Chemistry. Tutorial. Frenkel E.N.

M.: 20 1 7. - 3 51 p.

The tutorial is based on a methodology that the author has been successfully using for over 20 years. With its help, many schoolchildren were able to enter the chemistry departments and medical universities. This book is a tutorial, not a textbook. You will not come across here with a simple description of scientific facts and the properties of substances. The material is structured in such a way that, when faced with complex issues that cause difficulties, you will immediately find the author's explanation. At the end of each chapter there are quizzes and exercises to reinforce the material. For an inquisitive reader who just wants to expand their horizons, the Self-Teacher will provide an opportunity to master this subject from scratch. After reading it, you cannot help but fall in love with this most interesting science - chemistry!

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Table of contents
From author 7
PART 1. ELEMENTS OF GENERAL CHEMISTRY 9
Chapter 1. Basic concepts and laws of the subject "Chemistry" 9
1.1. The simplest concepts: substance, molecule, atom, chemical element 9
1.2. Simple and complex substances. Valence 13
1.3. Chemical reaction equations 17
Chapter 2. Main classes of inorganic compounds 23
2.1. Oxides 23
2.2. Acids 32
2.3. Grounds 38
2.4. Salts 44
Chapter 3. Elementary information about the structure of the atom 55
3.1. Structure of the Periodic Table of Mendeleev 55
3.2. The nucleus of an atom. Isotopes 57
3.3. Distribution of electrons in the field of the nucleus of an atom 60
3.4. The structure of the atom and the properties of the elements 65
Chapter 4. The concept of a chemical bond 73
4.1. Ionic bond 73
4.2. Covalent bond 75
4.3. Chemical bond and state of aggregation of matter. Crystal lattices 80
Chapter 5
5.1. The dependence of the rate of a chemical reaction on various factors 87
5.2. Reversibility of chemical processes. Le Chatelier's principle 95
Chapter 6 Solutions 101
6.1. The concept of solutions 101
6.2. Electrolytic dissociation 105
6.3. Ionic-molecular reaction equations 111
6.4. The concept of pH (hydrogen index) 113
6.5. Salt hydrolysis 116
Chapter 7
PART 2. ELEMENTS OF INORGANIC CHEMISTRY 130
Chapter 8 General properties metals 130
8.1. Internal structure and physical properties of metals 131
8.2. Alloys 133
8.3. Chemical properties of metals 135
8.4. Corrosion of metals 139
Chapter 9. Alkali and alkaline earth metals 142
9.1. Alkali metals 142
9.2. Alkaline earth metals 145
Chapter 10
Chapter 11
11.1. Properties of iron and its compounds 158
11.2. Obtaining iron (iron and steel) 160
Chapter 12 Hydrogen and Oxygen 163
12.1. Hydrogen 163
12.2. Oxygen 165
12.3. Water 166
Chapter 13 Carbon and Silicon 170
13.1. The structure of the atom and the properties of carbon 170
13.2. Properties of carbon compounds 173
13.3. The structure of the atom and the properties of silicon 176
13.4. Silicic acid and silicates 178
Chapter 14 Nitrogen and Phosphorus 182
14.1. The structure of the atom and the properties of nitrogen 182
14.2. Ammonia and ammonium salts 184
14.3. Nitric acid and its salts 187
14.4. Atomic structure and properties of phosphorus 189
14.5. Properties and significance of phosphorus compounds 191
Chapter 15 Sulfur 195
15.1. The structure of the atom and the properties of sulfur 195
15.2. Hydrogen sulfide 196
15.3. Sulfur dioxide and sulfurous acid 197
15.4. Sulfuric anhydride and sulphuric acid 198
Chapter 16 Halogens 202
16.1. Atomic structure and properties of halogens 202
16.2. Hydrochloric acid 205
SECTION 3. ELEMENTS OF ORGANIC CHEMISTRY 209
Chapter 17. Basic concepts of organic chemistry 210
17.1. The subject of organic chemistry. Theory of the structure of organic substances 210
17.2. Features of the structure of organic compounds 212
17.3. Classification of organic compounds 213
17.4. Formulas of organic compounds 214
17.5. Isomerism 215
17.6. Homologues 217
17.7. Names of hydrocarbons. International Nomenclature Rules 218
Chapter 18 Alkanes 225
18.1. The concept of alkanes 225
18.2. Homologous series, nomenclature, isomerism 225
18.3. The structure of molecules 226
18.4. Properties of alkanes 226
18.5. Preparation and use of alkanes 229
Chapter 19 Alkenes 232
19.1. Homologous series, nomenclature, isomerism 232
19.2. The structure of molecules 234
19.3. Properties of alkenes 234
19.4. Preparation and use of alkenes 238
19.5. The concept of alkadienes (dienes) 239
Chapter 20. Alkynes 244
20.1. Definition. Homologous series, nomenclature, isomerism 244
20.2. The structure of molecules 245
20.3. Properties of alkynes 246
20.4. Production and use of acetylene 248
Chapter 21. Cyclic hydrocarbons. Arenas 251
21.1. The concept of cyclic hydrocarbons. Cycloalkanes 251
21.2. The concept of aromatic hydrocarbons 252
21.3. The history of the discovery of benzene. The structure of the molecule 253
21.3. Homologous series, nomenclature, isomerism 255
21.4. Properties of benzene 256
21.5. Properties of benzene homologues 259
21.6. Preparation of benzene and its homologues 261
Chapter 22
22.1. Definition 263
22.2. Homologous series, nomenclature, isomerism 264
22.3. The structure of molecules 265
22.4. Properties of monohydric alcohols 266
22.5. Preparation and use of alcohols (on the example of ethyl alcohol) 268
22.6. Polyhydric alcohols 269
22.7. The concept of phenols 271
Chapter 23
23.1. Definition. Homologous series, nomenclature, isomerism 276
23.2. The structure of molecules 277
23.3. Properties of aldehydes 278
23.4. Obtaining and application of aldehydes on the example of acetaldehyde 280
Chapter 24. Carboxylic acids 282
24.1. Definition 282
24.2. Homologous series, nomenclature, isomerism 283
24.3. The structure of molecules 284
24.4. Properties of acids 285
24.5. Production and use of acids 287
Chapter 25 Fats 291
Chapter 26 Carbohydrates 297
Chapter 27
27.1. Amines 304
27.2. Amino acids 306
27.3. Squirrels 308
Chapter 28 Understanding Polymers 313
PART 4. PROBLEM SOLVING 316
Chapter 29. Basic Calculation Concepts 317
Chapter 30
30.1. Tasks on the topic "Gas" 320
30.2. Tasks on the topic "Methods of expressing the concentration of solutions" 324
Chapter 31
31.1. Registration of calculations according to the equations of reactions 330
31.2. Tasks on the topic "Quantitative composition of mixtures" 333
31.3. Tasks for "surplus-lack" 337
31.4. Tasks to establish the formula of a substance 342
31.5. Tasks that take into account the "yield" of the obtained substance 349

O organic chemistry , a section of chemistry, a natural science discipline, the subject of which is the compounds of carbon with other elements, calledorganic compounds, as well as the laws of transformation of these substances. Carbon forms compounds with most elements and has the most pronounced ability, compared with other elements, to form molecules of a chain and cyclic structure. The skeleton of such molecules can consist of a practically unlimited number of carbon atoms directly connected to each other, or include, along with carbon, atoms of other elements. For carbon compounds, the phenomenon of isomerism is most characteristic, i.e., the existence of substances that are identical in composition and molar mass, but differ in the sequence of coupling of atoms or their arrangement in space and, as a result, in chemical and physical properties. As a result of these features, the number of organic substances is extremely large, by the 70s. 20th century more than 3 million are known, while compounds of all other elements are a little more than 100 thousand.
Organic compounds are capable of complex and diverse transformations, essentially different from the transformations of inorganic substances, and play a major role in the construction and life of plant and animal organisms. Organic compounds include carbohydrates and proteins with which metabolism is associated; hormones that regulate this exchange; nucleic acids that are material carriers of the organism's hereditary traits; vitamins, etc. O. x. represents t. as if a kind of "bridge" between the sciences that study inanimate matter and higher form the existence of matter - life. Many phenomena and laws of chemical science, such as isomerism, were first discovered in the study of organic compounds.

Toclassification of organic compounds . All organic compounds are divided into three main series, or classes: acyclic, isocyclic and heterocyclic. The first class (fatty, or aliphatic) compounds include hydrocarbons and their derivatives with open chains: the homologous series of methane hydrocarbons, also called the series of saturated hydrocarbons, or alkanes; homologous series of unsaturated hydrocarbons - ethylene (alkenes), acetylene (alkynes), dienes, etc. (see Acyclic compounds). The class of isocyclic (carbocyclic) compounds includes hydrocarbons and their derivatives, in the molecules of which there are cycles of carbon atoms: hydrocarbons and their derivatives of the cycloparaffin, or polymethylene series, cyclic unsaturated compounds (see Alicyclic compounds, Cycloalkanes), as well as aromatic hydrocarbons and their derivatives containing benzene rings (in particular, polynuclear aromatic compounds, for example, naphthalene, anthracene). The class of heterocyclic compounds includes organic substances whose molecules contain cycles containing, in addition to carbon, atoms O, N, S, P, As, or other elements.
A separate genetic series is formed from each hydrocarbon (see Homological series), the representatives of which are formally produced by replacing the hydrogen atom in the hydrocarbon with one or another functional group that determines the chemical properties of the compound. Thus, the genetic series of methane CH4 includes methyl chloride CH3Cl, methyl alcohol CH3OH, methylamine CH3NH2, nitromethane CH3NO2, and others. rows make up the homologous series of derivatives: halogen-containing compounds, alcohols, amines, nitro compounds, etc.

Istoric reference. Sources of O. x. date back to ancient times (already then they knew about alcoholic and acetic fermentation, dyeing with indigo and alizarin). However, even in the Middle Ages (the period of alchemy), only a few individual organic substances were known. All research of this period was reduced mainly to operations, with the help of which, as it was then thought, some simple substances can be converted into others. Starting from the 16th century. (period of iatrochemistry) research was mainly aimed at the isolation and use of various medicinal substances: a number of essential oils were isolated from plants, diethyl ether was prepared, wood (methyl) alcohol and acetic acid were obtained by dry distillation of wood, tartaric acid was obtained from tartar, distillation of lead sugar - acetic acid, distillation of amber - succinic. A big role in O.'s formation x. belongs to A. Lavoisier, who developed the basic quantitative methods for determining the composition of chemical compounds, subsequently improved by L. Tenard, J. Berzelius, J. Liebig, J. Dumas. The principles of these methods (combustion of a sample of a substance in an oxygen atmosphere, trapping and weighing the products of combustion - CO2 and H2O) form the basis of modern elemental analysis, including microanalysis. As a result of the analysis of a large number of different substances, the previously dominant idea of ​​the fundamental difference between substances of plant and animal origin gradually fell away.
For the first time the name "organic compounds" occurs at the end of the 18th century. The term "O. x." was introduced by Berzelius in 1827 (in the first guide to O. x. written by him). The phenomenon of isomerism was discovered by F. Wöhler and Liebig in 1822-23. The first synthesis of organic matter was carried out by Wöhler, who obtained oxalic acid from cyanogen in 1824 and urea in 1828 by heating ammonium cyanate. Starting from the middle of the 19th century. the number of organic substances obtained synthetically is rapidly increasing. Thus, in 1842 N. N. Zinin obtained aniline by the reduction of nitrobenzene, in 1845 A. Kolbe synthesized acetic acid, in 1854 P. Berthelot - substances like fats. In 1861, A. M. Butlerov obtained the first artificial sugary substance, which he called methylenenitane, from which acrosis was subsequently isolated. The synthetic direction in O. x. is gaining more and more importance. As a result of the success of the synthesis, the prevailing idealistic idea of ​​the need for "life force" for the creation of organic substances was rejected.
Theoretical representations in O. x. They began to develop in the second quarter of the 19th century, when the radical theory was created (by Liebig, Wöhler, E. Frankland, R. Bunsen, and others). Its main position about the transition of a group of atoms - radicals from one compound to another remains unchanged in a large number of cases at the present time. Many physical and chemical methods for studying substances of unknown structure are based on this concept. Subsequently (1834-39) Dumas showed the possibility of replacing positively charged atoms in the radical with electronegative ones without serious changes in the electrochemical nature of the radical, which was considered impossible before Dumas.
The theory of radicals was replaced by the types theory (1848-51, 1853), created by Dumas, C. Gerard and O. Laurent. The latter managed to classify organic substances according to the types of the simplest inorganic compounds. So, alcohols were considered compounds like water, amines - like ammonia, haloalkyls - like hydrogen chloride. Later, F. A. Kekule established the fourth type - the type of methane, from which he produced all hydrocarbons. The theory of types made it possible to create a clear classification of organic compounds, which underlies the modern classification of organic substances. However, this theory sought only to explain the reactivity of organic substances and denied the fundamental possibility of knowing their structure. In 1853 Frankland, while studying organometallic compounds, introduced the concept of valency. In 1857, Kekule expressed the idea of ​​the possibility of carbon atoms bonding to each other and proved that carbon is tetravalent. In 1858, A. Cooper, using the valency rule and Kekule's position on the adhesion of carbon atoms, for the first time departs from the theory of types and writes formulas of organic substances that are very close to modern ones. However, the ideas of type theory were still very strong, and the creation of the theory continued to lag behind the development of experiment.
In 1861 Butlerov created chemical structure theory of organic matter. He entered into O. x. a number of new concepts: about the chemical bond, the order of bonds of atoms in a molecule, about the mutual influence of atoms directly connected or not connected with each other, etc. Butlerov's theory of structure brilliantly explained the cases of isomerism that were still incomprehensible at that time. In 1864 Butlerov predicted the possibility of isomerism of hydrocarbons and soon (1867) confirmed this by the synthesis of isobutane. The harmonious doctrine created by Butlerov underlies modern ideas about the chemical structure of organic substances. One of the most important provisions of the theory of structure - on the mutual influence of atoms - was subsequently developed by V. V. Markovnikov. A detailed study of this influence contributed to the further development of the theory of structure and ideas about the distribution of electron density and the reactivity of organic compounds.
In 1869 I. Wislicenus showed that the phenomenon of isomerism is also observed when the sequence of linkage of atoms in a molecule is exactly the same. He proved the identity of the structure of ordinary lactic acid and meat-lactic acid and came to the conclusion that subtle differences in the properties of molecules with the same structure should be sought in the different arrangement of their atoms in space. In 1874, J. van't Hoff and the French chemist J. Le Bel created a theory of spaces. arrangement of atoms in a molecule - stereochemistry. This theory, according to van't Hoff, is based on the idea of ​​a tetrahedral model of a tetravalent carbon atom and that optical isomerism is a consequence of the spatial asymmetry of the molecule, in which the carbon atom is connected to four different substituents. van't Hoff also suggested the possibility of another type of spatial isomerism in the absence of an asymmetric carbon atom in the molecule. Wislicenus soon proved that fumaric acid, which was previously considered a polymer of maleic acid, is its geometric isomer (geometric or cis-trans isomerism). It is clear that the stereochemical doctrine could be created only on the basis of ideas about the structure (structure) of the molecule in Butler's understanding.
By the end of the 19th century a large amount of factual material has accumulated, including on aromatic compounds; in particular, the chemistry of benzene, discovered by M. Faraday in 1825, was widely studied. The "benzene theory" of the structure of aromatic compounds was created in 1865 by Kekule. It suggests that carbon atoms in organic compounds can form rings. According to this theory, benzene has a symmetrical structure due to the ring-like structure of six methine CH groups linked alternately by single and double bonds. However, based on the Kekule structure of benzene, the presence of two ortho-substituted homologues or benzene derivatives should have been assumed, which was not actually observed. The resistance of benzene to strong oxidizing agents and some other so-called. aromatic properties benzene and its derivatives also contradicted the proposed formula. Therefore, Kekule introduced (1872) the concept of oscillation (rapid movement) of double bonds and eliminated the formal differences between the two ortho positions. Despite the fact that the structure of benzene according to Kekule was in conflict with the data on its physical and chemical properties, for a long time it was accepted without any changes by the vast majority of chemists. Thus, a number of questions remained unresolved from the point of view of the "classical" theory of structure. These questions also include the uniqueness of the properties of many other compounds with conjugated bond systems. The structure of benzene and other aromatic systems could only be established with the advent of physical methods of investigation and with the development of quantum-chemical concepts of the structure of organic substances.
Electronic submissions [B. Kossel (1916) and G. Lewis (1916)] gave a physical content to the concept of a chemical bond (a pair of generalized electrons); however, in the form in which they were formulated, these ideas could not reflect subtle transitions from covalent to ionic bonds in O. x. remained largely formal. It was only with the help of quantum-chemical teaching that a fundamentally new content was introduced into the fundamentally correct representations of the electronic theory.
Lewis' ideas about a pair of electrons that form a bond and are always strictly localized on this bond turned out to be approximate and in most cases could not be accepted.

Modern ideas of the theory of structure and significance Oh. Accounting for the quantum properties of the electron, the concept of electron density and the interaction of electrons in conjugated systems opened up new possibilities for considering questions of the structure, mutual influence of atoms in a molecule, and the reactivity of organic compounds (see Electronic Theories in Organic Chemistry, Quantum Chemistry). In saturated hydrocarbons, single C-C bonds (s-bonds) are indeed realized by a pair of electrons; in symmetrical hydrocarbons, the electron density in the space between the connected atoms S-S more the sum of the corresponding electron densities of the same isolated atoms and is symmetrically distributed about the axis connecting the centers of the atoms. The increase in electron density is the result of the overlapping of electron clouds of atoms along a straight line connecting their centers. In asymmetric paraffins, the possibility of incomplete symmetry in the electron density distribution appears; however, this asymmetry is so slight that the dipole moments of all paraffinic hydrocarbons are hardly detectable. The same applies to symmetrically constructed unsaturated hydrocarbons(for example, ethylene, butadiene), in which the C atoms are connected to each other by a double bond (s- and p-bond). The introduction of an electron-donating methyl group into the molecules of these substances, due to the high polarizability of the p-bond, leads to a shift in the electron density to the extreme carbon atom, and propylene (I) already has a dipole moment of 0.35 D, and 1-methylbutadiene - 0.68 D. density in these cases, it is customary to depict one of the following schemes:(The signs d+ and d- show the emerging partial charges on C atoms) A number of empirical O. x rules fit well into ideas about the distribution of electron density. So, from the above formula for propylene, it follows that when hydrogen halides are added to it heterolytically, the proton should be fixed at the site of the highest electron density, i.e., at the most "hydrogenated" carbon atom. The introduction of atoms or groups into hydrocarbon molecules that differ greatly in electronegativity from carbon or hydrogen atoms has a much stronger effect. For example, the introduction of an electrophilic substituent into hydrocarbon molecules leads to a change in the mobility of hydrogen atoms in C-H bonds, O-N, etc.
Approximately from the 2nd half of the 20th century. Oh. has entered a new phase. Many of its directions have developed so intensively that they have grown into large specialized sections, called on a scientific or applied basis (stereochemistry, chemistry of polymers, natural substances, antibiotics, vitamins, hormones, organometallic compounds, organofluorine compounds, dyes, etc.). Successes in theory and the development of physical research methods (for example, X-ray diffraction of molecules, ultraviolet and infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance, chemically induced dynamic nuclear polarization, mass spectrometry), as well as methods for identifying and separating various substances using chromatography, made it possible to quickly analyze the most complex organic connections and quickly solve many important problems. The use of physical methods for studying the kinetics of reactions of organic substances makes it possible to study reactions with a half-life of 10-8-10-9 sec. Correlation equations based on the principle of free energy linearity make it possible to quantify the relationships between the structure and reactivity of organic compounds, even those that have a physiological effect. X. turned out to be closely connected with related natural sciences - biochemistry, medicine and biology, the application of ideas and methods of O. x. in these sciences largely led to the development of a new direction - molecular biology.

Methods Oh. along with physical methods, research played an important role in establishing the structure of nucleic acids, many proteins, and complex natural compounds; with their help, the mechanism and regulation of protein synthesis were discovered (see Genetic Code). The synthetic possibilities of chemical chemistry have increased tremendously, leading to the production of such complex natural substances as chlorophyll, vitamin B12 (R. Woodworth), polynucleotides with a definite alternation of links (A. Todd, H. G. Koran), and others. the success of these methods is the development of automatic synthesis of many polypeptides, including enzymes.

ORGANIC CHEMISTRY- a section of chemistry, a natural science discipline, the subject of study of which is organic compounds, i.e. compounds of carbon with other elements, as well as the laws of transformation of these substances; sometimes organic chemistry is defined as the chemistry of hydrocarbons and their derivatives.

Influence of O. x. on the development of biology and medicine is very large. All living things are built mainly from organic compounds (see), and the metabolism underlying life processes is a transformation of ch. arr. organic compounds. Oh. underlies biochemistry (see) - science, which is one of the natural scientific foundations of medicine. Most medicinal substances are organic compounds; therefore O. x. along with physiology and biochemistry is a basis of pharmacology (see). Methods O. x. played an important role in establishing the structure of nucleic acids, many proteins and other complex natural compounds; with their help, the mechanisms and regulation of protein synthesis were discovered. Thanks to the increased possibilities of organic synthesis, such complex natural substances as polynucleotides with a given alternation of nucleotide units, cyanocobalamin, etc. have been artificially obtained.

The success of the organic Chemistry, which is of fundamental importance, was the development of methods for the synthesis of many biologically active polypeptides, including enzymes and certain hormones or their pharmacologically active analogues, as well as many drugs.

Besides, great importance acquired O.'s methods x. in modern, technology for the production of rubbers, plastics, synthetic dyes, pesticides, herbicides, plant growth stimulants.

Oh. studies the fine structure of organic substances: the order of connection of atoms in their molecules, the mutual spatial arrangement of atoms in the molecules of organic compounds, the electronic structure of atoms and their bonds in organic compounds. Besides, a subject of O. x. is the study of organic reactions, including their kinetics (see Kinetics of biological processes), energy and electronic mechanisms, as well as the development of new methods for the synthesis of organic substances in laboratory and production conditions.

Sections O. x. are devoted to the study of individual groups of organic substances in accordance with their classification, for example, the chemistry of hydrocarbons, the chemistry of amino acids, etc., or general theoretical issues, for example, the stereoisomerism of organic compounds, the mechanisms of organic reactions, as well as practically important aspects of O. x., for example , dye chemistry, organic drug chemistry, etc.

Organic compounds and some of their properties have been known to people since ancient times; even then they knew about alcoholic and acetic fermentation, dyeing with indigo and alizarin, etc.

Since the 16th century - the period of iatrochemistry (see) - research has been focused mainly on the isolation and use of various organic medicinal substances: essential oils, diethyl ether was prepared, methyl (wood) alcohol and acetic acid were obtained by dry distillation of wood, amber to-ta was obtained by distillation of amber. However O.'s emergence x. as an independent scientific discipline belongs only to the 19th century. For the first time the concept "organic chemistry" was used by I. Berzelius, to-ry called so chemistry of the substances which are formed in an organism of animals and plants. Important stages of O.'s formation x. was the implementation of the first chem. syntheses of organic substances - oxalic acid and urea, which showed the possibility of obtaining organic compounds outside a living organism, without the participation of "life force" (see Vitalism). These syntheses, as well as the work of Yu. Liebig, who proved that carbon is contained in all (organic) substances formed in a living organism, contributed to the emergence of the definition of O. x. as the chemistry of carbon compounds proposed by L. Gmelin. From the first quarter of the 19th century Attempts began to generalize the factual material at the disposal of O. x., in the form of various theories. The first such theory can be considered the theory of radicals, formulated by J. Gay-Lussac, according to which the molecules of organic substances consist of groups of atoms - radicals, constant and unchanging and capable of passing from one compound to another. Such radicals, according to J. Gay-Lussac, can exist in a free state for a long time, and they are retained in the molecule due to their opposite charges. The concept of radicals as groups of atoms capable of transferring from one molecule to another has been preserved to this day. However, all other provisions of this theory turned out to be erroneous.

Following the theory of radicals, the theory of types of Gerard (F. Gerard) and Laurent (A. Laurent) appeared. According to this theory, all organic substances are compounds formed by replacing certain atoms in the molecule of certain inorganic substances (eg, water, ammonia, etc.) with organic residues. That. organic compounds related to the types of water (alcohols, ethers), types of ammonia (primary, secondary and tertiary amines), etc. can be obtained. The theory of types played a positive role in its time, since it made it possible to create the first classification organic substances, some elements of which were preserved in later classifications. However, with the accumulation of facts and acquaintance with more complex substances, the theory of types increasingly turned out to be untenable.

An important stage in O.'s development x. was the creation of a theory of the structure of organic compounds. One of the prerequisites for the creation of this theory was the establishment by F. A. Kekule in 1857 of the constant tetravalence of carbon and the discovery by A. Cooper in 1858 of the ability of carbon atoms to combine with each other, forming chains. The creator of the theory of the structure of organic compounds was A. M. Butlerov (1861). The main provisions of this theory are as follows. All atoms that form a molecule of organic matter are connected in a certain sequence; they can be linked single -С-С-, double >С=С< или тройной -C-C- bond. The properties of a substance depend on the structure of molecules, that is, on the order in which atoms are connected and the nature of the bonds between them; these provisions explained the previously incomprehensible phenomenon of isomerism (see). Chem. the properties of each atom and atomic group are not fixed, they depend on the other atoms and atomic groups present in the molecule. This position of the theory of the structure of organic compounds on the mutual influence of atoms was developed by the student of A. M. Butlerov - V. V. Markovnikov. The theory of A. M. Butlerov, deeply materialistic, makes it possible to choose the best synthesis scheme and, according to the formula of the structure, as according to the drawing, to synthesize various organic substances.

From the moment of creation of the theory of a structure of organic compounds intensive development of O. x begins. Many sections O. x. become the theoretical basis for a number of industries (fuel chemistry, dye chemistry, drug chemistry, etc.).

In O.'s development x. N. N. Zinin, S. V. Lebedev, A. E. Favorskii, N. D. Zelinsky, V. M. Rodionov, A. N. Nesmeyanov, A. P. Orekhov, and many others also played an outstanding role. Among foreign scientists in the field O. x. widely known are L. Pasteur, E. Fisher, Berthelot (R. E. M. Berthelot), A. Bayer, R. Wilstetter, R. B. Woodward, etc.

Under the influence of the rapid development of physics in the theory of O. x. the principles of quantum or wave mechanics began to be widely used (see Quantum theory). Concepts arose about the orbitals of an electron (spaces of an atom, in which the probability of an electron's stay is greatest). Electronic representations in O. x. made it possible to understand and classify various facts of the mutual influence of atoms, which, as it turned out, is based on the redistribution of electron density. great attention in O. x. is devoted to the study of the electronic mechanism of organic reactions. These reactions proceed with the formation of free radicals having an atom with an unpaired electron, magnetically uncompensated, and therefore active, or ions carrying a positive or negative charge (carbocations and carboanions).

Deep connection O. x. with physics and physical chemistry (see) manifests itself not only in the study of the electronic nature of the chemical. bonds, the mutual influence of atoms and electronic mechanisms of reactions, but also in the broad development of the problems of kinetics and energetics of chemical. reactions.

O.'s feature x. second half of the 20th century are its successes in deciphering the structure and in the synthesis of such complex natural substances as proteins (see), nucleic acids (see), etc. The key to success in this area was the establishment of the mutual spatial arrangement of atoms in molecules, i.e. stereochemistry ( see) and conformations of organic molecules (see. Conformation). In parallel, the problem of studying the causes of optical isomerism and the synthesis of optically active compounds was solved.

To the success of O. x. should include the discovery and study of new classes of organic compounds, among which the first place is occupied by non-benzene aromatic compounds (cyclopeitadienyl anion and metallocenes, tropylium cation, azu-lenes, etc.), certain groups of element-organic compounds with very valuable practical regarding properties.

In the second half of the 20th century the further rapprochement of O. x proceeds. with biochemistry and biology, as a result of which a new section of chemistry arose - bioorganic chemistry.

Successes of O. x. became possible due to the widespread use of a number of physical methods along with chemical ones, which primarily include diffraction methods (radiography and electron diffraction), optical spectroscopy (in the visible, ultraviolet and infrared regions of the spectrum), magnetic radiospectroscopy: electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), mass spectrometry, determination of electric dipole moments. Among these methods, the most effective in terms of information content is nuclear magnetic resonance (see), including its varieties - proton-magnetic resonance and the 13C-NMR method, which is increasingly used. These methods not only accelerated the deciphering of the structure of molecules of organic compounds many times over, but also made it possible to create conditions for obtaining their complete geometric and energy characteristics, as well as to reveal the electronic mechanisms of reactions. In organic chemistry, biochemical methods are also used, for example, strictly specific enzymatic methods, immunol, methods, etc.

With the development of natural science, such new disciplines as molecular pathology and molecular pharmacology have appeared. An increasing number of diseases can be explained by the appearance of altered molecules of organic substances in the tissues. Rapidly developing molecular pharmacology makes it possible to find and characterize a large number of receptors in cells that specifically bind the drug under study. The study of receptors on molecular level opens prospects for the search for new drugs. O.'s penetration x. in biology and medicine made it possible to reveal the essence of certain processes that were previously considered purely biological. Thus, it was found that the hereditary characteristics of organisms are "recorded" in DNA molecules in the form of a certain sequence of nucleotides. Oh. penetrated into the most difficult sphere - in the sphere of the study of human mental activity. It turned out that organic substances alone can cause hallucinations in a healthy person, similar to hallucinations in mentally ill people, and other substances can remove these hallucinations. From the brain of humans and animals, peptides have been isolated that have an effect similar to that of morphine and its analogues (see Endogenous opiates). It is possible that a disturbance in the biosynthesis or reception of these peptides underlies the pathogenesis of mental illness, and the organic synthesis of their analogs resistant to the action of blood peptidases will be of great importance for anesthesiology, psychiatry, etc.

Apparently, the most effective achievements should be expected in those areas O. x., to-rye border on biology and medicine. This is the opening of the chem. fundamentals of malignant growth in the fight against malignant tumors, deciphering chem. the foundations of memory, the mechanism of the dynamics of development and differentiation of tissues, the disclosure of chem. bases of immunity, etc. In areas O. x., borderline with physics and physical chemistry, researches on deeper penetration into the nature chemical will proceed. bonds between atoms in an organic molecule, the quantitative relationships between the structure and reactivity of such molecules will be more accurately established, the mechanisms of reactions, into which organic compounds enter, will be studied more deeply. IN THE USSR scientific work according to O. x. carried out by the Research Institute of the Academy of Sciences of the USSR: Institute of Organic Chemistry. N. D. Zelinsky (IOC), Institute of Organic and Physical Chemistry. A. E. Arbuzova (IOPC), Institute of Petrochemical Synthesis im. A. V. Topchieva (INHS), Institute of Organoelement Compounds (INEOS), Institute of Bioorganic Chemistry im. M. M. Shemyakina, H PI and the Siberian Branch of the USSR Academy of Sciences: Novosibirsk Institute of Organic Chemistry (NIOC), Irkutsk Institute of Organic Chemistry (INOC), Institute of Petroleum Chemistry, as well as Research Institute of Republican Academies - Institute of Organic Chemistry of Chemistry of the Armenian SSR, Kirghiz SSR, Ukrainian SSR, Inst. of Fine Organic Chemistry. A. L. Mgdzhayan (Armenian SSR), Institute of Physical and Organic Chemistry (BSSR), Institute of Physical and Organic Chemistry im. P. G. Melikishvili (Georgian SSR), Institute of Organic Synthesis (Latvian SSR), etc.

The National Committee of Soviet Chemists is a member of the International Union of Pure and Applied Chemistry - IUPAC (International Union of Pure and Applied Chemie), which organizes congresses, conferences and symposia once every two years, including those on organic chemistry.

In connection with the general trend of medicine to approach the molecular level, the physician must clearly understand the structure and spatial configuration of the molecules of substances involved in metabolism (nucleic acids, proteins, enzymes, coenzymes, carbohydrates, lipids, etc.) in normal and pathology, as well as the structure of drug molecules.

Oh. is the basis for studying in medical universities and secondary medical schools. educational institutions biochemistry, pharmacology, physiology and other disciplines. An independent course is dedicated to her or she is read as part of a course in general chemistry. Many of the data obtained in research on O. x. are used in physical and colloidal chemistry, biology, histology, pathophysiology, general hygiene, the course of occupational diseases, etc.

Bibliography: Ingold K. Theoretical foundations of organic chemistry, trans. from English, M., 1973; Kram D. and X em m o n d J. Organic chemistry, trans. from English, M., 1964; Mathieu J.-P. and P a-n and co R. Course theoretical foundations organic chemistry, trans. from French, Moscow, 1975; M about p r and R.'s son and B about y d R. Organic chemistry, the lane with English. from English, M., 1974; Nesmeyanov A. N. and Nesmeyanov N. A. Beginnings of organic chemistry, vol. 1-2, M., 1974; Palm V. A. Introduction to theoretical organic chemistry, M., 1974; Ride K. Course of physical organic chemistry, trans. from English, M., 1972; P e-in about A. Ya. and 3 e of l of e of N to about in and V. V. Small practical work on organic chemistry, M., 1980; Reutov O. A. Theoretical problems organic chemistry, M., 1964; Roberts J. and K and with er and about M. Fundamentals of organic chemistry, trans. from English, vol. 1-2, M., 1978; With tepanenko B. N. Course of organic chemistry, part 1-2, M., 1976; he, Course of Organic Chemistry, M., 1979.

Periodicals- Journal of General Chemistry, M.-L., since 1931; Journal of Organic Chemistry, M.-L., since 1965; Chemistry of heterocyclic compounds, Riga, since 1965; Chemistry of natural compounds, Tashkent, since 1965; Bulletin de la Societe chi-mique de France, P., from 1863; Journal of the Chemical Society, Perkin Transaction, I. Organic and Bio-organic Chemistry, II. Physical Organic Chemistry, L., since 1972; Journal of Heterocyclic Chemistry, L., since 1964; Journal of Organic Chemistry, Washington, since 1936; Journal of the Orgariometailic Chemistry, Lausanne, since 1964; Journal of the Society of Organic Synthetic Chemistry of Japan, Tokyo, since 1943; Justus Liebigs Annalen der Chemie, Weinheim, from 1832; Organic Magnetic Resonance, L., since 1969; Organic Mass Spectrometry, L., since 1968; Organic Preparations and Procedures, N. Y., since 1969; Synthesis, Stuttgart, since 1969; Synthetic Communication, N. Y., since 1971; Tetrahedron, N. Y.-L., since 1957; Tetrahedron Letters, L., since 1959.

B. H. Stepanenko.

Organic chemistry is a branch of chemistry that studies carbon compounds, their structure, properties, methods of synthesis. Organic compounds are called carbon compounds with other elements. Carbon forms the largest number of compounds with the so-called organogen elements: H, N, O, S, P. The ability of carbon to combine with most elements and form molecules of various composition and structure determines the diversity of organic compounds (by the end of the 20th century, their number exceeded 10 million, now more than 20 million [source not specified 229 days]). Organic compounds play a key role in the existence of living organisms.

The subject of organic chemistry includes the following objectives, experimental methods and theoretical concepts:

Isolation of individual substances from plant, animal or fossil raw materials

Synthesis and purification of compounds

Determination of the structure of substances

Study of the mechanisms of chemical reactions

Identification of dependencies between the structure of organic substances and their properties

Story

Methods for obtaining various organic substances have been known since antiquity. The Egyptians and Romans used indigo and alizarin dyes found in plant matter. Many peoples knew the secrets of the production of alcoholic beverages and vinegar from sugar and starch-containing raw materials. During the Middle Ages, nothing was added to this knowledge, some progress began only in the 16th-17th centuries: some substances were obtained, mainly by distillation of certain plant products. In 1769-1785, Scheele isolated several organic acids, such as malic, tartaric, citric, gallic, lactic, and oxalic acids. In 1773, Ruel isolated urea from human urine. Products isolated from animal or vegetable raw materials had much in common, but differed from inorganic compounds. This is how the term "Organic Chemistry" arose - a branch of chemistry that studies substances isolated from organisms (definition of Berzelius, 1807). At the same time, it was believed that these substances can only be obtained in living organisms due to the “life force.” As is commonly believed, organic chemistry as a science appeared in 1828 when Friedrich Wöhler first obtained an organic substance - urea - as a result of evaporating an aqueous solution of ammonium cyanate ( NH4OCN). An important step was the development of the theory of valence by Cooper and Kekule in 1857, as well as the theory of chemical structure by Butlerov in 1861. These theories were based on the tetravalence of carbon and its ability to form chains. In 1865, Kekule proposed the structural formula for benzene, which became one of the major discoveries in organic chemistry. In 1875, van't Hoff and Le Bel proposed a tetrahedral model of the carbon atom, according to which the valences of carbon are directed towards the vertices of the tetrahedron, if the carbon atom is placed in the center of this tetrahedron. In 1917, Lewis suggested considering chemical bond using electron pairs. In 1931, Hückel applied quantum theory to explain the properties of alternative aromatic carbons, thereby establishing a new direction in organic chemistry - quantum chemistry. In 1933, Ingold studied the kinetics of a substitution reaction at a saturated carbon atom, which led to a large-scale study of the kinetics of most types of organic reactions. It is customary to present the history of organic chemistry in connection with discoveries made in the field of the structure of organic compounds, but such a presentation is more connected with the history of chemistry generally. It is much more interesting to consider the history of organic chemistry from the standpoint of the material base, that is, the actual subject of study of organic chemistry. At the dawn of organic chemistry, the subject of study was mainly substances of biological origin. It is to this fact that organic chemistry owes its name. Scientific and technological progress did not stand still, and over time, the main material base of organic chemistry became coal tar, which is released during the production of coke by calcining coal. It was on the basis of the processing of coal tar that the main organic synthesis arose at the end of the 19th century. In the 50-60s of the last century, the main organic synthesis was transferred to a new base - oil. Thus, a new field of chemistry appeared - petrochemistry. The huge potential that was laid in the new raw materials caused a boom in organic chemistry and chemistry in general. The emergence and intensive development of such a field as polymer chemistry is due primarily to a new raw material base. Despite the fact that modern organic chemistry still uses raw materials of biological origin and coal tar as a material base, the volume of processing of these types of chemical raw materials is small compared to oil refining . The change in the material and raw material base of organic chemistry was caused primarily by the possibility of increasing production volumes.

Classification of organic compounds

Rules and features of classification:

The classification is based on the structure of organic compounds. The basis of the description of the structure is the structural formula. Atoms of elements are denoted by Latin symbols, as they are indicated in the periodic table of chemical elements (Mendeleev's table). Hydrogen and electron-deficient bonds are indicated by a dotted line, ionic bonds are indicated by the indication of the charges of the particles that make up the molecule. Since the vast majority of organic molecules include hydrogen, it is usually not indicated when depicting the structure. Thus, if an insufficient valence is shown in the structure of one of the atoms, then one or more hydrogen atoms are located near this atom. Atoms can form cyclic and aromatic systems.

Main classes of organic compounds

Hydrocarbons are chemical compounds consisting only of carbon and hydrogen atoms. Depending on the topology of the structure of the carbon skeleton, hydrocarbons are divided into acyclic and carbocyclic. Depending on the multiplicity of carbon-carbon bonds, hydrocarbons are divided into saturated (alkanes or saturated), not containing multiple bonds in their structure and unsaturated or unsaturated - they contain at least one double and / or triple bond (alkenes, alkynes, dienes) . In turn, cyclic hydrocarbons are divided into alicyclic (with an open chain) and cycloalkanes (limited with a closed chain), aromatic hydrocarbons (unsaturated, containing a cycle). Acyclic (open chain) Carbocyclic (closed chain)

limiting unlimiting limiting unlimiting

with single bondwith double bondwith triple bondwith two double bondswith single bondwith benzene ring

methane series (alkanes) ethylene series (alkenes) acetylene series (alkynes) a series of diene hydrocarbons a series of polymethylenes (naphthenes) a series of benzene (aromatic hydrocarbons, or arenes). Compounds with heteroatoms in functional groups - compounds in which the carbon radical R is bonded to a functional group . By the nature of the functional groups are divided into:

Alcohols, phenols. Alcohols (obsolete alcohols, English alcohols; from Latin spiritus - spirit) are organic compounds containing one or more hydroxyl groups (hydroxyl, −OH) directly connected to a saturated (being in a state of sp³ hybridization) carbon atom. Alcohols can be considered as derivatives of water (H-O-H), in which one hydrogen atom is replaced by an organic functional group: R-O-H. In the IUPAC nomenclature, for compounds in which the hydroxyl group is bonded to an unsaturated (sp2 hybridized) carbon atom, the names "enols" (hydroxyl bonded to a vinyl C=C bond) and "phenols" (hydroxyl bonded to a benzene or other aromatic ring) are recommended. ).

Ethers (ethers) are organic substances having the formula R-O-R1, where R and R1 are hydrocarbon radicals. It must be taken into account that such a group may be part of other functional groups of compounds that are not simple ethers (for example, Oxygen-containing organic compounds).

Esters (esters) are derivatives of oxo acids (both carboxylic and mineral) RkE (= O) l (OH) m, (l ≠ 0), which are formally products of substitution of hydrogen atoms of hydroxyls -OH of the acid function for a hydrocarbon residue (aliphatic, alkenyl , aromatic or heteroaromatic); are also considered as acyl derivatives of alcohols. In the IUPAC nomenclature, esters also include acyl derivatives of chalcogenide analogues of alcohols (thiols, selenols, and tellurols). They differ from ethers, in which two hydrocarbon radicals are connected by an oxygen atom (R1-O-R2).

Compounds containing a carbonyl group

Aldehydes (from Latin alcohol dehydrogenatum - alcohol devoid of hydrogen) - a class of organic compounds containing a carbonyl group (C \u003d O) with one alkyl or aryl substituent.

Ketones are organic substances in the molecules of which the carbonyl group is bonded to two hydrocarbon radicals. General formula of ketones: R1–CO–R2. The presence in ketones of precisely two carbon atoms directly bonded to the carbonyl group distinguishes them from carboxylic acids and their derivatives, as well as aldehydes.

Quinones are fully conjugated cyclohexadienones and their annelated analogues. There are two classes of quinones: para-quinones with a para-arrangement of carbonyl groups (1,4-quinones) and ortho-quinones with an ortho-arrangement of carbonyl groups (1,2-quinones). Due to the ability to reversibly reduce to dihydric phenols, some derivatives of para-quinones are involved in the processes of biological oxidation as coenzymes of a number of oxidoreductases.

Compounds containing a carboxyl group (Carboxylic acids, esters)

Organometallic compounds

Heterocyclic - contain heteroatoms in the composition of the ring. They differ in the number of atoms in the cycle, in the type of heteroatom, in the number of heteroatoms in the cycle.

Organic origin - as a rule, compounds of a very complex structure, often belong to several classes of organic substances at once, often polymers. Because of this, they are difficult to classify and are isolated in a separate class of substances.

Polymers are substances of very large molecular weight, which consist of periodically repeating fragments - monomer units.

The structure of organic molecules

Organic molecules are mainly formed by covalent non-polar C-C bonds, or covalent polar C-O type, C-N, C-Hal. According to the Lewis and Kossel octet theory, a molecule is stable if the outer orbitals of all atoms are completely filled. Elements such as C, N, O, Halogens need 8 electrons to fill the outer valence orbitals, hydrogen only needs 2 electrons. Polarity is explained by the shift of the electron density towards the more electronegative atom.

The classical theory of valence bonds is not able to explain all types of bonds that exist in organic compounds, so the modern theory uses the methods of molecular orbitals and quantum chemical methods.

The structure of organic matter

The properties of organic substances are determined not only by the structure of their molecules, but also by the number and nature of their interactions with neighboring molecules, as well as by their mutual spatial arrangement. Most clearly, these factors are manifested in the difference in the properties of substances in different states of aggregation. Thus, substances that easily interact in the form of a gas may not react at all in the solid state, or lead to other products.

In solid organic matter, in which these factors are most clearly manifested, distinguish between organic crystals and amorphous bodies. The science of "organic solid state chemistry" is engaged in their description, the foundation of which is associated with the name of the Soviet physicist-crystallographer A.I. Kitaigorodsky. Examples of useful organic solids- organic phosphors, various polymers, sensors, catalysts, electrical conductors, magnets, etc.

Features of organic reactions

Inorganic reactions usually involve ions, they proceed quickly and to the end at room temperature. Discontinuities often occur in organic reactions covalent bonds with the formation of new ones. Typically, these processes require special conditions: a certain temperature, reaction time, and often the presence of a catalyst. Usually, not one, but several reactions occur at once, so the yield of the target substance often does not exceed 50%. Therefore, when depicting organic reactions, not equations are used, but schemes without calculating stoichiometry.

Reactions can proceed in a very complex way and in several stages, not necessarily in the way the reaction is conventionally depicted in the diagram. Carbocations R+, carbanions R−, radicals R+, carbenes CX2, radical cations, radical anions, and other active or unstable species, usually living for a fraction of a second, can appear as intermediate compounds. Detailed description of all transformations that occur at the molecular level during the reaction is called the reaction mechanism. Reactions are classified depending on the methods of breaking and forming bonds, methods of excitation of the reaction, its molecularity.

Determination of the structure of organic compounds

Throughout the existence of organic chemistry as a science, an important task has been to determine the structure of organic compounds. This means to find out which atoms are part of the compound, in what order these atoms are interconnected and how they are located in space.

There are several methods for solving these problems.

elemental analysis. It consists in the fact that the substance decomposes into simpler molecules, by the number of which it is possible to determine the number of atoms that make up the compound. Using this method, it is impossible to establish the order of bonds between atoms. Often used only to confirm the proposed structure.

Infrared spectroscopy and Raman spectroscopy (IR spectroscopy and Raman spectroscopy). The substance interacts with electromagnetic radiation (light) of the infrared range (absorption is observed in IR spectroscopy, and radiation scattering is observed in Raman spectroscopy). This light, when absorbed, excites the vibrational and rotational levels of the molecules. Reference data are the number, frequency and intensity of vibrations of the molecule associated with a change in the dipole moment (IR spectroscopy) or polarizability (Raman spectroscopy). Methods allow you to establish the presence of certain functional groups in the molecule. They are often used to confirm the identity of the test substance with some already known substance by comparing the spectra.

Mass spectroscopy. Substance under certain conditions (electron impact, chemical ionization, etc.) is converted into ions without loss of atoms (molecular ions) and with loss (fragmentation). Allows you to determine the molecular weight and sometimes allows you to establish the presence of various functional groups.

Method of nuclear magnetic resonance (NMR). Based on the interaction of nuclei with their own magnetic moment(spin) and placed in an external constant magnetic field, with electromagnetic radiation of the radio frequency range. One of the main methods that can be used to determine the chemical structure. The method is also used to study the spatial structure of molecules, the dynamics of molecules. Depending on the nuclei interacting with radiation, there are, for example: Proton magnetic resonance (PMR) method. Allows you to determine the position of 1H hydrogen atoms in a molecule. 19F NMR method. Allows you to determine the presence and position of fluorine atoms in a molecule. 31P NMR method. Allows you to determine the presence, position and valence state of phosphorus atoms in a molecule. 13C NMR method. Allows you to determine the number and types of carbon atoms in a molecule. Used to study the shape of the carbon skeleton of a molecule.

Unlike the first three, the last method uses a minor isotope of the element, since the nucleus of the main carbon isotope, 12C, has zero spin and cannot be observed by nuclear magnetic resonance, just like the 16O nucleus, the only natural oxygen isotope. The method of ultraviolet spectroscopy (UV- spectroscopy) or Spectroscopy of electronic transitions. The method is based on the absorption of electromagnetic radiation in the ultraviolet and visible regions of the spectrum during the transition of electrons in a molecule from the upper filled levels to vacant levels (excitation of the molecule). Most often used to determine the presence and characteristics of conjugated π-systems. Methods of analytical chemistry. Allow to determine the presence of certain functional groups by specific chemical reactions, the fact of the flow of which can be fixed visually or using other methods.

The methods described above, as a rule, are completely sufficient to determine the structure of an unknown substance.

If you entered the university, but by this time you have not figured out this difficult science, we are ready to reveal a few secrets to you and help you learn organic chemistry from scratch (for "dummies"). You just have to read and listen.

Fundamentals of Organic Chemistry

Organic chemistry is singled out as a separate subspecies due to the fact that the object of its study is everything that contains carbon.

Organic chemistry is a branch of chemistry that deals with the study of carbon compounds, the structure of such compounds, their properties and methods of connection.

As it turned out, carbon most often forms compounds with the following elements - H, N, O, S, P. By the way, these elements are called organogens.

Organic compounds, the number of which today reaches 20 million, are very important for the full existence of all living organisms. However, no one doubted, otherwise a person would simply have thrown the study of this unknown into the back burner.

The goals, methods and theoretical concepts of organic chemistry are presented as follows:

• Separation of fossil, animal or vegetable raw materials into separate substances;
• Purification and synthesis of various compounds;
• Revealing the structure of substances;
• Determination of the mechanics of the course of chemical reactions;
• Finding the relationship between the structure and properties of organic substances.

A bit from the history of organic chemistry

You may not believe it, but even in ancient times, the inhabitants of Rome and Egypt understood something in chemistry.

As we know they used natural dyes. And often they had to use not a ready-made natural dye, but extract it by isolating it from a whole plant (for example, alizarin and indigo contained in plants).

We can also remember the culture of drinking alcohol. The secrets of the production of alcoholic beverages are known in every nation. Moreover, many ancient peoples knew the recipes for cooking " hot water» from starch- and sugar-containing products.

This went on for many, many years, and only in the 16th and 17th centuries did some changes, small discoveries, begin.

In the 18th century, a certain Scheele learned to isolate malic, tartaric, oxalic, lactic, gallic and citric acids.

Then it became clear to everyone that the products that could be isolated from plant or animal raw materials had many common features. At the same time, they differed greatly from inorganic compounds. Therefore, the servants of science urgently needed to separate them into a separate class, and the term “organic chemistry” appeared.

Despite the fact that organic chemistry itself as a science appeared only in 1828 (it was then that Mr. Wöhler managed to isolate urea by evaporating ammonium cyanate), in 1807 Berzelius introduced the first term in the nomenclature in organic chemistry for teapots:

Branch of chemistry that studies substances derived from organisms.

The next important step in the development of organic chemistry is the theory of valence, proposed in 1857 by Kekule and Cooper, and the theory of the chemical structure of Mr. Butlerov from 1861. Even then, scientists began to discover that carbon is tetravalent and is able to form chains.

In general, since then, science has regularly experienced upheavals and unrest due to new theories, discoveries of chains and compounds, which allowed organic chemistry to also actively develop.

Science itself appeared due to the fact that scientific and technological progress was not able to stand still. He kept on walking, demanding new solutions. And when coal tar was no longer enough in the industry, people simply had to create a new organic synthesis, which eventually developed into the discovery of an incredibly important substance, which is still more expensive than gold - oil. By the way, it was thanks to organic chemistry that her "daughter" was born - a subscience, which was called "petrochemistry".

But this is a completely different story that you can study for yourself. Next, we suggest you watch a popular science video about organic chemistry for dummies:

Well, if you have no time and urgently need help professionals, you always know where to find them.