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Making nitrous oxide at home
There are several ways to obtain laughing gas. The most accessible at home is G. Davy’s method - the thermal decomposition of ammonium nitrate (ammonium nitrate) according to the reaction:
NH 4 NO 3 = N 2 O + 2H 2 O.
In laboratory conditions, it is more convenient to heat sulfamic acid with nitric acid:
NH 2 SO 2 OH + HNO 3 (73%) = N 2 O + H 2 SO 4 + H 2 O.
However, sulfamic and nitric acids are more difficult to obtain, so we will focus on the decomposition of ammonium nitrate. By the way, the decomposition of ammonium nitrate is used to synthesize nitrous oxide on an industrial scale.
When ammonium nitrate is heated, several reactions take place. Here are excerpts from the book L.I. Bagal Chemistry and Technology of Initiating Explosives (1975)
Ammonium nitrate, when heated slightly above its melting point (dry ammonium nitrate melts at 169.6°C), decomposes according to the reaction
NH 4 NO 3 NH 3 + HNO 3 (1)
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The reaction of decomposition to nitrous oxide and water was studied by Berthelot, Thomsen and Velay. The first two researchers found that the reaction was exothermic
NH 4 NO 3 => N 2 O + 2H 2 O + 8.8 kcal (2)
The main reactions of ammonium nitrate decomposition at temperatures up to 270°C are (1) and (2). Molten ammonium nitrate, when heated above 250-260°C, can release nitrogen oxides, nitrogen and water:
NH 4 NO 3 => 0.5N 2 + NO + 2H 2 O
4NH 4 NO 3 => 3N 2 + N 2 O 4 + 8H 2 O
3NH 4 NO 3 => 2N 2 + N 2 O 3 + 6H 2 O
Saunders (1922), based on the results of gas analysis, came to the conclusion that the main decomposition reactions at temperatures up to 260°C are (1) and (2), as well as the reaction
5NH 3 + 3HNO 3 => 4N 2 + 9H 2 O
In his opinion, decomposition during an explosion proceeds according to the reaction
8NH 4 NO 3 => 16H 2 O + 2NO 2 + 4NO + 5N 2
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For the normal process of formation of nitrous oxide by decomposition of ammonium nitrate, its temperature regime and degree of purity are of exceptional importance.
As can be seen from the above data, ammonium nitrate, when heated to 240-250°C, decomposes to form nitrous oxide and water, however, even at this temperature the resulting “raw” gas contains nitric acid vapor, nitrogen oxides NO and NO 2, ammonia, chlorine (due to chloride impurities), nitrogen and “fog” of sublimated ammonium nitrate. It is clear that such a mixture cannot be inhaled (if the idea arises of repeating Davy’s experiments), since it deadly! Moreover, if the flask is closed with a rubber stopper, then even after short-term use it gradually collapses (with the formation of completely harmless products).
Therefore, the method of producing laughing gas by heating ammonium nitrate in a frying pan (which is often recommended by “gurus” to laugh at “laymen”) looks like black humor at best.
Let's move on to the installation. Ammonium nitrate is decomposed in a Wurtz flask under gentle heating. It is better to use a thermometer, but you can do without it if necessary. As experience has shown, it is better to use heating to approximately 220°C, in which case a slight “boiling” of the melt is observed. The resulting “raw gas” for purification is first passed through an ice-cooled trap to collect distilled water mixed with nitric acid. Next, the gas passes through a Drexel flask with a solution of iron sulfate; it also serves as a kind of indicator of the rate of gas release. Then the gas is washed in an improvised washing machine (with a porous spray) with a solution of 5-7% alkali (sodium or potassium hydroxide), where it is cleared of NO 2, nitric acid, and chlorine. And finally, in the third wash with a porous spray, into which a solution of iron (II) sulfate is poured, nitrous oxide is cleared of NO and traces of remaining impurities. After this, the gas contains nitrous oxide with some water and nitrogen, as well as traces of NO 2 and NO.
It should be remembered that the purification of nitrous oxide, if it is used to repeat Davy's experiments, should be given special attention, otherwise the gas will be toxic.
Ammonium nitrate fertilizer (ammonium nitrate) was used as a reaction load.
(A) Nitrites
Subject to compliance exceptions specified in the general provisions for this subgroup, this heading includes nitrites, metal salts of nitrous acid (HNO 2) (heading).
(B) Nitrates
Subject to compliance exceptions, specified in the general provisions for this subgroup, this heading includes nitrates, salts of metals and nitric acid (heading), except ammonium nitrate and sodium nitrate, both pure and crude ( commodity item or ). (See below for other exceptions.)
Basic nitrates are also included here.
(A) neutral bismuth nitrate(Bi(NO 3) 3 5H 2 O). It is obtained by the action of nitric acid on bismuth; large colorless diffuse crystals. Used to produce oxides or salts of bismuth and some varnishes;
(b) basic bismuth nitrate(BiNO 3 (OH) 2). Obtained from neutral bismuth nitrate; pearly white powder, insoluble in water. Used in medicine (for the treatment of gastrointestinal diseases); in the production of ceramics (rainbow paints), in cosmetics, in the production of fuses, etc.
In addition to the above exceptions, Also don't turn on following products.
Nitrites and nitrates differ not only in name, they also have different elements in their formula. However, there is something that “makes them similar.” The scope of application of these substances is quite wide. They are also present in the human body, and if too much of them accumulates, the person receives severe poisoning, which can even lead to death.
Simply put, nitrates are salts of nitric acid. In their formula they contain a single-digit anion. Previously, nitrate was called . Now this is the name for minerals, as well as fertilizers used in agriculture.
Nitrates are produced using nitric acid, which attacks metals, oxides, salts and hydroxides. All nitrates can be diluted in water. In the solid state, they are strong oxidizing agents, but their properties disappear if nitric acid is added to the solution.
Nitrates retain their properties at ordinary temperatures, but at low temperatures they melt until they completely decompose. The process of obtaining these substances is very complex, so it will probably only be of interest to chemists.
Nitrates are the basis for explosives - these are ammonites and other substances. They are mainly used as mineral fertilizers. Now there is no longer a secret that plants use nitrogen from salt to build the cells of their bodies. The plant creates chlorophyll, which is what it lives on. But in the human body, nitrates become nitrites, which can lead a person to the grave.
Nitrites are also salts of nitric acid, but with a different formula in their chemical composition. Sodium and calcium nitrites are known. Nitrites of lead, silver, alkali, alkaline earth, and 3D metals are also known.
These are crystalline substances that are also inherent in potassium or barium. Some substances are highly soluble in water, while others, such as silver, mercury or copper nitrites, are poorly soluble in it. It is noteworthy that nitrites are also practically insoluble in organic solvents. But if you increase the temperature, the solubility of nitrites improves.
Humanity uses nitrites in the production of nitrogen dyes, for the production of caprolactam, and also as oxidizing and reducing reagents in the rubber, textile and metalworking industries. For example, sodium nitrite is a good preservative and is used in the production of concrete mixtures as a hardening accelerator and anti-frost additive.
Nitrites are poisonous to human hemoglobin, so they must be removed from the body daily. They enter the human body either directly or with some other substances. If the human body functions normally, the required amount of the substance remains, and the unnecessary is removed. But if a person is sick, a problem with nitrite poisoning arises.
The invention relates to the production of nitric acid salts. The essence of the method is that nitrite-nitrate solutions obtained by absorption of nitrogen oxides with soda or caustic soda are evaporated to a total salt concentration of 750-900 g/l without isolating the solid phase and at a temperature of 70-90 o C are sent for inversion, inversion the gases are diluted with air and returned to the absorption stage, and the contact separation of ammonia to produce nitrous gases is turned on periodically as sodium nitrite is processed, and the product solutions of sodium nitrate are processed into a salt product in a known manner, including crystallization and drying of the product. The technical result is that the method makes it possible to obtain sodium nitrate without producing sodium nitrite, and also to use nitric acid as a donor of nitrogen oxides at the inversion stage instead of the catalytic oxidation of ammonia. 1 salary f-ly, 1 ill.
The invention relates to the chemical industry and can be used in enterprises producing nitric acid salts. There is a known method for producing sodium nitrate by neutralizing a solution of soda and (or) sodium hydroxide with nitric acid (V.A. Klevke, N.N. Polyakov, L.Z. Arsenyeva. Technology of nitrogen fertilizers. - M.: Goskhimizdat, 1956, p. 94; RF patent 2159738 dated December 3, 1999. Method for producing sodium nitrate). The disadvantage of the known methods is the low concentration of sodium nitrate in the product solution (320-360 g/l) and the associated high consumption of steam for its concentration before crystallization of the finished product. The closest in technical essence is the method of obtaining sodium nitrate from nitrite-nitrate solutions by inverting the latter with nitric acid (M.A. Miniovich, V.M. Miniovich. Salts of nitrous acid. - M.: Chemistry, 1997, pp. 100-101 ). The disadvantage of this method is the need for simultaneous production of sodium nitrite and the use of expensive platinum catalysts for the conversion of ammonia to nitrogen oxides. The objective of this proposed invention is to develop a method for producing sodium nitrate from nitrite-nitrate solutions without the production of sodium nitrite, the demand for which is highly seasonal, as well as the use of nitric acid to produce nitrogen oxides at the inversion stage instead of the catalytic oxidation of ammonia with atmospheric oxygen. This goal is achieved by the fact that after the stage of ammonia oxidation with atmospheric oxygen, cooling of nitrous gases, their absorption with a solution of soda or caustic soda, the nitrite-nitrate solution is evaporated without isolating the solid phase to a total salt content of 750-900 g/l and sent for inversion. When a solution is mixed with non-concentrated nitric acid, a well-known reaction occurs intensively: 3NaNO 2 + 2HNO 3 = 3NaNO 3 + 2NO + H 2 O. The ratio of the flows of nitric acid and a solution of nitrite-nitrate salts, in which the sum of salts is 750-900 g/l, is maintained in such a way that the acidity of the intermediate production solution is in the range of 30-80 g/l HNO 3 . The resulting nitrogen oxides are blown off with air in an inversion column. Since the inversion is carried out in the presence of an increased concentration of sodium nitrite, the inversion gases are diluted with additional air before entering the absorption stage. During absorption, they are absorbed by a circulating solution containing excess alkalinity in the form of soda or sodium hydroxide. In this case, sodium nitrite and nitrate are formed again. The drawing shows a diagram of the implementation of the method for producing sodium nitrate. The start-up of the technological scheme is carried out in the traditional way: the contact apparatus is ignited at the ammonia conversion stage, for which ammonia gas and air are used. Nitrous gases pass through a waste heat boiler, where they are cooled to 200-220 o C and enter an absorber irrigated with a circulating nitrite-nitrate solution containing an excess amount of soda or caustic soda. This solution (the sum of salts is 320-400 g/l) is periodically taken for evaporation, where by evaporation the sum of salts (NaNO 2 + NaNO 3 + Na 2 CO 3) increases to 750-900 g/l. The temperature of the evaporated solution is maintained within 70-90 o C to prevent precipitation of the solid phase. This solution is sent to a continuous inversion reactor column, into which non-concentrated nitric acid containing 56-58 wt.% HNO 3 is simultaneously dosed. The ratio of the flows of nitric acid and a solution of nitrite-nitrate salts is selected in such a way that an acidic environment is maintained in the column and the intermediate product solution has an acidity of 30-80 g/l HNO 3 . Air is continuously supplied to the reactor, which, in addition to improving the mixing of the reagents, ensures the removal of nitrous gases from the reaction zone. The intermediate acidic solution of sodium nitrate is sent to a neutralizer, where it is neutralized to a pH of 8-10 by mixing with a solution of soda or caustic soda. The inverted nitrous gases are diluted with additional air and sent to an absorption column. After the accumulation of a certain amount of nitrite-nitrate solutions, the contact department is stopped, and the production of sodium nitrate continues due to inversion nitrous gases. In this case, as can be seen from the above reaction, the donor of nitric oxide is nitric acid, and the process continues as long as the reducing agent sodium nitrite is present in the system. As sodium nitrite is used up and the concentration of nitrous gases decreases, it becomes necessary to connect contact oxidation of ammonia. The resulting product solution of sodium nitrate is processed into a salt product according to a known method by evaporation, crystallization and separation of sodium nitrate, followed by drying it. Recycled mother liquors, after the accumulation of impurities (Cl-ions) in them, are used in the process of conversion of potassium nitrate from potassium chloride.
Formula of invention
1. A method for producing sodium nitrate, including the oxidation of ammonia with atmospheric oxygen, cooling of nitrous gases, their absorption with a solution of soda or caustic soda, evaporation of the resulting nitrite-nitrate solutions, inversion of sodium nitrite with nitric acid at a temperature of 70-90 o C with the return of inversion gases to the stage absorption, neutralization of the intermediate solution of sodium nitrate, evaporation, crystallization and drying of the finished product, characterized in that nitrite-nitrate solutions evaporated to a total salt concentration of 750-900 g/l without isolating the solid phase are sent for inversion and the acidity of the intermediate solution is maintained at 30-80 g/l HNO 3, and the inversion gases are diluted with air before returning to the absorption stage. 2. The method according to claim 1, characterized in that the ammonia oxidation stage is switched on periodically as sodium nitrite is processed in inversion and the concentration of inversion nitrous gases decreases.
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The invention relates to the field of recycling components of liquid rocket fuels, in particular the processing of special nitro mixtures, which are an oxidizer of rocket fuel, into fertilizers and salts
The invention relates to a method for producing alkali metal nitrate and alkali metal phosphate in the same technological process from phosphate raw materials and nitrate raw materials, including the following steps: a) interaction of phosphate raw materials with nitrate raw materials to form an aqueous nitrophosphate reaction mixture, followed by optional separation of solid material, b) introducing an aqueous nitrophosphate reaction mixture into the first ion exchange stage, carried out in the presence of a cation exchange resin saturated with alkali metal ions, to exchange cations present in the reaction mixture for alkali metal ions present in this resin, obtaining a stream enriched with ions alkali metal, c) carrying out the first crystallization of the stream obtained in step (b), under conditions ensuring crystallization of the alkali metal nitrate, and separating the crystallized alkali metal nitrate from the mother liquor, d) introducing the mother liquor formed in step (c) to a second ion exchange step carried out in the presence of an alkali metal ion-rich cation exchange resin to exchange cations present in the mother liquor for alkali metal ions present in the resin to produce an alkali metal ion-rich phosphate containing stream, and e) performing second crystallization of the stream obtained in step (d), under conditions ensuring crystallization of the alkali metal phosphate, and separation of the crystallized alkali metal phosphate from the mother liquor
The invention relates to the production of nitric acid salts
Chemistry is a fascinating science. Those who are interested not only in theory, but also try their skills in practice, know exactly what we are talking about. Every schoolchild is familiar with most of the elements from the periodic table. But has everyone been able to try mixing reagents and conducting chemical tests first-hand? Even today, not all modern schools have the necessary equipment and reagents, so chemistry remains a science open to independent study. Many seek to understand it more deeply by conducting research at home.
Not a single homemaker can do without nitric acid - an extremely important thing in the household. It is difficult to obtain the substance: it can only be purchased in a specialized store, where purchases are made using documents confirming the peaceful use of the substance. Therefore, if you are a DIYer, you most likely will not be able to get this component. This is where the question arises of how to make nitric acid at home. The process does not seem to be complicated, however, the output should be a substance of a sufficient level of purity and the required concentration. There is no way to do this without the skills of an experimental chemist.
It is reasonable to use nitric acid for safe purposes. The substance is used in the following areas of human activity:
Pure nitric acid in its unchanged form appears as a liquid substance, which upon contact with air begins to release white vapors. It freezes already at -42 o C, and boils at +80 o C. How to remove a substance such as nitric acid with your own hands at home?
The fuming substance is obtained by exposing the concentrate to sodium (potassium) nitrate (sodium (potassium) nitrate). As a result of the reaction, the desired substance and sodium (potassium) hydrogen sulfate are obtained. The reaction scheme looks like this: NaNO 3 + H 2 SO 4 => HNO 3 + NaHSO 4. Remember that the concentration of the resulting substance depends on before entering into the reaction.
Obtaining nitric acid at home with a lower concentration of the substance occurs in the same way, you only need to replace sodium nitrate with ammonium nitrate. The chemical equation looks like this: N.H. 4 NO 3 + H 2 SO 4 =>(N.H.4) 2 SO 4 + HNO 3 . Please note that ammonium nitrate is more accessible than potassium or sodium nitrate, which is why most researchers carry out the reaction based on it.
The higher the concentration of H 2 SO 4, the more concentrated the nitric acid will be. To obtain a balanced substance, it is necessary to increase the volume of electrolyte required for the reaction. To achieve the desired result, in practice they use the evaporation method, which consists of gradually reducing the volume of the electrolyte by about 4 times the original.
Sifted sand is poured into the bottom of the dish and a reservoir with electrolyte is placed. In this process, the gas stove is boiled by turning up or reducing the heat. The process takes a long time, so patience is important in this matter. Experts recommend using boilers - glass or ceramic tubes designed for chemical experiments, including evaporation. They neutralize the formation of bubbles and reduce the boiling force, preventing splashing of the substance. Under such conditions, it is permissible to obtain nitric acid at home with a concentration of about 93%.
To carry out the reaction you will need:
Obtaining nitric acid at home, like carrying out any other chemical reaction, requires the following precautions:
Now you know how to get nitric acid in a simple reaction. Be careful when using such a substance and use it only for peaceful purposes.