistic missiles R-1, R-2 and R-5, created under the leadership of Sergei Korolev, not only showed the promise of this type of weapon, but also made it clear that liquid oxygen is not very suitable for combat missiles. Despite the fact that the R-5M was the first missile with a nuclear warhead, and in 1955 there was even a real test with a detonation of a nuclear charge, the military did not like the fact that the rocket had to be refueled immediately before launch. It was necessary to replace liquid oxygen, a full-fledged replacement, such that it would not freeze even in Siberian frosts, and would not boil away in the Karakum heat: that is, with a temperature range from -55 degrees to +55 degrees Celsius. True, no problems were expected with boiling in the tanks, since the pressure in the tank is increased, and with increased pressure, the boiling point is higher. But oxygen under no pressure will be liquid at a temperature above the critical one, that is, -113 degrees Celsius. And there are no such frosts even in Antarctica.

Nitric acid HNO3 is another obvious oxidant for liquid propellant rocket engines, and its use in rocketry went hand in hand with liquid oxygen. Salts of nitric acid - nitrates, especially potassium nitrate - have been used for many centuries as an oxidizing agent for the very first rocket fuel - black powder.

The nitric acid molecule contains only one nitrogen atom and a “half” of a water molecule as ballast, while two and a half oxygen atoms can be used to oxidize fuel. But nitric acid is a very "cunning" substance, so strange that it continuously reacts with itself - hydrogen atoms are split off from one acid molecule and cling to neighboring ones, forming fragile, but extremely chemically active aggregates. Because of this, various kinds of impurities are necessarily formed in nitric acid.

In addition, nitric acid obviously does not meet the requirements for compatibility with structural materials - it is specially necessary to select metal for tanks, pipes, and LRE chambers for it. Nevertheless, "nitrogen" became a popular oxidizer as early as the 1930s - it is cheap, produced in large quantities, stable enough to cool the engine chamber, fire and explosion-proof. Its density is noticeably greater than that of liquid oxygen, but its main advantage compared to liquid oxygen is that it does not boil away, does not require thermal insulation, and can be stored in a suitable container indefinitely. But where can I get it, a suitable container?

The entire 1930s and 1940s were spent in search of suitable containers for nitric acid. But even the most resistant grades of stainless steel were slowly destroyed by concentrated nitrogen, as a result, a thick greenish “kissel” formed at the bottom of the tank, a mixture of metal salts, which, of course, cannot be fed into a rocket engine - it will instantly clog and explode.

To reduce the corrosive activity of nitric acid, they began to add to it various substances, trying, often by trial and error, to find a combination that, on the one hand, would not spoil the oxidizer, on the other hand, would make it more convenient to use. But a successful additive was found only in the late 1950s by American chemists - it turned out that only 0.5% hydrofluoric (hydrofluoric) acid reduces the corrosion rate of stainless steel tenfold! Soviet chemists delayed this discovery by ten or fifteen years.

Secret additives

Nevertheless, the first BI-1 rocket interceptor in the USSR used nitric acid and kerosene. Tanks and pipes had to be made of monel metal, an alloy of nickel and copper. This alloy was obtained in a “natural” way from some polymetallic ores, therefore it was a popular structural material in the second third of the 20th century. About him appearance can be judged by the metal rubles - they are made of almost "rocket" alloy. During the war, however, there was a shortage not only of copper and nickel, but also of stainless steel. I had to use the usual, covered with chrome for protection. But a thin layer was quickly eaten away by acid, so after each engine start, the remnants of the fuel mixture had to be removed from the combustion chamber with scrapers - the technicians involuntarily inhaled toxic fumes. One of the pioneers of rocket technology, Boris Chertok, once nearly died in a BI-1 engine explosion on a stand; he described this episode in his wonderful book “Rockets and People”.

In addition to additives that reduce the aggressiveness of nitric acid, they tried to add various substances to it in order to increase its effectiveness as an oxidizing agent. The most effective substance was nitrogen dioxide, another "strange" compound. Usually - a brown gas, with a sharp unpleasant odor, but if it is slightly cooled, it liquefies and two molecules of dioxide stick together into one. Therefore, the compound is often called nitrogen tetroxide, or nitrogen tetroxide - AT. At atmospheric pressure AT boils at room temperature (+21 degrees), and freezes at -11 degrees. The closer to the freezing point, the paler the color of the compound, becoming in the end pale yellow, and in the solid state - almost colorless. This is because the gas consists mainly of NO2 molecules, the liquid consists of a mixture of NO2 and N2O4 dimers, and only colorless dimers remain in the solid.

The addition of AT to nitric acid increases the efficiency of the oxidizer for many reasons at once - AT contains less "ballast", binds water that enters the oxidizer, which reduces the corrosiveness of the acid. The most interesting thing is that with the dissolution of AT in AA, the density of the solution first increases and reaches a maximum at 14% of the dissolved AT. It was this version of the composition that the American rocket scientists chose for their combat missiles. Ours, on the other hand, sought to improve the performance of engines at any cost, therefore, in the AK-20 and AK-27 oxidizers, there were 20% and 27%, respectively, of dissolved nitrogen tetroxide. The first oxidizer was used in anti-aircraft missiles, and the second - in ballistic missiles. The Yangel Design Bureau created the R-12 medium-range missile, which used the AK-27 and a special grade of kerosene TM-185.

Lighters

In parallel with the search for the best oxidizer, there was a search for the optimal fuel. The military would be most satisfied with the product of the distillation of oil, but other substances, if they were produced in sufficient quantities and were inexpensive, could also be used. There was only one problem - neither gasoline, nor kerosene, nor diesel fuel ignite themselves upon contact with nitric acid, and for military missiles self-ignition is one of the key fuel requirements. Although our first R-7 intercontinental missile used a kerosene-liquid oxygen pair, it became clear that pyrotechnic ignition was inconvenient for combat missiles. When preparing the rocket for launch, it was necessary to manually insert into each nozzle (and the R-7 has no less than 32-20 main chambers and 12 helmsmen) a wooden cross with an incendiary bomb, connect all the electrical wires that ignite the bombs, and do many more different preparatory operations.

In the R-12, these shortcomings were taken into account, and ignition was provided by starting fuel, which spontaneously ignited upon contact with nitric acid. Its composition was found by German rocket scientists during the Second World War, and it was called "Tonka-250". Our rocket scientists renamed it in accordance with GOSTs in TG-02. Now the rocket could stand refueled for several weeks, and this was a great success, since it could be launched within a couple of hours instead of three days for the R-7. But three components are a lot for a combat missile, and for use as the main fuel, the TG-02 was suitable only for anti-aircraft missiles; for ballistic missiles long range something more efficient was needed.

Hyperholics

Chemists called the pairs of substances that spontaneously ignite on contact "hypergolic", that is, in an approximate translation from Greek, having an excessive affinity for each other. They knew that substances that contain, in addition to carbon and hydrogen, nitrogen are best ignited with nitric acid. But “better” is how much?

Self-ignition delay is a key property for chemical vapors that we want to burn in a rocket engine. Imagine - they turned on the supply, fuel and oxidizer accumulate in the chamber, but there is no ignition! But when it finally happens, a powerful explosion blows the LRE chamber to pieces. To determine the self-ignition delay, various researchers built stands of various complexity - from two pipettes, synchronously squeezing out a drop of oxidizer and fuel, to small rocket engines without a nozzle - a nozzle head and a short cylindrical pipe. All the same, explosions were heard very often, acting on nerves, breaking windows and damaging sensors.

Very quickly, the "ideal hypergol" was discovered - hydrazine, an old acquaintance of chemists. This substance has the formula N2H4 physical properties very similar to water - the density is several percent higher, the freezing point is +1.5 degrees, the boiling point is +113 degrees, the viscosity and everything else is like that of water, but here's the smell ...

Hydrazine was obtained for the first time in its pure form at the end of the 19th century, and in the composition of rocket fuel it was first used by the Germans in 1933, but as a relatively small additive for self-ignition. As an independent fuel, hydrazine was expensive, its production was not enough, but, most importantly, the military was not satisfied with its freezing temperature - higher than that of water! A "hydrazine antifreeze" was needed, and the search for it was continuous. Very good hydrazine! Wernher von Braun replaced the alcohol in the Redstone rocket with Hydyne, a mixture of 60% hydrazine and 40% alcohol, to launch the first US satellite, the Explorer. Such fuel improved the energy of the first stage, but in order to achieve the necessary characteristics, the tanks had to be lengthened.

Hydrazine, like ammonia NH3, consists only of nitrogen and hydrogen. But if energy is released during the formation of ammonia from the elements, then energy is absorbed during the formation of hydrazine - which is why the direct synthesis of hydrazine is impossible. On the other hand, the energy absorbed during formation will then be released during the combustion of hydrazine in the LRE and will go to increase the specific impulse - the main indicator of engine perfection. A pair of oxygen-kerosene makes it possible to obtain a specific thrust for the first stage engines in the region of 300 seconds. Replacing liquid oxygen with nitric acid worsens this value to 220 seconds. This deterioration requires an increase starting weight almost twice. If we replace kerosene with hydrazine, most of this deterioration can be "played back". But the military needed to keep the fuel from freezing, and they demanded an alternative.

Parted ways

And then the paths of our and American chemists diverged! In the USSR, chemists came up with a method for producing unsymmetrical dimethylhydrazine, while the Americans preferred a simpler process in which monomethylhydrazine was obtained. Both of these liquids, despite their extreme toxicity, suited both designers and the military. Rocketeers were no strangers to accuracy when handling dangerous substances, but still the new substances were so toxic that an ordinary gas mask could not cope with cleaning the air from their vapors! It was necessary either to use an insulating gas mask, or a special cartridge that oxidized toxic fumes to a safe state. On the other hand, methylated hydrazine derivatives were less explosive, absorbed less water vapor, and were thermally more stable. But the boiling point and density are lower compared to hydrazine.

So the search continued. The Americans at one time very widely used "Aerozine-50" - a mixture of hydrazine and UDMH, which was the result of the invention of a technological process in which they were obtained simultaneously. Later, this method was superseded by more advanced ones, but Aerozine-50 managed to spread, and both Titan-2 ballistic missiles and the Apollo spacecraft flew on it. The Saturn V rocket propelled it to the Moon on liquid hydrogen and oxygen, but the Apollo's own engine, which needed to be fired several times during a week-long flight, had to use a self-igniting long-storable propellant.

Greenhouse conditions

But further with ballistic missiles an amazing metamorphosis took place - they hid in the mines to protect themselves from the first blow of the enemy. At the same time, frost resistance was no longer required, since the air in the mine was heated in winter and cooled in summer! Fuel could be selected without taking into account its frost resistance. And immediately, the engine engineers abandoned nitric acid, switching to pure nitrogen tetroxide. The one that boils at room temperature! After all, the pressure in the tank is increased, and with increased pressure and boiling point, we are much less worried. But now the corrosion of tanks and pipelines has decreased so much that it has become possible to keep the rocket refueled throughout the entire period of combat duty! The first rocket that could stand refueled for 10 years in a row was the UR-100 designed by the Chelomey Design Bureau. Almost simultaneously with it, a much heavier P-36 from Yangel appeared. Its current descendant, the latest modification of the R-36M2, except for tanks, has little in common with the original missile.

According to the energy characteristics of the pair "oxygen - kerosene" and "nitrogen tetroxide - UDMH" are very close. But the first pair is good for space launch vehicles, and the second one is good for silo-based ICBMs. To work with such toxic substances, a special technology has been developed - rocket ampulization after refueling. Its meaning is clear from the name: all lines are irreversibly blocked to avoid even the slightest leaks. It was first used on missiles for submarines, which also used such fuel.

solid fuel

American rocket scientists preferred solid fuel for combat missiles. It had slightly worse characteristics, but the rocket required much less preparatory operations during launch. Ours also tried to use solid-propellant rockets, but the last stage still had to be made liquid in order to compensate for the dispersion of solid-propellant engines, which cannot be controlled in the same way as liquid ones. And later, when missiles with several warheads appeared, the task of "breeding" them at targets fell on the last liquid stage. So the AT-NDMG couple did not remain without work. It does not remain now: engines run on this fuel spaceship Soyuz, the International Space Station and many other vehicles.

(st. conv.)

Hydrazine(diamide) H 2 N-NH 2 is a colorless, highly hygroscopic liquid with an unpleasant odor.

The N 2 H 4 molecule consists of two NH 2 groups rotated relative to each other, which determines the polarity of the hydrazine molecule, μ = 0.62 10 −29 C m. Miscible in any ratio with water, liquid ammonia, ethanol; It is poorly soluble in non-polar solvents. In terms of stability, hydrazine is significantly inferior to ammonia, since the N–N bond is not very strong.

Properties

Due to the presence of two lone pairs of electrons at nitrogen atoms, hydrazine is capable of attaching one or two hydrogen ions. When one proton is attached, hydrazinium compounds with a charge of 1+ are obtained, two protons - hydrazinium 2+, containing, respectively, N 2 H 5 + and N 2 H 6 2+ ions. Aqueous solutions of hydrazine have basic properties, but its basicity is much less than that of ammonia:

N 2 H 4 + H 2 O → + + OH - K b = 3.0 x 10 -6

(for ammonia K b = 1.78 x 10 −5) The protonation of the second lone pair of electrons is even more difficult:

H 2 O → 2+ + OH - K b = 8.4 x 10 -16

Hydrazine salts are known - N 2 H 5 Cl chloride, N 2 H 6 SO 4 sulfate, etc. Sometimes their formulas are written N 2 H 4 HCl, N 2 H 4 H 2 SO 4, etc. and are called hydrazine hydrochloride, hydrazine sulfate, etc. Most of these salts are soluble in water.

NH 3 + NaClO NH 2 Cl + NaOH NH 2 Cl + NH 3 N 2 H 4 HCl,

the reaction is carried out at a temperature of 160 °C and a pressure of 2.5-3.0 MPa.

The synthesis of hydrazine by oxidation of urea with hypochlorite is similar in mechanism to the synthesis of amines from amides according to Hoffmann:

H 2 NCONH 2 + NaOCl + 2 NaOH N 2 H 4 + NaCl + Na 2 CO 3,

the reaction is carried out at a temperature of ~100 °C and atmospheric pressure.

Hydrazine as fuel

Hydrazine and its derivatives such as UDMH and Aerozine are widely used as rocket propellants. They can be used both in tandem with an oxidizer and as a single-component fuel - in this case, the working fluid of the engine is the decomposition products on the catalyst. The latter is convenient for low-power engines.
During World War II, hydrazine was used in Germany on jet fighters"Messerschmitt Me-16Z".

Theoretical characteristics of various types of rocket fuel formed by hydrazine with various oxidizers.

Hydrazine in fuel cells

Hydrazine is widely used as a fuel in hydrazine-air low-temperature fuel cells.

Hydrazine in the production of explosives

Hydrazine nitrate and perchlorate are used as very powerful explosives - different varieties of astrolite. They have high speed detonation. A liquid mixture of hydrazine and ammonium nitrate is used as a powerful zero oxygen balance explosive.

Hydrazine in space

The main reason for the destruction of the American spy satellite USA-193 / NROL-21, launched in 2006 and uncontrollably descending from orbit, was the presence of about half a ton of hydrazine on board (as well as possible access to technology as a result of falling debris of the satellite to the ground). The satellite was shot down on February 21, 2008 by a missile launched from the US Navy cruiser Lake Erie at 06:26 Moscow time.

Toxicity

Hydrazine and its derivatives are extremely toxic compounds in relation to various types animal and plant organisms. Dilute solutions of hydrazine sulfate have a detrimental effect on seeds, algae, unicellular and protozoa. In mammals, hydrazine causes convulsions. Hydrazine and its derivatives can penetrate into the animal body in any way: by inhalation of product vapors, through the skin, through the digestive tract. For humans, the degree of toxicity of hydrazine has not been determined. According to S. Krop's calculations, 0.4 mg/l should be considered a dangerous concentration. Ch. Comstock and employees believe that the maximum allowable concentration should not exceed 0.006 mg/l. According to more recent American data, this concentration was reduced to 0.0013 mg/l after an 8-hour exposure. It is important to note that the threshold of olfactory sensation of hydrazine in humans significantly exceeds the indicated numbers and is equal to 0.014-0.030 mg/l. Significant in this regard is the fact that the characteristic smell of a number of hydrazine derivatives is felt only in the first minutes of contact with them. In the future, due to the adaptation of the olfactory organs, this sensation disappears, and a person, without noticing it, can stay in a contaminated atmosphere for a long time, containing toxic concentrations of the named substance.

Clinical picture of acute injury by hydrazine and its derivatives

The clinical picture of acute inhalation poisoning is characterized by initial symptoms of irritation of the upper respiratory tract. Patients complain of dryness and perspiration in the pharynx, cough, pain and soreness behind the sternum. Sometimes there is also irritation of the mucous membrane of the eyes, accompanied by a feeling of pain in the eyes and lacrimation. Headache, dizziness, general weakness are noted. Nausea and vomiting should be considered characteristic signs of poisoning. Vomiting is cerebral in origin, since it occurs immediately after exposure to a toxic agent, is not associated with food intake, decreases or disappears after general detoxification measures. This is confirmed by the corresponding experimental studies , in which the reaction of isolated intestinal loops to poison was absent. Clinically, during this period, hyperemia of the pharynx develops, breathing becomes more frequent, a box shade of percussion sound, harsh breathing and scattered dry rales appear above the lungs. The phenomena of hypoxia develop, in particular cyanosis. A spasm of the glottis with the development of suffocation syndrome is described. Body temperature rises. Arterial pressure in the initial stage of intoxication increases slightly, then progressively decreases. At high doses of poison, collapse is possible. The heart rate also has a similar two-phase character of changes: at first, the pulse quickens, then it slows down. Atrioventricular conduction, according to R. Walton (1952) and R. Pens (1963), worsens before the development of a complete atrioventricular block. In cases of very severe poisoning, contractility of the heart muscle suffers, and ventricular flutter may occur in the terminal stage. Possible loss of consciousness, the occurrence of clonic and tonic convulsions. In case of poisoning, there may be deviations from other systems. The liver undergoes significant changes. It increases in size, its functional insufficiency develops, manifested by a sharp hypoglycemia, a decrease in glucose utilization, a decrease in glycogen reserves, an inability to produce glycogen from fats and proteins, and a violation of the antitoxic and deaminating function. Hyperfermentemia is observed: transaminase activity of blood serum increases, as well as the activity of dehydrogenases of lactic, malic, glutamic and isocitric acids, associated with the release of these enzymes from liver cells damaged by poison. F.Underhill (1908) was the first to note the high regenerative capacity of the liver affected by hydrazine, its compensatory capabilities, and the "adaptation" of the organ to the poison. He showed that hydrazine damage to the liver is reversible in some cases. The kidneys are rarely affected by hydrazine poisoning. Protein and red blood cells appear in the urine. There are reports of the possible occurrence of focal and intersignal nephritis, and a case of kidney infarction is also described. The blood undergoes a number of changes. Registered neutrophilic leukocytosis, relative lymphopenia, eosinopenia. In the acute period of poisoning, the number of erythrocytes and hemoglobin in victims increases, which, apparently, can be explained by the irritating effect of the poisonous substance on the bone marrow. Subsequently, the amount of hemoglobin and red blood cells decreases. This is probably largely due to the onset of hemolysis, which is a rather characteristic sign of poisoning by the named group of compounds, especially monomethylhydrazine. globulin”), which allowed the author to classify this substance as an agent of relative fibrinolytic action. If hydrazine gets into the eyes, conjunctivitis, swelling, and often suppuration develop. Upon contact of the substance with the cornea, a soluble proteinate may form, violating its integrity, which creates conditions for the penetration of the poison into the internal environment of the eye. The compounds of the hydrazine group act on the skin, causing various kinds of dermatitis in victims, and if large quantities are ingested, superficial chemical burns. Visible the clinic of an acute hydrazine lesion manifests itself quite quickly. Irritation symptoms are noted shortly after exposure to the substance. The phenomena of general intoxication - after hours. In case of poisoning with large doses of poison, the terms are reduced. Depending on the conditions and nature of the action of the poison, the severity of the clinical picture of intoxication may be different. Mild poisoning is limited to irritation of the mucous membranes of the eyes and upper respiratory tract, headache, dizziness, nausea, general weakness, pulse lability and blood pressure. The greatest intensity of the disorder occurs within 1 day of poisoning. In the following days, they noticeably subside. The state of health of the victims is fully restored by the end of the week. With moderate poisoning, these symptoms are more pronounced. Characterized by vomiting, often multiple. A short-term loss of consciousness is possible. There is retardation. Frequent acute toxic bronchitis and pneumonia. Frequent toxic damage to the liver up to the development of toxic hepatitis. The duration of the course of the lesion is 2-3 weeks, with pneumonia and toxic hepatitis, the lesion is delayed for a longer time.

Literature

• Akhmetov N.S. "General and inorganic chemistry" M.: Higher School, 2001
• Karapetyants M.Kh. Drakin S.I. General and inorganic chemistry. M.: Chemistry 1994

The Center for the Operation of Ground-Based Space Infrastructure Facilities (FSUE TsENKI) has completed the construction of a plant for the production of hydrazine, a fuel used to refuel rocket and spacecraft engines.

The plant for the production of hydrazine in Russia was built within the framework of the Federal Target Program "Development, restoration and organization of production of strategic, scarce and import-substituting materials", - said Rano Juraeva, acting. General Director of TsENKI. - It is located in the Nizhny Novgorod region, the design capacity is 15 tons per year. At present, complex tests of the equipment are underway.

Hydrazine is used to refuel spacecraft and upper stages - this explains the low volume of production.

The production of hydrazine and heptyl (unsymmetrical dimethylhydrazine) in Russia was curtailed in the 1990s. Since then, hydrazine has been purchased from abroad, mainly from Germany. In 2014, after the aggravation of relations with the countries of the Western bloc, the supply of hydrazine to the Russian Federation ceased, as this species fuel is used, among other things, for the implementation of military programs. In October 2014, the sanctions were partially relaxed: the Council of the European Union allowed the supply of hydrazine and heptyl to Russia in cases where the fuel is purchased for the implementation of joint programs with the European Space Agency or for the launch of European spacecraft. The sellers were instructed to ensure that Russian companies buy exactly the right amount of fuel for a specific project.

According to representatives of Roskosmos, the fuel embargo had no effect on space programs. More precisely, it has not yet had time to have an effect: the Russian Federation has accumulated stocks of those brands of fuel that fell under sanctions. Mainly, the Ministry of Defense took care of the creation of reserves, the interlocutor in Roscosmos specified.

We have accumulated the main rocket fuel - asymmetric dimethylhydrazine, on which the first stages of the Protons and a number of other rockets work, for a decade ahead, so there is no shortage, - assured Ivan Moiseev, scientific director of the Space Policy Institute. - But with especially pure hydrazines, such as amidol, there are problems. Therefore, Roskosmos resolved this issue promptly.

Overlays European countries and the US sanctions have adjusted the policy of Roskosmos in a number of ways. The most sensitive here was the ban on the supply of electronic component base (ECB) to the Russian Federation.

The supply of dual-use electronic components (categories: military - for use in military systems, space - radiation-resistant components) is regulated by international arms trade regulations (ITAR) and requires export licenses for export from the US and EU. The US Commercial Department's Bureau of Industry and Security (BIS) suspended licenses last year, preventing suppliers from selling to Russian space equipment manufacturers the electronic components previously used in Russian satellites. As a result, a number of projects fell under forced redesign, including