Sodium carbonate is produced as a white powder. In the common people, this substance is called soda ash, in international production the name Sodium carbonate is used.

Soda has been used since ancient times, the Egyptians were the first to find it. They used it to wash dishes and to make glassware. Often it was found in salt layers that were underground. Soda lakes are also considered its deposit. It is found in some minerals and algae. Soda can be found in nahcolites, thermonitrites, and natrons.

The formula of sodium carbonate is Na2CO3. This substance can also be called sodium salt carbonic acid. Soda got its name due to the fact that in the process of its production, sodium bicarbonate is subjected to high heat. Modern manufacturers make this substance in a variety of ways. different ways. The most popular are the Solvay method and the chemical processing of minerals.

Physical properties

The molar mass of sodium carbonate is 105.9 g/mol. This substance has a low density - 2.54 g / cm³. Soda ash quickly dissolves in an aqueous medium, begins to boil at a temperature of 1600°C. This material has a high hygroscopicity, it easily absorbs odors and moisture. If sodium carbonate Na2CO3 is stored in open form, then it starts to sag.

Sodium carbonate react

This substance is able to react with a large number of chemical compounds.

Ammonium bicarbonate and sodium chloride in their reaction form a precipitate in the form of baking soda.

NH4HCO3 + NaCl = NaHCO3 + NH4C

Sodium carbonate in reaction with hydrochloric acid

Na2CO3 + 2HCl = 2NaCl + H2O + CO2

A solution of sodium carbonate and hydrochloric acid, as a result of the interaction, form edible salt, water and carbon dioxide, which evaporates into the air.

Soda ash is made by combining sodium hydroxide with carbon dioxide. As a result of this reaction, soda ash and water are formed.

2NaOH + CO2 = Na2CO3 + H2O

Acetic acid react with sodium carbonate

2CH3COOH + Na2CO3 = H2O + CO2 + 2CH3COONa

To obtain calcium carbonate, it is necessary to produce a reaction in which sodium carbonate and calcium chloride will participate.

Na2(CO3)+CaCl2=2NaCl+CaCO3 (precipitate)

Soda ash can react with sulfuric acid.

Na2CO3+H2SO4=NA2SO4 + H2O +CO2

Exchange reaction of sodium sulfide and calcium carbonate.

Na2S + CaCO3 → Na2CO3 + CaS

Sodium carbonate reacts quickly with water. An aqueous solution of sodium carbonate decomposes as follows:

Na2 (CO3) + 2H2O \u003d 2 Na + CO3 + 2H + 2OH

The interaction of sodium carbonate with calcium nitrate

Na2CO3 + Ca(NO3)2 → 2NaNO3 + CaCO3↓

The presented reaction equations for sodium carbonate show that this substance can be obtained in different ways. It is able to qualitatively interact with acids and water.

The use of soda ash

The scope of this substance is quite wide. Sodium carbonate solution is used in the food industry. Baking soda is added to many food formulations to regulate acidity, increase dough airiness, and emulsify.

Technical sodium carbonate finds its application in the field of glass production. Also, this substance is introduced into the composition of paper, soap, various cleaning and detergents. In heavy industry, it is used in the process of making cast iron products.

Great demand for this material is seen in:

• . in production non-ferrous metals,
• . oil refining industry,
• . textile production.

In the chemical field, other sodium salts are obtained by reactions with sodium carbonate.

Due to soda ash, water pipes are cleaned, and water hardness is also reduced.

As a result of the processing of carbonic acid with potassium and sodium salts, potassium-sodium carbonate is obtained. This material does not have a characteristic color, it quickly dissolves in the aquatic environment. It is used in the cement production process. It promotes rapid hardening.

Technical soda has a different purpose, it is produced in two grades:

Aqueous sodium carbonate grade B is used to prepare various detergents. It is also used to purify petroleum products. IN chemical industry it helps to obtain sodium, phosphorus and chromium salts.

Both grades of sodium carbonate are used in different types of glass. They are added to the compositions:

• . glasses for optical instruments,
• . glass blocks,
• . ceramic tiles,
• . medical glass,
• . foam blocks.

Grade A is used in the process of manufacturing electrovacuum glass. For this purpose, sodium carbonate must be of the highest grade.

Manufacturers and cost

The United States of America, Canada, Mexico and South Africa are considered world leaders in the production of this material. Large natural deposits are concentrated on their territory. IN Russian Federation soda lakes are located on the territory of Transbaikalia and Siberia.

The main industrial companies that produce sodium carbonate in Russia are:

• . OOO Yugreaktiv,
• . TransitChem LLC,
• . OOO AngaraReaktiv,
• . HIMPEK group of companies,
• . OOO NefteGazKhimKomplekt.

The average price of sodium carbonate is 20-25 rubles per 1 kg. Packed soda ash in plastic bags and cardboard packaging.

"Paleontology and Calcium Carbonate"

Calcium carbonate

Calcium carbonate(calcium carbonate) - an inorganic chemical compound, a salt of carbonic acid and calcium.

Chemical formula- CaCO 3 .

calcium carbonate in nature

Calcium carbonate is the basis of most natural calcium minerals (chalk, marble, limestone, shell rock, calcite, Icelandic spar). IN pure form substance white color or colorless crystals. Calcium compounds - limestone, marble, gypsum (as well as lime - a product of burning limestone) have been used in construction for several millennia ago. Up to late XVIII For centuries, chemists considered lime to be a simple substance. In 1789, A. Lavoisier suggested that lime, magnesia, barite, alumina and silica are complex substances.

In the natural migration of calcium, a significant role is played by the “carbonate equilibrium”, associated with the reversible reaction of the interaction of calcium carbonate with water and carbon dioxide with the formation of soluble bicarbonate:

(the equilibrium shifts to the left or right depending on the concentration of carbon dioxide).

Calcium compounds are found in almost all animal and plant tissues. A significant amount of calcium is part of living organisms. The shells and shells of many invertebrates are composed of calcium carbonate CaCO 3, eggshell and others. In living tissues of humans and animals, 1.4-2% Ca (according to mass fraction); in a human body weighing 70 kg, the calcium content is about 1.7 kg (mainly in the composition of the intercellular substance of bone tissue).

Chemical properties of calcium carbonate

1. 
   Calcium carbonate, when heated, decomposes into the corresponding oxide and carbon dioxide.

1. 
   With water containing dissolved carbon dioxide, calcium carbonate reacts to form solutions of bicarbonates:

When heated, and even when trying to isolate the bicarbonate from the solution, removing water when room temperature, it decomposes according to the reverse reaction:

Ca 2 + + 2HCO 3 - \u003d CaCO 3 + CO 2 + H 2 O.

1. 
   Calcium carbonate reacts with acids to release carbon dioxide

1. 
   Calcium carbonate is insoluble in water and ethanol.

Calcite, calcareous spar is a mineral, one of the natural forms of calcium carbonate. Exceptionally widespread on the surface of the Earth, rock-forming mineral. Limestones, Cretaceous rocks, marls, carbonatites are composed of calcite. Calcite is the most common biomineral: it is part of the shells and endoskeleton of most invertebrates, as well as the integumentary structures of some unicellular organisms.

The name was proposed by Haidinger in 1845 and, like the name of the chemical element, comes from lat. calx (genus calcis) - lime.

In its pure form, calcite is white or colorless, transparent (Icelandic spar) or translucent, depending on the degree of perfection of the crystal structure. Impurities color it in different colors.

Limestone

Limestone is a sedimentary rock of organic origin, consisting mainly of calcite crystals. different size and formed with the participation of living organisms in marine basins.

Limestone, consisting mainly of the shells of marine animals and their fragments, is called shell rock. During metamorphism, limestone recrystallizes and forms marble.

The name of the limestone variety reflects the presence in it of the remains of rock-forming organisms, the area of ​​​​distribution, structure (for example, oolitic limestones), impurities (ferruginous), the nature of occurrence (platystone), geological age (Triassic).

Entire mountain ranges in the Alps are composed of limestones, limestone is also widespread in other places. Limestone has no sheen, it is usually light gray in color, but can be white or dark, almost black, bluish, yellowish or pink, depending on the composition of the impurities.

Marble

Marble (ancient Greek μάρμαρος - “white or shiny stone”) is a metamorphic rock consisting only of calcite, as well as organic compounds. Marbles appear by metamorphism at moderate temperatures and pressures from predominantly carbonate sedimentary rocks. Under these conditions, very small grains of calcium and magnesium carbonate of sedimentary rocks experience "blastez" - coarsening of crystals.

A huge number of marble deposits have been explored in the world. The most famous are Carrara in Italy, Parian and Pendelicon in Greece. In Russia, these are Kibik-Kordonskoye in the Krasnoyarsk Territory, Burovshchina in Transbaikalia, Ufaleyskoye in the Urals, Ruskealskoye and Belogorskoye in Karelia. The color of marble also depends on impurities.

Paleontology(from other Greek παλαιοντολογία) - the science of organisms that existed in past geological periods and preserved in the form of fossil remains, as well as traces of their life.

Paleontologists study not only the remains of animals and plants themselves, but also their fossilized traces, discarded shells and other evidence of their existence. Paleontology also uses the methods of paleoecology and paleoclimatology to reproduce the living environment of organisms, compare the modern habitat of organisms, suggest extinct habitats, etc.

Fossils or fossils have been used by humans since the Paleolithic. This is evidenced by the finds of necklaces made from fragments of extinct corals and sea ​​urchins used in burial rituals, and other archaeological finds. Various fossils are mentioned in legends, myths and fairy tales. So, belemnites call "devil's fingers" and in oriental tales they are considered as nails of genies, shells of foraminifers - nummulitids in legends about the battles of Alexander the Great are described as petrified coins.

The first scientific written documents about fossil organisms belong to the ancient Greek naturalists and philosophers. The successes of the natural sciences of the ancient Greeks were summarized in the writings of Aristotle, who lived in 384–322. before new era, - the great thinker of his time, who created the foundations of the classification of animals, the beginnings of comparative anatomy and embryology. Fossils he considered the remains of marine animals. Many centuries later, in the XV-XVI centuries. this view of fossils was supported by Leonardo da Vinci (1452-1519), although at that time there were other points of view, in particular, that fossils are objects created by God after the Flood.

In the XVII-XVIII centuries. intensive research begins various industries natural sciences. This led not only to the accumulation of vast factual material, but also to the emergence various ideas, hypotheses. Great importance in the development of paleontology were the works of the Swedish scientist Carl Linnaeus (1707–1778), the founder of classification and systematics. He divided all nature into three kingdoms: minerals, plants and animals. Brilliant scientists worked simultaneously with Linnaeus: Georges Buffon (1707–1788) in France and Mikhail Lomonosov (1711–1765) in Russia.

Buffon, considering the origin and development of life, the history of the animal and flora, emphasized a single plan of the structure of animals, spoke of the presence of intermediate forms between different groups of animals, and believed that the history of the development of the Earth has up to 75,000 years.

M. Lomonosov in his book "On the layers of the earth" explained the origin of sedimentary rocks their formation in marine basins. The fossil mollusks found in these rocks owe their origin to the seas that existed in past geological epochs. Lomonosov imagined the change of various periods of life on Earth as a successive alternation of the advance and retreat of the seas, explaining these phenomena by slow fluctuations of the land. The area of ​​distribution of living beings on Earth forms a special shell called the biosphere. The biosphere arose with the advent of living beings on Earth: it occupies the entire surface of the land, all the water bodies of the Earth (oceans, seas, lakes, rivers), penetrates into the atmosphere - most organisms rise into the air by more than 50 - 70 m, and spores of bacteria and fungi are brought to a height of up to 22 km. Life penetrates into the lithosphere, where it is concentrated mainly in the surface of the layers at a depth of up to 6-8 m, but some bacteria are found in layers at a depth of up to 2-3 km.

In the 1890s and early 19th century, surveyor and mining engineer William Smith made extensive use of fossils to establish links between rock formations in different places. He established the principle of succession of faunas, according to which each layer of sedimentary rock contains a certain type of fossil, which follow each other in a predictable order, even in layers separated by a huge distance.

A new stage in the development of paleontology begins with the appearance in 1859 of Charles Darwin's most complete theory of evolution at that time, which had a decisive influence on everything. further development natural sciences. Modern evolutionary paleontology was founded by Vladimir Kovalevsky. It was thanks to Kovalevsky's research and his findings that Darwinism acquired a paleontologically sound basis.

The conditions of existence on earth are very diverse and are determined by factors of both inorganic and organic order. Inorganic factors include: temperature, humidity, water salinity, pool depth, pressure. Organic factors include those relationships that organisms enter into with each other. These relationships are primarily expressed by food ties. Each species has its own range, occupying different parts of the earth's surface. All organisms on earth live in communities called biocenoses. The organisms that make up the biocenosis react differently to fluctuations in one or another environmental factor - salinity, temperature, pressure. Some can exist with wide fluctuations of one of the environmental factors, and then the prefix "evry" is added; others do not tolerate even a slight change in this factor, and then the prefix "wall" is added. If it is depth - eurybatic, stenobatny; salinity - euryhaline, stenohaline; temperature - eurythermal, stenothermal.

Ammonites - an extinct subclass of cephalopods that existed from the Devonian to the Cretaceous. Ammonites got their name in honor of the ancient Egyptian deity Amun with spiral horns. Most ammonites belong to the ecological group of nekton, that is, organisms floating freely in the water column. Some heteromorphic forms were representatives of the benthic (bottom) community. The best swimmers among ammonites were forms with a distinct keel. Many paleontologists believe that the complex lobed line is an adaptation to a wide distribution along the vertical in the water column (eurybacy), since the complex lobed line has a large area and better strengthens the shell. Ammonites are an extremely important group of marine fossils for stratigraphy. This group is important for determining the relative geologic age of sedimentary rocks and for separating Jurassic and Cretaceous sediments.

Nautiluses- a genus of cephalopods. It is the only extant genus of the subclass Nautiloids and the only extant cephalopods to have an external chambered shell. This subclass appeared in the Cambrian, and during the Paleozoic was very diverse. The spiral shell, 15–23 cm in diameter, is divided into 35–39 chambers connected in series by a long siphon. The mollusk lives in the front, largest chamber. The shell is used as a float and ballast. By pumping biogas into the shell chambers or pumping it out of them, the nautilus is able to float to the surface of the water or sink into its thickness.

Belemnites- representatives of the order of extinct invertebrates of the cephalopod mollusk class, belong to the shell cephalopod mollusks, since all parts of their shells were located inside the body. Belemnites lived from the Carboniferous to the Cretaceous, spread most widely from the Triassic, died out at the end of the Mesozoic. The belemnite rostrum is best preserved in the fossil state - a strong conical formation located at the posterior end of the body.

Brachiopods- type of marine invertebrates. Known since the Early Cambrian; reached their peak in the Devonian. At the turn of the early and late Paleozoic, part of the orders became extinct; in the Carboniferous and Permian periods, the orders of productids and spiriferids dominated. After the Permian-Triassic extinction, 4 orders have survived that have survived to this day. Brachiopods, due to the richness of the remains and their good preservation, are valuable index fossils for establishing the geological age of the layers containing them and the physical and geographical situation that once existed in a given area.

sea ​​urchins- class of echinoderms. Fossils have been known since the Ordovician. The body of sea urchins is usually almost spherical, ranging in size from 2-3 to 30 cm; covered with rows of calcareous plates. The plates, as a rule, are fixedly connected and form a dense shell (shell), which does not allow the hedgehog to change shape.

sea ​​lilies- one of the classes of echinoderms. Fossil crinoids are known from the Lower Ordovician. They flourished most in the Middle Paleozoic, when they numbered up to 11 subclasses and over 5,000 species, but by the end of the Permian period, most of them died out. Fossilized remains of sea lilies are among the most common fossils. Some limestone beds dating from the Paleozoic and Mesozoic are composed almost entirely of them. Fossil segments of the stalks of crinoids, resembling gear wheels, are called trochites.

Bivalves or lamellar molluscs - a class of marine and freshwater inactive mollusks, the body of which is flattened laterally and enclosed in a shell of two valves. Findings of the most ancient fossil bivalve mollusks date back to the beginning of the Cambrian period, their age is more than 500 million years. Total number currently living species is approximately 9,200 (according to other sources, more than 20 thousand). Bivalves are a class of invertebrates that are exclusively aquatic and are found in fresh and salt waters throughout the world. Most are benthic organisms and live by burrowing into bottom sediments or attaching themselves to underwater objects. Shell valves in bivalve mollusks are often symmetrical. The shell valves are connected by a ligament, a ligament consisting of a thickened stratum corneum of the shell. The shell wall is made up of three layers: external conchiolin (periostracum), internal calcareous (ostracum) and lower mother-of-pearl (hypostracum). The mineral component of the shell may be exclusively calcite, as in oysters, or calcite and aragonite. Sometimes aragonite also forms a nacreous layer. In other molluscs, the layers of aragonite and calcite alternate.

You roam the supermarket looking for a phosphate-free laundry detergent. Naturally, in order to find out which tool from the whole arsenal household chemicals suits you, pick up each package with the desired classification and see the composition of the product contained in it. Finally, they chose the right product, but in the process of studying all the washing powders of the store, they noticed a strange pattern: on each box or pack something was written like: "The product contains sodium carbonate." Every person has a little bit of curiosity, and you are no exception. I wanted to know what kind of substance it is, right? Today's article will add some information about this compound to your knowledge.

Definition

Sodium carbonate (formula Na 2 CO 3) is the sodium salt of carbonic acid. In different sources, it can be called differently: both sodium carbonate, and disodium trioxocarbonate, and soda ash. By the way, about the last name. The chemical compound now being discussed in its pure form is not the same baking soda, which is added to various products. Its name is sodium bicarbonate. Substances with the presence of sodium carbonate (and he, too) are called soda. The exception is caustic soda, the scientific name of which is the hydroxide of the metal of the same name. However, sodium bicarbonate reacts with this substance to form the compound now discussed. All other sodas are carbonate itself with water or hydrogen in one formula. Today, the properties, production and use of only pure sodium salt of carbonic acid are considered.

Sodium carbonate: physical properties

This substance in an anhydrous state has the form of a colorless crystalline powder (photo above). The structure of its crystal lattice depends on the ambient temperature: if the latter is not less than 350, but below 479 ° C, then it is monoclinic, if the temperature is higher - hexagonal.

Sodium carbonate: chemical properties

If it is lowered into a strong acid, then the carbonic acid, which is obtained during the reaction and is extremely unstable, will decompose into gaseous tetravalent carbon oxide and water. The second product of the reaction is the sodium salt of the corresponding acid (for example, when throwing crystals of the carbonate being discussed now into sulfuric acid, you get carbon dioxide, water, and sodium sulfate). In water, this compound will hydrolyze, due to which the neutral environment becomes alkaline.

Receipt

It can be obtained in several ways, they are all different, but this article will talk about only one. It is necessary to mix chalk and charcoal with sodium sulfate, and then bake this mixture at a temperature of about 1000 ° C. Coal will reduce the latter to sulfide, which, when reacted with calcium carbonate, forms a melt of calcium sulfide and the desired substance. It must be treated with water, then the unwanted sulfide is filtered out and the resulting solution is evaporated. The crude sodium carbonate formed is purified by recrystallization and then dehydrated by calcination. This method is called the Leblanc method.

Application

Industries that produce glass washing powders, soaps and enamels are indispensable without sodium carbonate, where it is used to obtain ultramarine. Also, with the help of it, water hardness is eliminated, metals are degreased and desulfatization is carried out, the object of which is blast-furnace pig iron. Sodium carbonate is a good oxidizer and acidity regulator, it contains washing dishes drugs, cigarettes and pesticides. He is also known as food supplement E500, which prevents the ingredients from clumping and caking. The substance discussed now is also necessary in order to prepare a photo developer.

Conclusion

That's what sodium carbonate is good for. In its pure form, it, perhaps, has never been met by many, however, its crystalline hydrates (these are all soda, except for caustic soda) are used by man almost everywhere. This is one of the substances whose compounds with water are used in industry much more often than they are in their pure form.

Many natural substances are actively used by man in industry, pharmaceuticals and cosmetology. At correct application they are capable of bringing us enormous benefits, but even when we systematically encounter such elements in medicines, foodstuffs and cosmetics, we are most often unaware of all the diversity of their qualities. Calcium carbonate can also be attributed to such substances, the use and properties of which we will now discuss in a little more detail.

Application of calcium carbonate

Calcium carbonate is mostly mined by humans from different kind minerals, after which it is actively used in industry. So after cleaning from impurities, this substance is actively used in the creation of paper, food, plastics, paints and rubber. He found a place in the development of household chemicals, as well as in construction.

Calcium carbonate is quite actively used in the manufacture of personal care products (for example, it is added to toothpaste), as well as in the medical industry. In food production, it usually plays the role of an anti-caking agent, as well as a separator in various dairy products.

Properties of calcium carbonate

Calcium carbonate is a white powder or crystals. It has no smell or taste. Such a substance is practically insoluble in water, but quite soluble in dilute hydrochloric or nitric acid, while the dissolution process is accompanied by active release of carbon dioxide. The substance "calcium carbonate" is the source of forty percent of calcium.

medicinal properties

Calcium carbonate is able to neutralize hydrochloric acid, contributing to a significant decrease in the acidity of the digestive juice. The drug has a fairly rapid effect, however, after the cessation of the buffer effect, there is a slight increase in the production of gastric juice.

Consumption of calcium carbonate helps to reduce the activity of osteoclasts and slow down bone resorption. Such a substance well optimizes the electrolyte balance.

Among other things, calcium carbonate directly supplies the human body with calcium, which is actively involved in the processes of blood clotting, as well as in the formation of bone tissue. Calcium is also needed for the excellent functioning of the heart and for the full transmission nerve impulses.

Application in medicine

The active substance Calcium carbonate can be used to treat patients with excessive acidity of gastric juice, as well as for diseases of the digestive system occurring against the background of such a disorder. Such ailments include exacerbation of the chronic form of gastritis, acute type of gastritis or duodenitis, symptomatic ulcerative lesions of various etiologies. Also on this list is an ulcer at the stage of exacerbation, reflux esophagitis, erosive lesions of the mucous membranes, heartburn (after excessive intake of nicotine, coffee, medications and dietary disorders).

Also, the use of calcium carbonate may be appropriate in the correction of osteoporosis, caries and rickets in children, in the treatment of tetany and osteomalacia. It is advised to take it with an increased human need for calcium, which is observed with breastfeeding, at the stage of active growth, during pregnancy and other similar conditions.

Sometimes calcium carbonate is used as adjuvant therapy for allergic reactions and hypocalcemia.

Additional Information

dosage of calcium carbonate. Application

Calcium carbonate is administered orally, without reference to the time of the meal, twice or thrice a day in the amount of 250-1000 mg.

It should be borne in mind that when consuming high doses of this drug for a long time, it is extremely important to systematically monitor the level of calcium in the patient's blood, as well as monitor the performance of the kidneys. If calcium carbonate tablets are produced in the form of tablets intended for the prevention and correction of caries, osteoporosis, and rickets, they should not be used as an antacid formulation.

Contraindications for calcium carbonate

The use of calcium carbonate is categorically not recommended if the patient has hypersensitivity to this element, as well as with hypercalcemia (overdose of vitamin D, hyperparathyroidism and bone metastases). Such a medication is contraindicated in nephrourolithiasis, multiple myeloma, chronic renal failure, phenylketonuria and sarcoidosis.

Side effects calcium carbonate

In some cases, the use of calcium carbonate can provoke allergic reactions, sometimes such treatment causes the appearance of dyspeptic phenomena, represented by flatulence, epigastric pain, nausea, diarrhea or constipation. When consuming more than two grams of calcium per day, the patient is likely to develop hypercalcemia. In addition, some patients with this treatment are faced with the problem of a secondary increase in gastric secretion.

Please note that exceeding the recommended dosage may lead to an overdose of calcium carbonate. This condition requires gastric lavage and taking activated carbon. In addition, symptomatic correction can be carried out, and, if necessary, measures are taken to maintain vital functions.

Thus, active substance calcium carbonate, the properties of which we have just considered, has a fairly wide range of applications and can be of great benefit to a person.

Ekaterina, www.site

P.S. The text uses some forms characteristic of oral speech.

carboxylic acids compounds that contain a carboxyl group are called:

Carboxylic acids are distinguished:

• monobasic carboxylic acids;
• dibasic (dicarboxylic) acids (2 groups UNSD).

Depending on the structure, carboxylic acids are distinguished:

• aliphatic;
• alicyclic;
• aromatic.

Examples of carboxylic acids.

Obtaining carboxylic acids.

1. Oxidation of primary alcohols with potassium permanganate and potassium dichromate:

2. Hydrolysis of halogenated hydrocarbons containing 3 halogen atoms at one carbon atom:

3. Obtaining carboxylic acids from cyanides:

When heated, the nitrile hydrolyzes to form ammonium acetate:

When acidified, acid precipitates:

4. Use of Grignard reagents:

5. Hydrolysis of esters:

6. Hydrolysis of acid anhydrides:

7. Specific methods for obtaining carboxylic acids:

Formic acid is obtained by heating carbon monoxide (II) with powdered sodium hydroxide under pressure:

Acetic acid is obtained by catalytic oxidation of butane with atmospheric oxygen:

Benzoic acid is obtained by oxidation of monosubstituted homologues with a solution of potassium permanganate:

Cannicaro's reaction. Benzaldehyde is treated with 40-60% sodium hydroxide solution at room temperature.

Chemical properties of carboxylic acids.

In an aqueous solution, carboxylic acids dissociate:

The equilibrium is shifted strongly to the left, because carboxylic acids are weak.

Substituents affect acidity through an inductive effect. Such substituents pull the electron density towards themselves and a negative inductive effect (-I) arises on them. Pulling the electron density leads to an increase in the acidity of the acid. Electron donor substituents create a positive inductive charge.

1. Formation of salts. Reacting with basic oxides, salts weak acids and active metals:

Carboxylic acids are weak, because mineral acids displace them from the corresponding salts:

2. Formation of functional derivatives of carboxylic acids:

3. Esters when an acid is heated with alcohol in the presence of sulfuric acid - an esterification reaction:

4. Formation of amides, nitriles:

3. The properties of acids are determined by the presence of a hydrocarbon radical. If the reaction proceeds in the presence of red phosphorus, it forms the following product:

4. Addition reaction.

8. Decarboxylation. The reaction is carried out by fusing an alkali with an alkali metal salt of a carboxylic acid:

9. Dibasic acid easily splits off CO 2 when heated:

Additional materials on the topic: Carboxylic acids.