Organic chemistry. Organic compounds

Organic chemistry -section of chemistry studies carbon compounds, their structure, properties , methods of synthesis, as well as the laws of their transformations. Organic is called carbon compounds with other elements (mainly with H, N, O, S, P, SI, GE, etc.).

The unique ability of carbon atoms to bind with each other, forming a chain of different lengths, cyclic structures of different sizes, frame joints, compounds with many elements, various composition and structure, causes a variety of organic compounds. To date, the number of well-known organic compounds by much exceeds 10 million and increases every year by 250-300 thousand. The world around us is built mainly from organic compounds, they include: food, clothing, fuel, dyes, medicines, detergents, Materials for various industries and folk economics. Organic compounds play a key role in the existence of living organisms.

At the junction of organic chemistry with inorganic chemistry, biochemistry and medicine, chemistry of metal and elementorganic compounds, bioorganic and medical chemistry, chemistry of high molecular weight connections have arisen.

The main method of organic chemistry is synthesis. Organic chemistry studies not only compounds obtained from plant and animal sources (natural substances), but mainly compounds created artificially with the help of laboratory and industrial synthesis.

The history of the development of organic chemistry

Methods for producing various organic substances were known since antiquity. Thus, the Egyptians and the Romans used plant dyes are horn-de-indigo and alizarine. Many nations owned secrets of alcohol production on-pit-coves and vinegar from sugar and starch-containing raw materials.

At the time of the Middle Ages, there were practically nothing to do with these knowledge, some progress began only in the 16th and 16th centuries (the period of yatrochimia), when new organic compounds were allocated by distillation of plant products. In 1769-1785 K.V. Shelele Several organic acids were isolated: apple, wine, lemon, gallopa, dairy and oxal. In 1773 P. Rueel allocated urea from human urine. The substances allocated from the animal and plant raw materials had a lot of common, but differed from inorganic compounds. Thus, the term "organic chemistry" appeared - section of chemistry studies substances isolated from organisms (definition Y.y.. Bercelius., 1807). At the same time, it was believed that these substances can only be obtained in living organisms due to the "life force".

It is believed that organic chemistry as science appeared in 1828, when F. Völer For the first time, he received an organic substance - urea - as a result of evaporation of an aqueous solution of an inorganic substance - ammonium cyanate (NH 4 OCN). Further experimental work demonstrated the indisputable arguments of the inconsistency of the theory of "vitality". For example, A. Kolbe Synthesized acetic acid, M. Bertlo got methane from H 2 S and CS 2, and A.M. Butlers Synthesized saccharis substances from formalin.

In the middle of the 19th century The rapid development of synthetic organic chi-mii continues, the first industrial production of organic substances are created ( A. Gofman, W. Perkin-senior - synthetic dyes, fuchsin, cyanine and azacrays). Improvement open N.N. Zinin (1842) The method of synthesis of aniline served as the basis for the creation of anilic paint industry. In the laboratory A. Bayer. Natural dyes were synthesized - indigo, alizarine, indigoid, xanen and anthrakinone.

An important stage in the development of theoretical organic chemistry was the development F. Kekule Valentine theory in 1857, as well as the classical chemical structure theory A.M.. Butlerov In 1861, according to which atoms in molecules are connected in accordance with their valence, the chemical and physical properties of compounds are determined by the nature and number of atoms included in them, as well as the type of connections and the mutual influence of directly unbound atoms. In 1865 F.. Kekule Suggested a structural form of benzene, which became one of the most important discoveries in organic chemistry. V.V. Markovnikov and A.M. Zaitsev Formulated a number of rules for the first time tied the direction of organic reactions with the structure of the substances entering into them. In 1875 Vant-Goff and Le Bel They proposed a tetrahedral model of carbon atom, according to which the valence of carbon is directed to the tops of the tetrahedron, in the center of which placed a carbon atom. Based on this model, in combination with experimental studies I. Vistienhus (! 873), which showed the identity of the structural formulas (+) - lactic acid (made of acidic milk) and (±) -malic acid, the stereochemistry occurred - the science of the three-dimensional orientation of atoms in molecules, which predicted in the case of the presence of 4 different substituents The carbon atom (chiral structures) is the possibility of the existence of spatial-mirror isomers (antipodes or enantiomers).

In 1917 Lewis Suggested to consider chemical bond with electronic pairs.

In 1931 Hyukkel Applicated a quantum theory to explain the properties of the nebenzoid aromatic systems than founded a new direction in organic chemistry - quantum chemistry. This served as an impetus for the further intensive development of quantumochemical methods, in particular the method of molecular orbitals. The stage of penetration of orbital representations into organic chemistry opened the theory of resonance L. Polinganga (1931-1933) and further work K. Fukui, R. Woodvord and R. Hofman On the role of boundary orbitals in determining the direction of chemical reactions.

Mid 20 V. It is characterized by a particularly rapid development of organic synthesis. This was determined by the discovery of fundamental processes, such as obtaining olefins using or emissions ( Vittig, 1954), Dien Synthesis ( O. Dils. and K. Alder, 1928), manoborization of unsaturated compounds ( Brown, 1959), nucleotide synthesis and gene synthesis ( A. Todd, H. Korrana). Successes in the chemistry of metal-organic compounds are largely required A.N. Nesmeyanova and G.A. Razuvaeva. In 1951, the synthesis of ferrocene was carried out, the establishment of a "sandwich" structure of which R. Woodvord and J. Wilkinson It laid the beginning of the chemistry of metallocene compounds and generally organic chemistry of transition metals.

In 20-30 g. A.E. Arbuzov Creates the foundations of chemistry of phosphorodorganic compounds, which subsequently led to the discovery of new types of physiologically active compounds, complexons, etc.

In 60-80 g. C. Pedersen, D. Kram and J.M. Linen We develop the chemistry of crown ether, crypthand and other related structures that can form durable molecuing complexes, and thus suitable to the most important problem of "molecular recognition."

Modern organic chemistry continues its rapid development. New reagents are introduced into the practice of organic synthesis, fundamentally new synthetic methods and techniques, new catalysts, previously unknown organic structures are synthesized. There is constantly searching for organic new biologically active compounds. Many of the problems of organic chemistry are waiting for their solution, for example, a detailed establishment of the relationship structure - properties (including biological activity), establishing the structure and stereo-plated synthesis of complex natural compounds, the development of new regional and stereo-selective synthetic methods, the search for new universal reagents and catalysts .

The interest of the global community to the development of organic chemistry brightly prize-mon-strengthening by the presentation of the Nobel Prize in Chemistry 2010 R. Heku, A. Suzuki and E. Nagisi For work on the use of palladium catalysts in organic synthesis for the formation of carbon ties - carbon.

Classification of organic compounds

The classification is based on the structure of organic compounds. The basis of the description of the structure is the structural formula.

Basic classes of organic compounds

Hydrocarbons -compounds consisting only of carbon and hydrogen. They in turn are divided into:

Saturated - contain only single (σ-bonds) and do not contain multiple links;

Unsaturated - in their composition at least one dual (π-bond) and / or triple relationship;

With an open chain (alicyclic);

With closed chain (cyclic) - contain cycle

These include alkanes, alkenes, alkins, dienes, cycloalkanes, arena

Compounds with heteroatoms in functional groups - Compounds in which the carbon radical R is associated with the functional group. Such compounds are classified by the nature of the functional group:

Alcohol, Phenol(contain hydroxyl group it)

Simple ethers(Contain R-O-R or R-O-R grouping

Carbonyl compounds (Burn the RR group "C \u003d O), these include aldehydes, ketones, quinones.

Compounds containing carboxyl group (Coo or co -R), these include carboxylic acids, esters

Element and metallorganic connections

Heterocyclic compounds -contain heteroatoms in the cycle. They differ in the nature of the cycle (saturated, aromatic), according to the number of atoms in the cycle (three-, four-, five-, six-membered cycles, etc.), by nature heteroatom, by the number of heteroatoms in the cycle. This determines the huge variety of well-known and annually synthesized connections of this class. Chemistry of heterocycles is one of the most exciting and important areas of organic chemistry. It suffices to say that more than 60% of drugs of synthetic and natural origin relate to different classes of heterocyclic compounds.

Natural connections -compounds, as a rule, a sufficiently complex structure, often belonging to several classes of organic compounds immediately. Among them can be allocated: amino acids, proteins, carbohydrates, alkaloids, terpenes, etc.

Polymers - substances with a very large molecular weight consisting of periodically repeated fragments - monomers.

The structure of organic compounds

Organic molecules are mainly formed by covalent non-polar bonds C-C, or covalent polar bonds of type C-O, C-N, C-HAL. Polarity is explained by the displacement of the electron density towards the more electronegative atom. To describe the structure of organic compounds of chemists, the language of structural formulas of molecules are used, in which links between individual atoms are designated using one (simple, or single bond), two (double) or three (triple) valence strokes. The concept of a valence stroke, which has not lost its value to this day, introduced into organic chemistry A. Cooper In 1858

Very essential for understanding the structure of organic compounds is the concept of hybridization of carbon atoms. The carbon atom basically has an electronic configuration of 1S 2 2S 2 2P 2, on the basis of which it is impossible to explain the inherent carbon in its compounds 4 and the existence of 4 identical bonds in alkanes directed to the tetrahedron vertices. As part of the method of valence relations, this contradiction is permitted by the introduction of the concept of hybridization. When exciting is carried out s.→p.electron transition and subsequent, so-called sp-hybridization, and the energy of hybridized orbitals is intermediate between energies s.- I. p.-Evubitals. In the formation of connections in alkanes three r-Electron interact with one s.-Electron ( sp. 3-hybridization) and 4 identical orbitals arise under tetrahedral angles (109 ° C 28 ") to each other. Carbon atoms in alkenes are in sp. 2-hybrid state: each carbon atom has three identical orbital lying in the same plane at an angle of 120 about each other ( sp. 2 - Therbital), and the fourth ( r-Orbital) perpendicular to this plane. Overlapping r-Evubitals two carbon atoms forms a double (π) connection. Carbon atoms carrying a triple connection are in sp.-Hybrid state.

Features of organic reactions

In inorganic reactions, ions are usually involved, such reactions pass quickly and to the end at room temperature. In organic reactions, covalent bonds are often occurring with the formation of new ones. As a rule, these processes require special conditions: a certain temperature, reaction time of certain solvents, and often the presence of a catalyst. It usually proceeds not alone, but at once a few reactions, therefore, with the iso-bearing of organic reactions, the equations are used, but the schemes without calculating the sta-chio metry. The yields of target substances in organic reactions often do not exceed 50%, and the separation of them from the reaction mixture and purification require specific methods and techniques. To purify solids, as a rule, recrystallization from specially selected solvents is used. Liquid substances are purified by distillation at atmospheric pressure or in vacuo (depending on the boiling point). To control the progress of the reactions, the separation of complex reaction mixtures resort to various types of chromatography [thin-layer chromatography (TLC), preparative highly efficient liquid chromatography (HPLC), etc.].

Reactions can occur very difficult and in several stages. As intermediates, R ·, R + carbcations, R -, carbrenium carbanks, CX 2, cation radicals, anion radicals, and other active and unstable particles, usually living shares of seconds, may occur as intermediate compounds. A detailed description of all transformations occurring at the molecular level during the reaction is called reaction mechanism. By the nature of the breaking and formation of bonds, radical (homolitic) and ionic (heterolithic) pro-cess are distinguished. By type of transformations, chain radical reactions, the reaction of the nucleophilic (aliphatic and aromatic) substitution, the reaction of elimi-ni-rod, electrical addition, electrical substitution, condensation, cyclization, rearrangement processes, and other reactions are also classified by ways of their initiation (excitation ), their kinetic order (mono-molecular, bimolecular, etc.).

Definition of the structure of organic compounds

In the very time of the existence of organic chemistry as science, the most important task was to determine the structure of organic compounds. This means learn what atoms are part of the structure, in what order and how these atoms are interconnected and as located in space.

There are several methods for solving these tasks.

• Elemental analysis It is that the substance is decomposed into simpler molecules, by the number of which you can determine the number of atoms included in the compound. This method does not make it possible to establish the order of connections between atoms. It is often used only to confirm the proposed structure.
• Infrared spectroscopy (IR spectroscopy) and spectroscopy of combinational scattering (CD spectroscopy). The method is based on the fact that the substance interacts with the electromagnetic radiation (light) of the infrared range (in IR spectroscopy, the absorption is observed, in the RC spectroscopy - radiation scattering). This light when absorbing excites the cooler and rotational levels of molecules. The reference data is the number, frequency and intensity of oscillations of the molecule associated with the change in the dipole moment (IR) or polarizability (CR). The method allows you to establish the presence of functional groups, and is also often used to confirm the identity of the substance with some already known substance by comparing their spectra.
• Mass spectrometry. Substance under certain conditions (electronic blow, chemical ionization, etc.) turns into ions without loss of atoms (mole-chular ions) and with loss (fragmentation, fragmentary ions). The method allows op-re-dividing the molecular weight of the substance, its isotopic composition, sometimes the presence of functional groups. The nature of fragmentation allows you to do some of the facts about the characteristics of the structure and recreate the structure of the interviewed connection.
• Method of nuclear magnetic resonance (NMR) Based on the interaction of nuclei with its own magnetic torque (spin) and placed in an external constant magnetic field (reorientation of the spin), with variable electromagnetic radiation of the radio frequency range. NMR represents one of the most important and informative methods for determining the chemical structure. The method is also used to study the spatial structure and the dynamics of molecules. Depending on the kernels that interact with radiation differ, for example, the proton resonance method of the PMR, NMR 1 H), which makes it possible to determine the position of hydrogen atoms in the molecule. The NMR 19 F method allows to determine the presence and position of fluorine atoms. The NMR 31 P method provides information on the presence, valence condition and position of phosphorus atoms in the molecule. The NMR 13 C method allows to determine the number and types of carbon atoms, it is used to study the carbon skeleton of the molecule. In contrast to the first three in the last method, the non-core isotope of the element is used, since the core of the main isotope 12 C has a zero spin and cannot be observed by the NMR method.
• Method of ultraviolet spectroscopy (UV spectroscopy)or electronic transition spectroscopy. The method is based on the absorption of electrical magnetic radiation of the ultraviolet and visible region of the spectrum when moving electrons in a molecule from the upper filled energy levels on vacant (molecule excitation). Most often used to determine the presence and characteristics of conjugate π-systems.
• Methods of analytical chemistryallowed to determine the presence of some functional groups on specific chemical (qualitative) reactions, the fact of the flow of which can be recorded visually (for example, the appearance or change in color) or using other methods. In addition to chemical methods of analysis in organic chemistry, instrumental analytical methods are increasingly used, such as chromatography (thin layer, gas, liquid bone). The honorable place among them occupies chromatomass-spectraomery, which allows not only to estimate the degree of purity of the compounds obtained, but also half-reading mass spectral information about the components of complex mixtures.
• Methods for studying stereochemistry of organic compounds. From the beginning of the 80 g. It became apparent the feasibility of developing a new direction in pharmacology and pharmacy associated with the creation of enantiomerically pure drugs with the optimal ratio of therapeutic efficacy and safety. Currently, about 15% of all synthesized pharmaceuticals are presented with pure enantiomers. The reflection of this trend was the emergence of the term in the recent years of the term chiral switchthat in Russian translation means "switching to chiral molecules". In this regard, the methods of establishing an absolute configuration of chiral organic molecules and determine their optical purity are acquired in organic chemistry. The main method of determining the absolute configuration should be considered x-ray structural analysis (RSA), and optical purity - chromatography on columns with a fixed chiral phase and NMR method using special additional chiral reagents.

Communication of organic chemistry with the chemical industry

The main method of organic chemistry - synthesis - closely connects organic chemicals with the chemical industry. Based on the methods and development of synthetic organic chemistry, a low-tonnage (thin) organic synthesis arose, which includes the production of drugs, vitamins, enzymes, pheromones, liquid crystals, organic semiconductors, solar panels, etc. The development of large-capacity (basic) organic synthesis is also based At the achievements of organic chemistry. The main organic synthesis includes the production of artificial fibers, plastics, oil refining, gas and coal raw materials.

Recommended literature

• G.V. Bulls History of organic chemistry, M.: Mir, 1976 (http: //gen.lib/rus.ec/get? MD5 \u003d 29A9A3F2BDC78B44AD0BAD2D9AB87B87)
• J. March, Organic Chemistry: Reactions, Mechanisms and Structure, in 4 volumes, M.: Mir, 1987
• F. Keri, R. Sandberg, In-depth Organic Chemistry Course, in 2 volumes, M.: Chemistry, 1981
• O.A. Reutov, A.L. Kurtz, K.P. Butin, Organic chemistry, in 4 parts, M.: "Binin, Laboratory of Knowledge", 1999-2004. (http://edu.prmetey.org./library/autor/7883.html)
• Chemical encyclopedia, ed. Knunyanta, M.: "Big Russian Encyclopedia", 1992.

Organic Chemistry - Science, which studies carbon compounds, calledorganic substances. In this regard, organic chemistry is also called chemistry of carbon compounds.

The most important reasons for the allocation of organic chemistry into separate science are as follows.

1. The average of organic compounds compared to inorganic.

The number of well-known organic compounds (about 6 million) significantly exceeds the number of compounds of all other elements of the periodic Mendeleev system. Currently, about 700 thousand inorganic compounds are known, approximately 150 thousand new organic compounds are received in one year now. This is explained not only by the fact that chemists are particularly intensively involved in the synthesis and the study of organic compounds, but also the special ability of the carbon element to give compounds containing a practically unlimited number of carbon atoms associated in the chains and cycles.

2. Organic substances have an exceptional importance as a result of their extremely diverse practical application, and because they play a crucial role in the processes of the livelihoods of organisms.

3. There are significant differences in the properties and reactivity of organic compounds from inorganic, as a result, there was a need for the development of many specific methods for the study of organic compounds.

The subject of organic chemistry is the study of methods for producing, composition, structure and applications of the most important classes of organic compounds.

2. A brief historical overview of the development of organic chemistry

Organic chemistry as science took shape at the beginning of the XIX century, but the acquaintance of a person with organic substances and their use for practical purposes began in ancient times. The first known acid was vinegar, or aqueous solution of acetic acid. The ancient peoples were known to ferment the grape juice, they knew the primitive method of distillation and used it to obtain a turpidar; Galla and Germans knew soap cooking methods; In Egypt, Gaul and Germany were able to cook beer.

In India, the art of dyeing with organic substances has been highly developed in India, chiefs and Egypt. In addition, the ancient peoples used such organic substances as oils, fats, sugar, starch, gum, resin, indigo, etc.

The period of development of chemical knowledge in the Middle Ages (approximately the XVI century) received the name of the alchemy period. However, the study of inorganic substances was significantly more successful than the study of the substances of organic. Information about the latter remained almost as limited as in the oldest century. Some step forward was made thanks to the improvement of distillation methods. In this way, in particular, several essential oils were isolated and a strong wine alcohol was obtained, which was considered one of the substances with which the philosopher's stone can be prepared.

End of the XVIII century. marked noticeable success in the study of organic substances, and the organic substances began to explore with a purely scientific point of view. During this period, a number of major organic acids were described from plants and described a number of essential organic acids (sorveless, lemon, apple, gallovaya) and it was found that oils and fats contain as a total component "Sweet start of oils" (glycerin), etc.

The studies of organic substances are gradually started to develop - the productivity of animal organisms. So, for example, urea and urinary acid were isolated from the urine of man, and from the urine of a cow and horses - hypric acid.

The accumulation of significant actual material was a strong impetus for a deeper study of the organic matter.

For the first time, the concepts of organic substances and organic chemistry introduced the Swedish scientist Berzelius (1827). In the textbook of chemistry, withstood a lot of publications, Britzelius expresses the conviction that "In the wilderness, elements will obey other laws than in lifeless" and that organic substances cannot form under the influence of ordinary physical and chemical forces, but require special "vitality " He determined organic chemistry as "chemistry of plant and animal substances, or substances that are influenced by vitality." The subsequent development of organic chemistry proved the fallacy of these views.

In 1828, Vyler showed that an inorganic substance - cyanomassed ammonium - when heated, turns into a product of the life of the animal organism - urea.

In 1845, Kolbe synthesized a typical organic matter - acetic acid, using charcoal, sulfur, chlorine, chlorine and water as the starting materials. For a relatively short period, a number of other organic acids were synthesized, which were released only from plants before.

In 1854, Berthlo managed to synthesize substances related to the class of fats.

In 1861, A. M, Butlers the action of lime water to paraformaldehyde for the first time carried out the synthesis of methylenitan - a substance relating to the Sugar class, which, as is known, play an important role in the processes of livelihoods of organisms.

All these scientific discoveries led to the collapse of the vitalism - idealistic teaching about "life force."

1. The reaction of hydrolysis or washed. As already mentioned above, the esterification reaction is reversible, therefore, in the presence of acids, the reverse reaction, called hydrolysis, as a result of which the source fatty acids and alcohol are formed: the hydrolysis reaction is catalyzed and alkalis; In this case, the hydrolysis is irreversible: since the resulting carboxylic acid with alkali forms salt: R - Cooh ...

Proteins are natural polypeptides with high molecular weight values \u200b\u200b(from 10,000 to tens of millions). They are part of all living organisms and perform a variety of biological functions. You can select four levels in the structure of the polypeptide chain. Primary protein structure is a specific amino acid sequence in the polypeptide chain. The peptide chain has a linear structure only in a small ...

Rubbers are the polymerization products of dienes and their derivatives. Natural rubber is obtained from latex - juice of some tropical plants. Its structure can be established by chemical properties: the rubber connects bromine, bromomarodine and hydrogen, and when heated without access, air breaks down to form isoprene (2-methylbutadiene). This means that the rubber is an unintended polymer - polyisoprene. With more detailed ...

The most important of monosaccharides is glucose C6H12O6, which is otherwise called grape sugar. This is a white crystalline substance, sweet taste, well soluble in water. Glucose is contained in plant and living organisms, especially the great content in grape juice (hence the name - grape sugar), in honey, as well as in ripe fruits and berries. The structure of glucose is derived ...

The physical properties of proteins are very diverse and determined by their structure. According to physical properties, proteins are divided into two classes: globular proteins dissolve in water or form colloidal solutions, fibrillated proteins in water are insoluble. Chemical properties. 1. The destruction of the secondary and tertiary protein structure with the preservation of the primary structure is called denaturation. It occurs when heated, changes in the acidity of the medium, the action of radiation ....

The industrial demand for rubber significantly exceeds the possibility of its natural sources, so chemists had to solve the problem of rubber synthesis, not inferior by the properties of natural product. The first industrial synthetic rubber was obtained in Russia in 1931. Professor S.V. Lebedev opened the economical method of producing ethyl alcohol butadiene and carried out the polymerization of butadiene on a radical mechanism in the presence of metal sodium: ...

Fructose - isomer glucose, contained together with glucose in sweet fruits and honey. She is sweetering glucose and sucrose. Fructose is a ketonospirt. The structure of its molecule can be expressed by the formula with hydroxyl groups, fructose, like glucose, is able to form sugars and esters. However, due to the lack of an aldehyde group, it is less susceptible to oxidation than glucose. Fructose, so ...

Heterocyclic compounds - organic compounds containing in their cycles molecules in which non-expensive atoms (heteroatoms) take part. Heterocyclic compounds are classified according to the number of atoms in the cycle and by the type of heteroatom. In this chapter, we will consider only some nitrogen-containing heterocycles, derivatives of which have an important biochemical value. Six-membered pyridine heterocycles C5H5N - the simplest six-membered aromatic heterocycle with ...

From the group of disaccharides, a sucrose is the greatest importance, which is otherwise called beet or cane sugar. Empirical formula of sucrose C12N22O11. Great content of sucrose in sugar beet and in sugar cane stems. It also is also in the juice of birch, maple, in many fruits and vegetables. Sakharoza (ordinary sugar) - white crystalline substance, sweetest than glucose, well soluble in ...

The chemical properties of pyridine are determined by the presence of an aromatic system and a nitrogen atom with a mean-free electronic pair. 1. Basic properties. Pyridine is a weaker base than aliphatic amines (KB \u003d 1.7.10-9). Its aqueous solution stains a lactum in blue: in the interaction of pyridine with strong acids, pyridine salts are formed: 2. Aromatic properties. Like benzene, pyridine enters the reaction of the electrophile ...

All substances that contain a carbon atom, in addition to carbonates, carbides, cyanides, thiocyondas and coalic acid, are organic compounds. This means that they are able to be created by alive organisms from carbon atoms by enzymatic or other reactions. To date, many organic substances can be synthesized artificially, which allows to develop medicine and pharmacology, as well as create high-strength polymer and composite materials.

Classification of organic compounds

Organic compounds are the most numerous class of substances. There are about 20 species of substances. They are different in chemical properties, are characterized by physical qualities. Their melting point, weight, volatility and solubility, as well as the aggregate state under normal conditions are also different. Among them:

• hydrocarbons (alkanes, alkins, alkenes, alkadians, cycloalkanes, aromatic hydrocarbons);
• aldehydes;
• ketones;
• alcohols (diatomic, monoatomic, polyatomic);
• ethers;
• esters;
• carboxylic acids;
• amines;
• amino acids;
• carbohydrates;
• fats;
• proteins;
• biopolymers and synthetic polymers.

This classification reflects the peculiarities of the chemical structure and the presence of specific atomic groups that determine the difference in the properties of a substance. In general, the classification, which is based on a carbon skeleton configuration that does not take into account the characteristics of chemical interactions, it looks different. Accordingly, its provisions, organic compounds are divided into:

• aliphatic compounds;
• aromatic substances;
• heterocyclic substances.

These classes of organic compounds may have isomers in different groups of substances. The properties of isomers are different, although their atomic composition may be the same. This follows from the provisions laid by A. M. Butlerov. Also, the theory of the structure of organic compounds is a guidance on all studies in organic chemistry. It put for one level with the Mendeleev periodic law.

The very concept of the chemical structure was introduced by A. M. Butlers. In the history of chemistry it appeared on September 19, 1861. Earlier, there were various opinions in science, and some of the scientists denied the presence of molecules and atoms at all. Therefore, there was no order in organic and inorganic chemistry. Moreover, there were no regularities for which it was possible to judge the properties of specific substances. At the same time there were connections that with the same composition showed different properties.

The assertions of A. M. Butlerova largely sent the development of chemistry into the right channel and created a strongest foundation for it. Through it managed to systematize the accumulated facts, namely, the chemical or physical properties of some substances, the patterns of their entry into the reaction and so on. Even the prediction of ways to produce compounds and the presence of some common properties has become possible due to this theory. And the main thing, A. M. Butlers showed that the structure of the substance molecule can be explained from the point of view of electrical interactions.

Logic of the theory of the structure of organic substances

Since until 1861 in chemistry, many rejected the existence of an atom or molecule, the theory of organic compounds became a revolutionary proposal for the scientist. And since the Bootler himself A. M. It comes only from materialistic conclusions, he managed to refute the philosophical ideas about the Organic.

He managed to show that the molecular structure can be recognized by experimentally by chemical reactions. For example, the composition of any carbohydrate can be founded by burning its definite amount and calculation of the resulting water and carbon dioxide. The amount of nitrogen in the amine molecule is also calculated when burning by measuring the volume of gases and isolating the chemical amount of molecular nitrogen.

If we consider the judgments of Butlerov about the chemical structure, depending on the structure, in the opposite direction, the new conclusion suggests itself. Namely: Knowing the chemical structure and composition of the substance, one can empirically assume its properties. But the most important thing - Butlers explained that a huge amount of substances occur in the organizing agent, but having the same composition.

General provisions of the theory

Considering and exploring organic compounds, Bootlers A. M. brought some of the most important patterns. He combined them into the situation of the theory explaining the structure of chemicals of organic origin. The situation of the theory is:

• in organic substances molecules, atoms are interconnected in a strictly defined sequence, which depends on valence;
• the chemical structure is an immediate order according to which atoms in organic molecules are connected;
• the chemical structure determines the presence of the properties of the organic compound;
• depending on the structure of molecules with the same quantitative composition, the appearance of various properties of the substance;
• all atomic groups involved in the formation of a chemical compound have a mutual influence on each other.

All classes of organic compounds are built according to the principles of this theory. Having laid the foundations, Butlers A. M. was able to expand the chemistry as the science area. He explained that due to the fact that in organic substances, carbon exhibits valence equal to four, the diversity of these compounds is caused by a variety. The presence of a plurality of active atomic groups determines the belonging of the substance to a specific class. And precisely through the presence of specific atomic groups (radicals), physical and chemical properties appear.

Hydrocarbons and their derivatives

These organic compounds of carbon and hydrogen are the most simple in composition among all substances of the group. They are represented by the subclass of alkanans and cycloalkanes (saturated hydrocarbons), alkenes, alkadiennes and alkatrines, alkins (unsaturated hydrocarbons), as well as a subclass of aromatic substances. In alkanes, all carbon atoms are connected only to a single C-with bond, which is why no atom N. can not be built into the composition of the hydrocarbon

In unsaturated hydrocarbons, hydrogen can be embedded at the place of presence double C \u003d due to communication. Also, the C-s connection may be triple (alkina). This allows these substances to enter into a variety of reactions associated with the restoration or addition of radicals. All other substances for the convenience of studying their ability to enter into reactions are treated as derivatives of one of the classes of hydrocarbons.

Alcohol

Alcohols are called more complex than hydrocarbons organic chemical compounds. They are synthesized as a result of the flow of enzymatic reactions in living cells. The most typical example is the synthesis of ethanol from glucose as a result of fermentation.

In industry, alcohols are obtained from halogen derivatives of hydrocarbons. As a result of replacing the halogen atom on the hydroxyl group and alcohols are formed. Singoatomic alcohols contain only one hydroxyl groups, polyatomic - two or more. An example of two-heed alcohol is ethylene glycol. Polyatomic alcohol is glycerin. The general formula of alcohols R-OH (R is carbon chain).

Aldehydes and Ketones

After the alcohols come into the reaction of organic compounds associated with the dumping of hydrogen from the alcohol (hydroxyl) group, the double bond between oxygen and carbon is closed. If this reaction passes along an alcohol group located at a terminal carbon atom, then the result is formed by aldehyde. If a carbon atom with alcohol is located not at the end of the carbon chain, then the result of the dehydration reaction is to obtain a ketone. The general formula of ketones is R-CO-R, Aldehydes R-COH (R - hydrocarbon radical chain).

Esters (simple and complex)

The chemical structure of organic compounds of this class complicated. Simple esters are treated as reaction products between two alcohol molecules. When the water is cleaned from them, the connection of the R-O-R sample is formed. Reaction mechanism: cleavage of hydrogen proton from one alcohol and hydroxyl group from another alcohol.

Painting esters - reaction products between alcohol and organic carboxylic acid. Reaction mechanism: water cleaner from alcohol and carbon group of both molecules. The hydrogen is cleaved from the acid (by hydroxyl group), and the group itself is separated from alcohol. The resulting compound is depicted as R-CO-O-R, where the bucken R is indicated by the radicals - the remaining portions of the carbon chain.

Carboxylic acids and amines

Carboxylic acids are characterized by special substances that play an important role in the functioning of the cell. The chemical structure of organic compounds is: hydrocarbon radical (R) with a carboxyl group attached to it (-son). The carboxyl group can be located only at the extreme carbon atom, because valence C in group (-son) is equal to 4.

Amines are simpler compounds that are hydrocarbon derivatives. Here, any carbon atom has amine radical (-NH2). There are primary amines in which the group (-nh2) joins one carbon (the general formula R-NH2). In secondary amines, nitrogen is connected with two carbon atoms (formula R-NH-R). In tertiary amines, nitrogen is connected to three carbon atoms (R3N), where R radical, carbon chain.

Amino acids

Amino acids - complex compounds that exhibit properties and amines, and acids of organic origin. There are several of their species depending on the location of the amine group with respect to carboxyl. The most important alpha-amino acids. Here the amine group is located at the carbon atom, to which carboxyl is attached. This allows you to create a peptide bond and synthesize proteins.

Carbohydrates and fats

Carbohydrates are aldehydospirts or ketospirts. These are compounds with a linear or cyclic structure, as well as polymers (starch, cellulose and other). Their essential role in the cell is structural and energy. Fats, or rather lipids, perform the same functions, only participate in other biochemical processes. From the point of view of the chemical structure, fat is ester organic acids and glycerin.

Organic Chemistry - Science, which studies carbon compounds with other elements, called organic compounds, as well as the laws of their transformations. The name "Organic Chemistry" originated at an early stage of development of science, when the subject of study was limited to the compounds of carbon of plant and animal origin. Not all carbon compounds can be called organic. For example, CO 2, HCN, CS 2 traditionally refer to inorganic. It can be conventionally assumed that the prototype of organic compounds is methane CH 4.

To date, the number of known organic substances exceeds 10 million and increases each year by 200-300 thousand. The variety of these compounds is determined by the unique ability of carbon atoms to connect with simple and multiple connections, to form compounds with a practically unlimited number of atoms associated in the chain, Cycles, frames, etc., to form strong links with almost all elements of the periodical system, as well as the phenomenon of isomerism - the existence of the same in composition, but different in the structure and properties of substances.

A huge number of organic compounds determines the level of org. Chemistry as the largest section of modern chemistry. The world around us is built mainly from the org. compounds; Food, fuel, clothing, medicines, paints, detergents, materials, without which it is impossible to create transport, typography, penetration into space and so on. The most important role of the Org. The compounds play in the processes of vital activity. The magnitude of the Molecules of the Org. Substances are divided into low molecular weight (with a molar mass of several dozen to several hundred, rare up to thousands) and high molecular weight (macromolecular; with a molar mass of about 10 4 -10 6 or more).

Organic chemistry studies not only compounds obtained from plant and animal organisms, but mainly compounds created artificially with a laboratory or industrial organic synthesis. Moreover, the objects of studying a computer org. Chemistry are compounds that are not only not existing in living organisms, but which, apparently, cannot be obtained artificially (for example, a hypothetical analogue of methane, which has a non-natural tetrahedral structure, but the shape of a flat square).

Historical reference

The origins of organic chemistry go back to deep antiquity (already then knew about alcohol and acetic acid fermentation, the collapse of Indigo and Alizarin). However, only a few individual org were known in the Middle Ages (Alchemy period). Substances. All studies of this period have completed mainly to operations, with the help of which, as they thought, one simple substances can be turned into others. Starting with the XVI century. (The period of yatrochimia) studies were directed mainly to the release and use of various medicinal substances: a number of essential oils were isolated from plants, diethyl ether was prepared, wood distillation was obtained wood (methyl) alcohol and acetic acid, from wine stone - Wine acid, distillation Lead sugar - acetic acid, distillation of amber - amber.

The merger of chemical compounds of plant and animal origin in a single chemical. Science org. Chemistry implemented J. Berzelius, who introduced the term and the concept of organic matter, the formation of the latter, according to Burtsellius, possibly only in a living organism in the presence of "vitality".

This error refuted F. Völer (1828), which was obtained by urea (Org. Substance) from ammonium cyanate (inorganic substance), A. Kolbe, Synthesizing acetic acid, M. Bertlo, received methane from H 2 S and CS 2, AM Butlers , Synthesizing sugar substances from formalin. In the first floor. XIX century An extensive experienced material was accumulated and the first generalizations were made, identifying the rapid development of the Org. Chemistry: ADD analysis methods. compounds (Britzelius, Y. Lubih, J. Duma, M. Shevreyl), created the theory of radicals (Vyler, J. Gay-Loussak, Lubi, Duma) as groups of atoms, passing unchanged from the initial molecule to the final in the reaction process; Type Theory (Sh. Gerard, 1853), in which Org. The compounds were designed from inorganic substances - "types" by replacing atoms in them on org. fragments; The concept of isomerism (Britzelius) was introduced.

At the same time, the intensive development of synthesis continues. The first industrial production are created organic compounds (A. Gofman, W. Perkin-senior - Synthetic dyes: Movein, Fucin, cyanin and azocracy). Improving Open N. N. Zinin (1842) The method of synthesis of aniline served as the basis for creating aniline-painting industry.

The idea of \u200b\u200ban inseparable coup. and Piz. The properties of the molecule with its structure, the idea of \u200b\u200bthe uniqueness of this structure was first expressed by Butlerov (1861), which created the classical theory of Chem. The buildings (atoms in molecules are connected according to their valenneys, chemical. and physical properties of the compound are determined by the nature and number of atoms included in their composition, as well as the type of bonds and mutual influence of directly unbound atoms). Theory Chem. Building has determined the further rapid development of organic chemistry: in 1865, Kekule proposed the formula of benzene, later expressed the idea of \u200b\u200boscillation of ties; V.V. Markovnikov and A.M. Zaitsev formulated a number of rules, first tied the direction of Him. Reactions with chemical. The structure of the reaction substance.

Works by Bayer, K. Laara, L. Claisen, L. Knorra Development tautomeria -movable isomeria. All these theoretical ideas contributed to the powerful development of synthetic chemistry. To con. XIX century All the most important representatives of hydrocarbons, alcohols, aldehydes and ketones, carboxylic acids, halogen and nitro-producing, nitrogen and sulfur-containing structures, aromatic heterocycles were obtained. Methods for obtaining dienes, acetylenes and allenov (A.E. Favorsky) have been developed. Numerous condensation reactions (S. Würz, A. P. Borodin, W. Perkin, Claisen, A. Michael, Sh. Freshene, J. Krafts, E. Knövenagel, etc.). Exceptional successes were achieved by E. G. Fisher in the study of carbohydrates, proteins and purines, in the use of enzymes in the Org. Synthesis (1894), they also carried out the synthesis of polypeptides. The basis of the industry of fragrant substances becomes the work of O. Wallach in the chemistry of terpenes. Outstanding even for our time are the pioneer works of R. Wilshtetter. Fundamental contribution to the development of the Org. The synthesis was introduced by V. Grignar (1900-20) and N.D. Zelinsky (1910) - the creation of an exceptionally fruitful method for the synthesis of magnesium organic compounds and the discovery of catalytic conversion of hydrocarbons; The latter played an outstanding role in the development of oil chemistry. The chemistry of free radicals began with the works of M. Gomberg (1900), which opened the triphenylmethyl radical, and was continued by the works of A. E. Chichibabin, Viland and Sh. Goldshmidt.

The structure of organic compounds

For organic compounds are characterized by non-polar covalent bonds of C-C and polar covalent bonds C-O, C-N, C-HAL, C-Metal, etc. The formation of covalent ties was explained on the basis of the assumptions developed by G. Lewis and V. Kossel (1916) on the important role of electronic formations - octets and doublets. The molecule is stable if the valence shell of such elements, as C, N, O, HAL, contains 8 electrons (octet rule), and the hydrogen valence sheath is 2 electrons. Chem. Communication is formed by a common pair of electrons of different atoms (simple communication). Double and triple bonds are formed by the corresponding two and three pairs. Electric negative atoms (F, O, N) are used to communicate with carbon not all their valence electrons; "Unused" electrons form outlined (free) electronic pairs. Polarity and polarizability of covalent ties in the org. The compounds in the Lewis - Kossel electronic theory is explained by the displacement of electronic pairs from the less electronegative to a more electronegative atom, which finds an expression in the inductive effect and the mesomeric effect.

Classical Him theory. Buildings and initially electronic representations were not able to satisfactorily describe in the language of structural formulas structure of many compounds, for example, aromatic. Modern communication theory in org. The compounds are based mainly on the concept of orbitals and uses methods of molecular orbitals. The quantumochemical methods are intensively developing, the objectivity of which is determined by the fact that they are based on the apparatus of quantum mechanics, the only suitable for studying the phenomena of the microworld.

The emergence of organic compounds

Most organic compounds in nature are formed in the process of photosynthesis of carbon dioxide and water under the action of solar radiation absorbed by chlorophyll in green plants. However org. The compounds had to exist on Earth and before the occurrence of life, which could not appear without them. The primary earthly atmosphere about 2 billion years ago had rehabilitation properties, since there was no oxygen in it, but first of all the hydrogen and water, as well as Co, nitrogen, ammonia and methane.

In conditions of strong radioactive radiation of earth minerals and intensive atmospheric discharges in the atmosphere, abiotic synthesis of amino acids according to the scheme flowed:

CH 4 + H 2 O + NH 3 → Amino Acid

The possibility of such a reaction is currently proven by laboratory experiments.