2 N H 3 + N a O C l ⟶ N 2 H 4 + N a C l + H 2 O (\displaystyle (\mathsf (2NH_(3)+NaOCl\longrightarrow N_(2)H_(4)+NaCl+H_( 2)O)))

• Halogens (chlorine, iodine) form dangerous explosives with ammonia - nitrogen halides (nitrogen chloride, nitrogen iodide).

• With haloalkanes, ammonia enters into a nucleophilic addition reaction, forming a substituted ammonium ion (a method for obtaining amines):

• With carboxylic acids, their anhydrides, acid halides, esters and other derivatives gives amides. With aldehydes and ketones - Schiff bases, which can be reduced to the corresponding amines (reductive amination).

Story

Ammonia was first isolated in its pure form by J. Priestley in 1774, who called it "alkaline air" (English alkaline air) . Eleven years later, in 1785, K. Berthollet established the exact chemical composition of ammonia. Since that time, research has begun in the world on the production of ammonia from nitrogen and hydrogen. Ammonia was very necessary for the synthesis of nitrogen compounds, since their production from Chilean saltpeter was limited by the gradual depletion of the latter's reserves. The problem of decreasing stocks of saltpeter became more acute by the end of the 19th century. Only at the beginning of the 20th century was it possible to invent a process for the synthesis of ammonia suitable for industry. This was carried out by F. Haber, who began working on this problem in 1904 and by 1909 had created a small contact apparatus in which he used increased pressure (in accordance with the Le Chatelier principle) and an osmium catalyst. On July 2, 1909, Haber arranged tests of the apparatus in the presence of K. Bosch and A. Mittash, both from the Baden Aniline and Soda Plant (BASF), and received ammonia. By 1911, C. Bosch created a large-scale version of the apparatus for BASF, and then it was built and on September 9, 1913, the world's first ammonia synthesis plant was put into operation, which was located in Oppau (now a district within the city of Ludwigshafen am Rhein) and owned by BASF. In 1918, F. Haber won the Nobel Prize in Chemistry "for the synthesis of ammonia from its constituent elements." In Russia and the USSR, the first batch of synthetic ammonia was obtained in 1928 at the Chernorechensky chemical plant.

origin of name

Ammonia (in European languages, its name sounds like “ammoniac”) owes its name to the Ammon oasis in North Africa, located at the crossroads of caravan routes. In hot climates, urea (NH 2) 2 CO contained in animal waste decomposes especially quickly. One of the degradation products is ammonia. According to other sources, ammonia got its name from the ancient Egyptian word amonian. So called people worshiping the god Amun. During their ritual rites, they sniffed ammonia NH 4 Cl, which, when heated, evaporates ammonia.

Liquid ammonia

Liquid ammonia, although to a small extent, dissociates into ions (autoprotolysis), which shows its similarity with water:

The self-ionization constant of liquid ammonia at −50 °C is approximately 10 −33 (mol/l)².

The metal amides resulting from the reaction with ammonia contain the negative ion NH 2 − , which is also formed during the self-ionization of ammonia. Thus, metal amides are analogues of hydroxides. The reaction rate increases when going from Li to Cs. The reaction is greatly accelerated in the presence of even small impurities of H 2 O.

Metal-ammonia solutions have metallic electrical conductivity; in them, metal atoms decay into positive ions and solvated electrons surrounded by NH 3 molecules. Metal-ammonia solutions containing free electrons are the strongest reducing agents.

complexation

Due to their electron-donating properties, NH 3 molecules can enter complex compounds as a ligand. Thus, the introduction of excess ammonia into solutions of salts of d-metals leads to the formation of their amino complexes:

Complexation is usually accompanied by a change in the color of the solution. So, in the first reaction, the blue color (CuSO 4) turns into dark blue (color of the complex), and in the second reaction, the color changes from green (Ni (NO 3) 2) to blue-violet. The strongest complexes with NH 3 form chromium and cobalt in the +3 oxidation state.

Biological role

Ammonia is an important source of nitrogen for living organisms. Despite the high content of free nitrogen in the atmosphere (more than 75%), very few living beings are able to use the free, neutral diatomic nitrogen of the atmosphere, N 2 gas. Therefore, in order to include atmospheric nitrogen in the biological cycle, in particular in the synthesis of amino acids and nucleotides, a process called “nitrogen fixation” is necessary. Some plants depend on the availability of ammonia and other nitrogenous residues released into the soil by the decaying organic matter of other plants and animals. Some others, such as nitrogen-fixing legumes, take advantage of symbiosis with nitrogen-fixing bacteria (rhizobia), which are able to form ammonia from atmospheric nitrogen.

In some organisms, ammonia is produced from atmospheric nitrogen by enzymes called nitrogenases. This process is called nitrogen fixation. Although it is unlikely that biomimetic methods will ever be invented that can compete in productivity with chemical methods for the production of ammonia from nitrogen, nevertheless, scientists are making great efforts to better understand the mechanisms of biological nitrogen fixation. Scientific interest in this problem is partly motivated by the unusual structure of the active catalytic site of the nitrogen-fixing enzyme (nitrogenase), which contains an unusual bimetallic molecular ensemble Fe 7 MoS 9 .

Ammonia is also an end product of amino acid metabolism, namely the product of their deamination catalyzed by enzymes such as glutamate dehydrogenase. Excretion of unchanged ammonia is the usual route for ammonia detoxification in aquatic creatures (fish, aquatic invertebrates, and to some extent amphibians). In mammals, including humans, ammonia is usually rapidly converted to urea, which is much less toxic and, in particular, less alkaline and less reactive as a reducing agent. Urea is the main component of the dry residue of urine. Most birds, reptiles, insects, arachnids, however, excrete not urea, but uric acid as the main nitrogenous residue.

Ammonia also plays an important role in both normal and pathological animal physiology. Ammonia is produced during normal amino acid metabolism, but is highly toxic at high concentrations. Animal liver converts ammonia to urea through a series of sequential reactions known as the urea cycle. Dysfunction of the liver, such as that seen in cirrhosis of the liver, can impair the ability of the liver to detoxify ammonia and form urea from it, and as a result, increase the level of ammonia in the blood, a condition called hyperammonemia. A similar result - an increase in the level of free ammonia in the blood and the development of hyperammonemia - leads to the presence of congenital genetic defects in the enzymes of the urea cycle, such as, for example, ornithine carbamyl transferase. The same result can be caused by a violation of the excretory function of the kidneys in severe renal failure and uremia: due to a delay in the release of urea, its level in the blood increases so much that the “urea cycle” begins to work “in the opposite direction” - excess urea is hydrolyzed back by the kidneys into ammonia and carbon dioxide gas, and as a result, the level of ammonia in the blood increases. Hyperammonemia contributes to impaired consciousness and the development of soporous and comatose conditions in hepatic encephalopathy and uremia, as well as to the development of neurological disorders often observed in patients with congenital defects in urea cycle enzymes or with organic aciduria.

Less pronounced, but clinically significant, hyperammonemia can be observed in any processes in which increased protein catabolism is observed, for example, with extensive burns, tissue compression or crush syndrome, extensive purulent-necrotic processes, gangrene of the extremities, sepsis, etc., and also with some endocrine disorders, such as diabetes mellitus, severe thyrotoxicosis. Especially high is the likelihood of hyperammonemia in these pathological conditions in cases where the pathological condition, in addition to increased protein catabolism, also causes a pronounced violation of the detoxifying function of the liver or the excretory function of the kidneys.

Ammonia is important for maintaining a normal acid-base balance in the blood. After the formation of ammonia from glutamine, alpha-ketoglutarate can be further broken down to form two bicarbonate molecules, which can then be used as a buffer to neutralize dietary acids. The ammonia obtained from glutamine is then excreted in the urine (both directly and in the form of urea), which, given the formation of two molecules of bicarbonate from ketoglutarate, leads in total to a loss of acids and a shift in blood pH to the alkaline side. In addition, ammonia can diffuse through the renal tubules, combine with the hydrogen ion and be excreted together with it (NH 3 + H + => NH 4 +), and thereby further contribute to the removal of acids from the body.

Ammonia and ammonium ions are toxic by-products of animal metabolism. In fish and aquatic invertebrates, ammonia is released directly into the water. In mammals (including aquatic mammals), amphibians, and sharks, ammonia is converted to urea in the urea cycle because urea is much less toxic, less chemically reactive, and can be more efficiently "stored" in the body until it can be excreted. In birds and reptiles (reptiles), the ammonia formed during metabolism is converted into uric acid, which is a solid residue and can be isolated with minimal loss of water.

Physiological action

According to the physiological effect on the body, it belongs to the group of substances with an asphyxiant and neurotropic effect, which, when inhaled, can cause toxic pulmonary edema and severe damage to the nervous system. Ammonia has both local and resorptive effects.

Ammonia vapor strongly irritates the mucous membranes of the eyes and respiratory organs, as well as the skin. This is a person and perceives as a pungent smell. Ammonia vapors cause profuse lacrimation, pain in the eyes, chemical burns of the conjunctiva and cornea, loss of vision, coughing fits, redness and itching of the skin. When liquefied ammonia and its solutions come into contact with the skin, a burning sensation occurs, a chemical burn with blisters and ulcerations is possible. In addition, liquefied ammonia absorbs heat during evaporation, and frostbite of varying degrees occurs when it comes into contact with the skin. The smell of ammonia is felt at a concentration of 37 mg/m³.

Application

Ammonia is one of the most important products of the chemical industry, its annual world production reaches 150 million tons. It is mainly used for the production of nitrogen fertilizers (ammonium nitrate and sulfate, urea), explosives and polymers, nitric acid, soda (ammonia method) and other chemical products. Liquid ammonia is used as a solvent.

Ammonia. Physical and chemical properties Chemical properties Due to the presence of a lone electron pair, ammonia acts as a complexing agent in many reactions. It attaches a proton, forming an ammonium ion. An aqueous solution of ammonia (“ammonia”) has a slightly alkaline environment due to the process: O > +; Ko=1, 8?10 -5 . (16) Interacting with acids, gives the corresponding ammonium salts: 2(O) + > (+ O. (17) Ammonia is also a very weak acid, capable of forming salts with metals - amides. When heated, ammonia exhibits reducing properties. So, it burns in an oxygen atmosphere, forming water and nitrogen. Oxidation of ammonia with air on a platinum catalyst gives nitrogen oxides, which is used by industry to produce nitric acid: 4 + 54NO + 6O. (18) The use of ammonia Cl is based on the reducing ability to clean the metal surface from oxides during their soldering: 3CuO + 2Cl > 3Cu + 3O + 2HCl +. (19) With haloalkanes, ammonia enters into a nucleophilic addition reaction, forming a substituted ammonium ion (a method for obtaining amines): Cl > (methylammonium hydrochloride). (20) With carboxylic acids, their anhydrides, halides, esters and other derivatives gives amides. With aldehydes and ketones - Schiff bases, which can be reduced to the corresponding amines (reductive amination). At 1000 °C, ammonia reacts with coal, forming hydrocyanic acid HCN and partially decomposing into nitrogen and hydrogen. It can also react with methane, forming the same hydrocyanic acid: Liquid ammonia Liquid ammonia, although to a small extent, dissociates into ions, in which its similarity with water is manifested: Liquid ammonia, like water, is a strong ionizing solvent in which a number of active metals dissolve: alkali, alkaline earth, Mg, Al, as well as Eu and Yb. The solubility of alkali metals in liquid is several tens of percent. Some intermetallic compounds containing alkali metals also dissolve in liquid ammonia, for example Dilute solutions of metals in liquid ammonia are blue, concentrated solutions have a metallic sheen and look like bronze. During the evaporation of ammonia, alkali metals are released in pure form, and alkaline earth metals - in the form of complexes with ammonia 2+ with metallic conductivity. With weak heating, these complexes decompose into metal and. Dissolved in the metal gradually reacts to form an amide: complexation Due to their electron-donor properties, molecules can enter complex compounds as a ligand. Thus, the introduction of excess ammonia into solutions of salts of d-metals leads to the formation of their amino complexes: Complexation is usually accompanied by a change in the color of the solution, so in the first reaction the blue color () turns into dark blue, and in the second reaction the color changes from green (Ni () to blue-violet. The most stable complexes with form chromium and cobalt in the oxidation state ( +3). Ammine solutions are quite stable, with the exception of yellow-brown cobalt (II) ammonia, which is gradually oxidized by atmospheric oxygen to cherry-red cobalt (III) ammonia. In the presence of oxidizing agents, this reaction proceeds instantaneously. The formation and destruction of a complex ion is explained by a shift in the equilibrium of its dissociation. In accordance with the Le Chatelier principle, the equilibrium in a solution of the ammonia complex of silver shifts towards the formation of the complex (to the left) with an increase in the concentration and/or. With a decrease in the concentration of these particles in the solution, the equilibrium shifts to the right, and the complex ion is destroyed. This may be due to the binding of the central ion or ligands into any compounds that are stronger than the complex. For example, when nitric acid is added to a solution, the complex is destroyed due to the formation of ions, in which ammonia is more strongly bonded to the hydrogen ion: Getting ammonia The industrial method for producing ammonia is based on the direct interaction of hydrogen and nitrogen: This is the so-called Garber process. The reaction occurs with the release of heat and a decrease in volume. Therefore, based on the Le Chatelier principle, the reaction should be carried out at the lowest possible temperatures and at high pressures - then the equilibrium will be shifted to the right. However, the reaction rate at low temperatures is negligible, and at high temperatures, the rate of the reverse reaction increases. The use of a catalyst (porous iron with impurities and) made it possible to accelerate the achievement of an equilibrium state. Interestingly, in the search for a catalyst for this role, more than 20 thousand different substances were tried. Taking into account all the above factors, the process of obtaining ammonia is carried out under the following conditions: temperature 500 ° C, pressure 350 atmospheres, catalyst. Under industrial conditions, the principle of circulation is used - ammonia is removed by cooling, and unreacted nitrogen and hydrogen are returned to the synthesis column. This turns out to be more economical than achieving a higher reaction yield by increasing the pressure. To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used: Usually, it is obtained in a laboratory way by weak heating of a mixture of ammonium chloride with slaked lime. To dry ammonia, it is passed through a mixture of lime and caustic soda. Subject: Ammonia. Physical and chemical properties. Receipt and application. Lesson Objectives: know the structure of the ammonia molecule, physical and chemical properties, applications; be able to prove the chemical properties of ammonia: write down the equations for the reactions of ammonia with oxygen, water, acids and consider them from the point of view of the theory of electrolytic dissociation and redox processes. During the classes 1. Organizational moment of the lesson. 2. Learning new material. Ammonia - NH 3 Ammonia (in European languages ​​its name sounds like "ammoniac") owes its name to the oasis of Ammon in North Africa, located at the crossroads of caravan routes. In hot climates, urea (NH 2 ) 2 CO contained in animal waste decomposes particularly quickly. One of the degradation products is ammonia. According to other sources, ammonia got its name from the ancient Egyptian word amonian. So called people worshiping the god Amun. During their ritual ceremonies they sniffed ammonia NH 4 Cl, which evaporates ammonia when heated. 1. The structure of the molecule The ammonia molecule has the shape of a trigonal pyramid with a nitrogen atom at the top.. Three unpaired p-electrons of the nitrogen atom participate in the formation of polar covalent bonds with 1s-electrons of three hydrogen atoms (N-H bonds), the fourth pair of external electrons is unshared, it can form a donor-acceptor bond with a hydrogen ion, forming an ammonium ion NH 4 + . 2. Physical properties of ammonia Under normal conditions, it is a colorless gas with a pungent characteristic odor (the smell of ammonia), almost twice as light as air, poisonous. According to the physiological effect on the body, it belongs to the group of substances with an asphyxiant and neurotropic effect, which, when inhaled, can cause toxic pulmonary edema and severe damage to the nervous system. Ammonia has both local and resorptive effects. Ammonia vapor strongly irritates the mucous membranes of the eyes and respiratory organs, as well as the skin. This is what we perceive as a strong smell. Ammonia vapors cause profuse lacrimation, pain in the eyes, chemical burns of the conjunctiva and cornea, loss of vision, coughing fits, redness and itching of the skin. Solubility NH 3 in water is extremely high - about 1200 volumes (at 0 °C) or 700 volumes (at 20 °C) in a volume of water. 3. Getting ammonia In the laboratory In industry To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used: NH 4 Cl + NaOH = NH 3 + NaCl + H 2 O (NH 4 ) 2 SO 4 + Ca(OH) 2 = 2NH 3 + CaSO 4 + 2H 2 O Attention! Ammonium hydroxide unstable base, decomposes: NH 4 OH ↔ NH 3 + H 2 O When receiving ammonia, keep the test tube - the receiver upside down, since ammonia is lighter than air: The industrial method for producing ammonia is based on the direct interaction of hydrogen and nitrogen: N 2 (g) + 3H 2 (g) ↔ 2NH 3 (g) + 45.9 k J Conditions: catalyst - porous iron temperature - 450 - 500 ˚С pressure - 25 - 30 MPa This is the so-called Haber process (German physicist, developed the physico-chemical foundations of the method). 4. Chemical properties of ammonia For ammonia, reactions are characteristic: 1. with a change in the oxidation state of the nitrogen atom (oxidation reactions) 2. without changing the oxidation state of the nitrogen atom (addition) Reactions with a change in the oxidation state of the nitrogen atom (oxidation reactions) N-3 → N 0 → N +2 NH3 - a strong reducing agent. with oxygen 1. burning ammonia(when heated) 4NH 3 + 3O 2 → 2N 2 + 6H 2 0 2. Catalytic oxidation of ammonia (catalyst Pt - Rh, temperature) 4NH 3 + 5O 2 → 4NO + 6H 2 O with metal oxides 2 NH 3 + 3CuO \u003d 3Cu + N 2 + 3 H 2 O with strong oxidants 2NH 3 + 3Cl 2 = N 2 + 6HCl (when heated) ammonia is a fragile compound, decomposes when heated 2NH 3 ↔ N 2 + 3H 2 Reactions without changing the oxidation state of the nitrogen atom (addition - Formation of the ammonium ion NH 4+ by donor-acceptor mechanism) 5. Application of ammonia In terms of production volumes, ammonia occupies one of the first places; annually around the world receive about 100 million tons of this compound. Ammonia is available in liquid form or as an aqueous solution - ammonia water, which usually contains 25% NH 3 . Huge amounts of ammonia are further used to produce nitric acid, which is used to make fertilizers and a variety of other products. Ammonia water is also used directly as a fertilizer, and sometimes the fields are watered from tanks directly with liquid ammonia. Various ammonium salts, urea, urotropine are obtained from ammonia. It is also used as a cheap refrigerant in industrial refrigeration systems. Ammonia is also used to produce synthetic fibers such as nylon and kapron. In light industry, it is used in the cleaning and dyeing of cotton, wool and silk. In the petrochemical industry, ammonia is used to neutralize acidic waste, and in natural rubber production, ammonia helps preserve latex during its transportation from the plantation to the factory. Ammonia is also used in the production of soda using the Solvay method. In the steel industry, ammonia is used for nitriding - saturation of the surface layers of steel with nitrogen, which significantly increases its hardness. Doctors use aqueous solutions of ammonia (ammonia)in everyday practice: a cotton swab dipped in ammonia spirit brings a person out of a swoon. For humans, ammonia in such a dose is not dangerous. 3. Consolidation of the studied material No. 1. Carry out transformations according to the scheme: a) Nitrogen → Ammonia → Nitric oxide (II) b) Ammonium nitrate → Ammonia → Nitrogen c) Ammonia → Ammonium chloride → Ammonia → Ammonium sulfate For OVR, draw up an e-balance, for RIO, complete, ionic equations. No. 2. Write four equations for the chemical reactions that produce ammonia. 4. Homework P. 24, ex. 2.3; test Ammonia- NH3, hydrogen nitride, under normal conditions - a colorless gas with a pungent characteristic odor (smell of ammonia) This is the so-called Haber process (German physicist, developed the physico-chemical foundations of the method). The reaction occurs with the release of heat and a decrease in volume. Therefore, based on the Le Chatelier principle, the reaction should be carried out at the lowest possible temperatures and at high pressures - then the equilibrium will be shifted to the right. However, the reaction rate at low temperatures is negligible, and at high temperatures, the rate of the reverse reaction increases. Carrying out the reaction at very high pressures requires the creation of special equipment that can withstand high pressure, and hence a large investment. In addition, the equilibrium of the reaction, even at 700 °C, is established too slowly for its practical use. The use of a catalyst (porous iron with Al2O3 and K2O impurities) made it possible to accelerate the achievement of an equilibrium state. Interestingly, in the search for a catalyst for this role, more than 20 thousand different substances were tried. Taking into account all the above factors, the process of obtaining ammonia is carried out under the following conditions: temperature 500 ° C, pressure 350 atmospheres, catalyst. The yield of ammonia under such conditions is about 30%. Under industrial conditions, the principle of circulation is used - ammonia is removed by cooling, and unreacted nitrogen and hydrogen are returned to the synthesis column. This turns out to be more economical than achieving a higher reaction yield by increasing the pressure. To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used. Ammonia is usually obtained in the laboratory by weak heating of a mixture of ammonium chloride and slaked lime. To dry ammonia, it is passed through a mixture of lime and caustic soda. Very dry ammonia can be obtained by dissolving sodium metal in it and subsequently distilling it. This is best done in a system made of metal under vacuum. The system must withstand high pressure (at room temperature, the saturated vapor pressure of ammonia is about 10 atmospheres). In industry, ammonia is dried in absorption columns. Consumption rates per ton of ammonia For the production of one ton of ammonia in Russia, an average of 1200 nm³ of natural gas is consumed, in Europe - 900 nm³. Ammonia in medicine For insect bites, ammonia is applied externally in the form of lotions. A 10% aqueous ammonia solution is known as ammonia. Side effects are possible: with prolonged exposure (inhalation use), ammonia can cause reflex respiratory arrest. Topical application is contraindicated for dermatitis, eczema, other skin diseases, as well as for open traumatic injuries of the skin. In case of accidental damage to the mucous membrane of the eye, rinse with water (for 15 minutes every 10 minutes) or a 5% solution of boric acid. Oils and ointments are not used. With the defeat of the nose and pharynx - 0.5% solution of citric acid or natural juices. In case of ingestion, drink water, fruit juice, milk, preferably 0.5% citric acid solution or 1% acetic acid solution until the contents of the stomach are completely neutralized. Interaction with other drugs is unknown. Interesting Facts Vapors of ammonia can change the color of flowers. For example, blue and blue petals become green, bright red - black.
Cr. dot	132.25°C
Enthalpy of formation	-45.94 kJ/mol
Steam pressure	8.5 ± 0.1 atm
Chemical properties
pK a	9.21
Solubility in water	89.9 (at 0 °C)
Classification
Reg.  CAS number
PubChem
Reg. number EINECS	231-635-3
SMILES
InChI
RTECS	BO0875000
CHEBI
UN number	1005
ChemSpider
Data are given for standard conditions (25 °C, 100 kPa) unless otherwise noted.

The use of a catalyst (porous iron with impurities of Al 2 O 3 and K 2 O) made it possible to accelerate the achievement of an equilibrium state. Interestingly, in the search for a catalyst for this role, more than 20 thousand different substances were tried.

Considering all the above factors, the process of obtaining ammonia is carried out under the following conditions: temperature 500 ° C, pressure 350 atmospheres, catalyst. The yield of ammonia under such conditions is about 30%. Under industrial conditions, the principle of circulation is used - ammonia is removed by cooling, and unreacted nitrogen and hydrogen are returned to the synthesis column. This turns out to be more economical than achieving a higher reaction yield by increasing the pressure.

To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used:

Ammonia is usually obtained in the laboratory by weak heating of a mixture of ammonium chloride and slaked lime.

To dry ammonia, it is passed through a mixture of lime and caustic soda.

Very dry ammonia can be obtained by dissolving sodium metal in it and subsequently distilling it. This is best done in a system made of metal under vacuum. The system must withstand high pressure (at room temperature, the saturated vapor pressure of ammonia is about 10 atmospheres). In industry, ammonia is dried in absorption columns.

Consumption rates per ton of ammonia

The production of one ton of ammonia in Russia consumes an average of 1200 nm³ of natural gas, in Europe - 900 nm³.

The Belarusian "Grodno Azot" consumes 1200 Nm³ of natural gas per ton of ammonia, after the modernization the consumption is expected to decrease to 876 Nm³.

Ukrainian producers consume from 750 Nm³ to 1170 Nm³ of natural gas per tonne of ammonia.

UHDE technology claims consumption of 6.7 - 7.4 Gcal of energy resources per ton of ammonia.

Ammonia in medicine

For insect bites, ammonia is applied externally in the form of lotions. 10% aqueous ammonia solution is known as

Hydrogen, under normal conditions - a colorless gas with a pungent characteristic odor (the smell of ammonia)

• Halogens (chlorine, iodine) form dangerous explosives with ammonia - nitrogen halides (nitrogen chloride, nitrogen iodide).

• With haloalkanes, ammonia enters into a nucleophilic addition reaction, forming a substituted ammonium ion (a method for obtaining amines):

• With carboxylic acids, their anhydrides, acid halides, esters and other derivatives gives amides. With aldehydes and ketones - Schiff bases, which can be reduced to the corresponding amines (reductive amination).

• At 1000 °C, ammonia reacts with coal, forming hydrocyanic acid HCN and partially decomposing into nitrogen and hydrogen. It can also react with methane, forming the same hydrocyanic acid:

Name history

Ammonia (in European languages, its name sounds like "ammoniac") owes its name to the oasis of Ammon in North Africa, located at the crossroads of caravan routes. In hot climates, urea (NH 2) 2 CO contained in animal waste decomposes especially quickly. One of the degradation products is ammonia. According to other sources, ammonia got its name from the ancient Egyptian word amonian. So called people worshiping the god Amun. During their ritual rites, they sniffed ammonia NH 4 Cl, which, when heated, evaporates ammonia.

Liquid ammonia

Liquid ammonia, although to a small extent, dissociates into ions (autoprotolysis), in which its similarity with water is manifested:

The self-ionization constant of liquid ammonia at −50 °C is approximately 10 −33 (mol/l)².

The metal amides resulting from the reaction with ammonia contain the negative ion NH 2 − , which is also formed during the self-ionization of ammonia. Thus, metal amides are analogues of hydroxides. The reaction rate increases when going from Li to Cs. The reaction is greatly accelerated in the presence of even small impurities of H 2 O.

Metal-ammonia solutions have metallic electrical conductivity; in them, metal atoms decay into positive ions and solvated electrons surrounded by NH 3 molecules. Metal-ammonia solutions containing free electrons are the strongest reducing agents.

complexation

Due to their electron-donating properties, NH 3 molecules can enter complex compounds as a ligand. Thus, the introduction of excess ammonia into solutions of salts of d-metals leads to the formation of their amino complexes:

Complexation is usually accompanied by a change in the color of the solution. So, in the first reaction, the blue color (CuSO 4) turns into dark blue (color of the complex), and in the second reaction, the color changes from green (Ni (NO 3) 2) to blue-violet. The strongest complexes with NH 3 form chromium and cobalt in the +3 oxidation state.

Biological role

Ammonia is the end product of nitrogen metabolism in humans and animals. It is formed during the metabolism of proteins, amino acids, and other nitrogenous compounds. It is highly toxic to the body, so most of the ammonia during the ornithine cycle is converted by the liver into a more harmless and less toxic compound - urea (urea). Urea is then excreted by the kidneys, and some of the urea can be converted by the liver or kidneys back into ammonia.

Ammonia can also be used by the liver for the reverse process - the resynthesis of amino acids from ammonia and keto analogs of amino acids. This process is called "reductive amination". Thus, aspartic acid is obtained from oxaloacetic acid, glutamic acid is obtained from α-ketoglutaric acid, etc.

Physiological action

According to the physiological effect on the body, it belongs to the group of substances with an asphyxiant and neurotropic effect, which, when inhaled, can cause toxic pulmonary edema and severe damage to the nervous system. Ammonia has both local and resorptive effects.

Ammonia vapor strongly irritates the mucous membranes of the eyes and respiratory organs, as well as the skin. This is a person and perceives as a pungent smell. Ammonia vapors cause profuse lacrimation, pain in the eyes, chemical burns of the conjunctiva and cornea, loss of vision, coughing fits, redness and itching of the skin. When liquefied ammonia and its solutions come into contact with the skin, a burning sensation occurs, a chemical burn with blisters and ulcerations is possible. In addition, liquefied ammonia absorbs heat during evaporation, and frostbite of varying degrees occurs when it comes into contact with the skin. The smell of ammonia is felt at a concentration of 37 mg/m³.

Application

Ammonia is one of the most important products of the chemical industry, its annual world production reaches 150 million tons. It is mainly used for the production of nitrogen fertilizers (ammonium nitrate and sulfate, urea), explosives and polymers, nitric acid, soda (ammonia method) and other chemical products. Liquid ammonia is used as a solvent.

Consumption rates per ton of ammonia

The production of one ton of ammonia in Russia consumes an average of 1200 nm³ of natural gas, in Europe - 900 nm³.

Belarusian "Grodno Azot" consumes 1200 Nm³ of natural gas per tonne of ammonia, after the modernization the consumption is expected to decrease to 876 Nm³.

Ukrainian producers consume from 750 Nm³ to 1170 Nm³ of natural gas per tonne of ammonia.

UHDE technology claims consumption of 6.7 - 7.4 Gcal of energy resources per ton of ammonia.

Ammonia in medicine

For insect bites, ammonia is applied externally in the form of lotions. A 10% aqueous ammonia solution is known as ammonia.

Side effects are possible: with prolonged exposure (inhalation use), ammonia can cause reflex respiratory arrest.

Topical application is contraindicated for dermatitis, eczema, other skin diseases, as well as for open traumatic injuries of the skin.

In case of accidental damage to the mucous membrane of the eye, rinse with water (for 15 minutes every 10 minutes) or a 5% solution of boric acid. Oils and ointments are not used. With the defeat of the nose and pharynx - 0.5% solution of citric acid or natural juices. In case of ingestion, drink water, fruit juice, milk, preferably 0.5% citric acid solution or 1% acetic acid solution until the contents of the stomach are completely neutralized.

Interaction with other drugs is unknown.

Ammonia producers

Ammonia producers in Russia

Russia accounts for about 9% of the world's ammonia output. Russia is one of the world's largest exporters of ammonia. About 25% of the total ammonia production is exported, which is about 16% of world exports.

Ammonia producers in Ukraine

• Jupiter's clouds are made up of ammonia.

see also

Notes

Links

• //
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.

Literature

• Akhmetov N. S. General and inorganic chemistry. - M.: Higher school, 2001.