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 preparing "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 grew 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.

SIBERIAN POLYTECHNICAL COLLEGE

STUDENT HANDBOOK

in ORGANIC CHEMISTRY

for specialties of technical and economic profiles

Compiled by: teacher

2012

Structure "STUDENT'S HANDBOOK on ORGANIC CHEMISTRY"

EXPLANATORY NOTE

The SS in organic chemistry is designed to assist students in creating a scientific picture of the world through chemical content, taking into account interdisciplinary and intradisciplinary connections, the logic of the educational process.

The SS in organic chemistry presents the minimum in terms of volume, but functionally complete content for the development of the state standard chemical education.

The CC in Organic Chemistry performs two main functions:

I. The information function allows participants in the educational process to get an idea of ​​the content, structure of the subject, the relationship of concepts through diagrams, tables and algorithms.

II. The organizational and planning function provides for the allocation of training stages, the structuring of educational material, and creates ideas about the content of the intermediate and final certification.

SS involves the formation of a system of knowledge, skills and methods of activity, develops the ability of students to work with reference materials.

CHRONOLOGICAL TABLE "DEVELOPMENT OF ORGANIC CHEMISTRY"

MAIN PROVISIONS

THEORIES OF THE STRUCTURE OF ORGANIC COMPOUNDS

A. M. Butlerova

1. A. in M. are connected in a certain sequence, according to their valency.

2. The properties of substances depend not only on the qualitative and quantitative composition, but also on the chemical structure. Isomers. Isomerism.

3. A. and A. groups mutually influence each other.

4. By the properties of a substance, you can determine the structure, and by the structure - properties.

Isomers and homologues.

TSOS value

1. Explained the structure of M. known substances and their properties.

2. Made it possible to foresee the existence of unknown substances and find ways to synthesize them.

3. Explain the diversity of organic substances.

Classification of hydrocarbons.

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homologous series

ALKANE (LIMITED HYDROCARBONS)

homologous series

RADICALS FORMATED FROM ALKANE

General information about hydrocarbons.

DIV_ADBLOCK31">

Chemical properties of alkanes

(saturated hydrocarbons).

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Chemical properties of alkynes

(acetylenic hydrocarbons).

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Genetic link between hydrocarbons.

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MOLECULAR WEIGHTS OF SOME ORGANIC SUBSTANCES.

Problem solving algorithm

1. Study the conditions of the problem carefully: determine with what quantities the calculations are to be carried out, designate them with letters, set their units of measurement, numerical values, determine which value is the desired one.

2. Write down these tasks in the form of brief conditions.

3. If in the conditions of the problem we are talking about the interaction of substances, write down the equation of the reaction (reactions) and equalize it (their) coefficients.

4. Find out the quantitative relationships between the data of the problem and the desired value. To do this, divide your actions into stages, starting with the question of the problem, finding out the patterns with which you can determine the desired value at the last stage of calculations. If the initial data lacks any values, think about how they can be calculated, i.e., determine the preliminary stages of the calculation. There may be several of these steps.

5. Determine the sequence of all stages of solving the problem, write down the necessary calculation formulas.

6. Substitute the corresponding numerical values ​​of the quantities, check their dimensions, and perform calculations.

Derivation of compound formulas.

This type of calculation is extremely important for chemical practice, since it allows, on the basis of experimental data, to determine the formula of a substance (simple and molecular).

Based on the data of qualitative and quantitative analyzes, the chemist first finds the ratio of atoms in a molecule (or other structural unit of a substance), that is, its simplest formula.
For example, the analysis showed that the substance is a hydrocarbon
CxHy, in which the mass fractions of carbon and hydrogen are respectively equal to 0.8 and 0.2 (80% and 20%). To determine the ratio of atoms of elements, it is enough to determine their amounts of matter (number of moles): Integer numbers (1 and 3) are obtained by dividing the number 0.2 by the number 0.0666. The number 0.0666 will be taken as 1. The number 0.2 is 3 times greater than the number 0.0666. So CH3 is the simplest the formula for this substance. The ratio of C and H atoms, equal to 1:3, corresponds to an innumerable number of formulas: C2H6, C3H9, C4H12, etc., but only one formula from this series is molecular for a given substance, i.e., reflecting the true number of atoms in its molecule. To calculate the molecular formula, in addition to the quantitative composition of a substance, it is necessary to know its molecular weight.

To determine this value, the relative gas density D is often used. So, for the above case, DH2 = 15. Then M(CxHy) = 15µM(H2) = 152 g/mol = 30 g/mol.
Since M(CH3) = 15, it is necessary to double the indices in the formula to match the true molecular weight. Hence, molecular substance formula: C2H6.

The definition of the formula of a substance depends on the accuracy of mathematical calculations.

When finding a value n element should take into account at least two decimal places and carefully round numbers.

For example, 0.8878 ≈ 0.89, but not 1. The ratio of atoms in a molecule is not always determined by simply dividing the resulting numbers by a smaller number.

by mass fractions of elements.

Task 1. Set the formula of a substance that consists of carbon (w=25%) and aluminum (w=75%).

Divide 2.08 by 2. The resulting number 1.04 does not fit an integer number of times in the number 2.78 (2.78:1.04=2.67:1).

Now let's divide 2.08 by 3.

In this case, the number 0.69 is obtained, which fits exactly 4 times in the number 2.78 and 3 times in the number 2.08.

Therefore, the x and y indices in the AlxCy formula are 4 and 3, respectively.

Answer: Al4C3(aluminum carbide).

Algorithm for finding the chemical formula of a substance

by its density and mass fractions of elements.

A more complex version of the tasks for deriving formulas of compounds is the case when the composition of a substance is given through the combustion products of these.

Task 2. When burning a hydrocarbon weighing 8.316 g, 26.4 g of CO2 was formed. The density of the substance under normal conditions is 1.875 g / ml. Find its molecular formula.

General information about hydrocarbons.

(continuation)

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Natural sources of hydrocarbons.

Oil - fossil, liquid fuel, a complex mixture of organic substances: saturated hydrocarbons, paraffins, naphthenes, aromatics, etc. Oil usually contains oxygen-, sulfur- and nitrogen-containing substances.

Oily liquid with a characteristic odor, dark in color, lighter than water. The most important source of fuel, lubricating oils and other petroleum products. The main (primary) processing process is distillation, as a result of which gasoline, naphtha, kerosene, solar oils, fuel oil, petroleum jelly, paraffin, and tar are obtained. Secondary recycling processes ( cracking, pyrolysis) make it possible to obtain additional liquid fuel, aromatic hydrocarbons (benzene, toluene, etc.), etc.

Petroleum gases - a mixture of various gaseous hydrocarbons dissolved in oil; they are released during extraction and processing. They are used as fuel and chemical raw materials.

Petrol- a colorless or yellowish liquid, consists of a mixture of hydrocarbons ( C5 - C11 ). It is used as motor fuel, solvent, etc.

Naphtha- transparent yellowish liquid, a mixture of liquid hydrocarbons. It is used as diesel fuel, solvent, hydraulic fluid, etc.

Kerosene- transparent, colorless or yellowish liquid with a blue tint. It is used as a fuel for jet engines, for household needs, etc.

Solar- a yellowish liquid. It is used for the production of lubricating oils.

fuel oil– heavy oil fuel, a mixture of paraffins. They are used in the production of oils, fuel oil, bitumen, for processing into light motor fuel.

Benzene It is a colorless liquid with a characteristic odour. It is used for the synthesis of organic compounds, as a raw material for the production of plastics, as a solvent, for the production of explosives, in the aniline-dye industry.

Toluene is an analogue of benzene. It is used in the production of caprolactam, explosives, benzoic acid, saccharin, as a solvent, in the aniline-dye industry, etc.

Lubricating oils- Used in various fields of technology to reduce friction fur. parts, to protect metals from corrosion, as a cutting fluid.

Tar- black resinous mass. Used for lubrication, etc.

Petrolatum- a mixture of mineral oil and paraffins. They are used in electrical engineering, for lubricating bearings, for protecting metals from corrosion, etc.

Paraffin- a mixture of solid saturated hydrocarbons. Used as an electrical insulator, in chem. industry - to obtain higher acids and alcohols, etc.

Plastic– materials based on macromolecular compounds. Used for the production of various technical products and household items.

asphalt ore- a mixture of oxidized hydrocarbons. It is used for the manufacture of varnishes, in electrical engineering, for asphalting streets.

mountain wax- a mineral from the group of petroleum bitumens. It is used as an electrical insulator, for the preparation of various lubricants and ointments, etc.

artificial wax- purified mountain wax.

Coal - solid fossil fuel of plant origin, black or black-gray. Contains 75–97% carbon. Used as a fuel and as a raw material for the chemical industry.

Coke- a sintered solid product formed when certain coals are heated in coke ovens to 900–1050° C. Used in blast furnaces.

coke oven gas– gaseous products of coking of fossil coals. Comprises CH4, H2, CO and others, also contains non-combustible impurities. It is used as a high-calorie fuel.

ammonia water- liquid product of dry distillation of coal. It is used to obtain ammonium salts (nitrogen fertilizers), ammonia, etc.

Coal tar- a thick dark liquid with a characteristic odor, a product of the dry distillation of coal. It is used as a raw material for chemical industry.

Benzene- a colorless mobile liquid with a characteristic odor, one of the products of coal tar. They are used for the synthesis of organic compounds, as explosives, as a raw material for the production of plastics, as a dye, as a solvent, etc.

Naphthalene- a solid crystalline substance with a characteristic odor, one of the products of coal tar. Naphthalene derivatives are used to obtain dyes and explosives, etc.

Medications- the coke industry produces a number of drugs (carbolic acid, phenacytin, salicylic acid, saccharin, etc.).

Pitch- a solid (viscous) mass of black color, the residue from the distillation of coal tar. It is used as a waterproofing agent, for the production of fuel briquettes, etc.

Toluene- analogue of benzene, one of the products of coal tar. Used for the production of explosives, caprolactam, benzoic acid, saccharin, as a dye, etc.

Dyes- one of the products of coke production, obtained as a result of the processing of benzene, naphthalene and phenol. Used in the national economy.

Aniline- colorless oily liquid, poisonous. It is used to obtain various organic substances, aniline dyes, various azo dyes, the synthesis of drugs, etc.

Saccharin- solid white crystalline substance of sweet taste, obtained from toluene. It is used instead of sugar for diabetes, etc.

BB- derivatives of coal obtained in the process of dry distillation. They are used in the military industry, mining and other sectors of the national economy.

Phenol- a crystalline substance of white or pink color with a characteristic strong odor. It is used in the production of phenol-formaldehyde plastics, nylon synthetic fiber, dyes, medicines, etc.

Plastic– materials based on macromolecular compounds. Used for the production of various technical products and household items.

Alkanes(saturated hydrocarbons, paraffins) - acyclic saturated hydrocarbons of the general formula C n H 2n+2 . In accordance with the general formula, alkanes form homologous series.

The first four representatives have semi-systematic names - methane (CH 4), ethane (C 2 H 6), propane (C 3 H 8), butane (C 4 H 10). The names of the subsequent members of the series are built from the root (Greek numerals) and the suffix - en: pentane (C 5 H 12), hexane (C 6 H 14), heptane (C 7 H 16), etc.

The carbon atoms in alkanes are in sp 3- hybrid state. axes four sp3- orbitals are directed to the vertices of the tetrahedron, the bond angles are 109°28.

Spatial structure of methane:

C-C bond energy E s - With\u003d 351 kJ / mol, the length of the C-C bond is 0.154 nm.

The C-C bond in alkanes is covalent non-polar. S-N connection - covalent weakly polar.

For alkanes, starting with butane, there are structural isomers(structure isomers) that differ in the order of binding between carbon atoms, with the same qualitative and quantitative composition and molecular weight, but differing in physical properties.

1. C n H 2n+2 > 400-700°C> С p H 2p+2 + С m H 2m ,

Oil cracking (industrial method). Alkanes are also isolated from natural sources (natural and associated gases, oil, coal).

(hydrogenation of unsaturated compounds)

3. nCO + (2n + 1)H 2 > C n H 2n+2 + nH 2 O (obtained from synthesis gas (CO + H 2))

4. (Wurtz reaction)

5. (Dumas reaction) CH 3 COONa + NaOH > t> CH 4 + Na 2 CO 3

6. (Kolbe reaction)

Alkanes are not capable of addition reactions, since all bonds in their molecules are saturated, they are characterized by reactions of radical substitution, thermal decomposition, oxidation, isomerization.

1. (reactivity decreases in the series: F 2 > Cl 2 > Br 2 > (I 2 does not go), R 3 C > R 2 CH > RCH 2 > RCH 3)

2. (Konovalov's reaction)

3. C n H 2n+2 + SO 2 + ?O 2 > h?> C n H 2n+1 SO 3 H - alkyl sulfonic acid

(sulfonic oxidation, reaction conditions: UV irradiation)

4.CH4> 1000°C> C + 2H 2; 2CH4> t>1500 °C> C 2 H 2 + ZN 2 (methane decomposition - pyrolysis)

5. CH 4 + 2H 2 O> Ni, 1300 °C> CO 2 + 4H 2 (methane conversion)

6. 2С n H 2n + 2 + (Зn + 1) O 2 > 2nCO 2 + (2n + 2) Н 2 O (burning of alkanes)

7. 2n- C 4 H 10 + 5O 2 > 4CH 3 COOH + 2H 2 O (oxidation of alkanes in industry; production of acetic acid)

8. n- C 4 H 10 > iso- C 4 H 10 (isomerization, AlCl 3 catalyst)

Cycloalkanes(cycloparaffins, naphthenes, cyclanes, polymethylenes) are saturated hydrocarbons with a closed (cyclic) carbon chain. General formula C n H 2n.

The carbon atoms in cycloalkanes, as in alkanes, are in sp 3-hybridized state. homologous series cycloalkanes begins with the simplest cycloalkane - cyclopropane C 3 H 6, which is a flat three-membered carbocycle. According to the rules of international nomenclature in cycloalkanes, the main chain of carbon atoms forming a cycle is considered. The name is built on the name of this closed chain with the addition of the prefix "cyclo" (cyclopropane, cyclobutane, cyclopentane, cyclohexane, etc.).

Structural isomerism of cycloalkanes is associated with different ring sizes (structures 1 and 2), structure and type of substituents (structures 5 and 6), and their mutual arrangement (structures 3 and 4).

1. Obtaining from dihalogen derivatives of hydrocarbons

2. Preparation from aromatic hydrocarbons

The chemical properties of cycloalkanes depend on the ring size, which determines its stability. Three- and four-membered cycles (small cycles), being saturated, differ sharply from all other saturated hydrocarbons. Cyclopropane, cyclobutane enter into addition reactions. For cycloalkanes (C 5 and above), due to their stability, reactions are characteristic in which the cyclic structure is preserved, i.e., substitution reactions.

1. Action of halogens

2. Action of hydrogen halides

Hydrogen halogens do not react with cycloalkanes containing five or more carbon atoms in the cycle.

4. Dehydrogenation

Alkenes(unsaturated hydrocarbons, ethylene hydrocarbons, olefins) - unsaturated aliphatic hydrocarbons, the molecules of which contain a double bond. The general formula for a number of alkenes C n H 2n.

According to the systematic nomenclature, the names of alkenes are derived from the names of the corresponding alkanes (with the same number of carbon atoms) by replacing the suffix – en on - en: ethane (CH 3 -CH 3) - ethene (CH 2 \u003d CH 2), etc. The main chain is chosen so that it necessarily includes a double bond. The numbering of carbon atoms starts from the end of the chain closest to the double bond.

In an alkene molecule, the unsaturated carbon atoms are in sp 2-hybridization, and the double bond between them is formed by?- and?-bond. sp 2-Hybrid orbitals are directed to each other at an angle of 120 °, and one unhybridized 2p-orbital, located at an angle of 90 ° to the plane of hybrid atomic orbitals.

Spatial structure of ethylene:

C=C bond length 0.134 nm, C=C bond energy E c=c\u003d 611 kJ / mol, energy?-bond E? = 260 kJ/mol.

Types of isomerism: a) chain isomerism; b) double bond position isomerism; V) Z, E (cis, trans) - isomerism, a type of spatial isomerism.

1. CH 3 -CH 3> Ni, t> CH 2 \u003d CH 2 + H 2 (dehydrogenation of alkanes)

2. C 2 H 5 OH >H,SO 4 , 170 °C> CH 2 \u003d CH 2 + H 2 O (dehydration of alcohols)

3. (dehydrohalogenation of alkyl halides according to the Zaitsev rule)

4. CH 2 Cl-CH 2 Cl + Zn > ZnCl 2 + CH 2 \u003d CH 2 (dehalogenation of dihalogen derivatives)

5. HC?CH + H2> Ni, t> CH 2 \u003d CH 2 (alkyne reduction)

For alkenes, addition reactions are most characteristic; they are easily oxidized and polymerized.

1. CH 2 \u003d CH 2 + Br 2\u003e CH 2 Br-CH 2 Br

(addition of halogens, qualitative reaction)

2. (addition of hydrogen halides according to the Markovnikov rule)

3. CH 2 \u003d CH 2 + H 2> Ni, t> CH 3 -CH 3 (hydrogenation)

4. CH 2 \u003d CH 2 + H 2 O> H+> CH 3 CH 2 OH (hydration)

5. ZCH 2 \u003d CH 2 + 2KMnO 4 + 4H 2 O\u003e ZCH 2 OH-CH 2 OH + 2MnO 2 v + 2KOH (mild oxidation, qualitative reaction)

6. CH 2 \u003d CH-CH 2 -CH 3 + KMnO 4> H+> CO 2 + C 2 H 5 COOH (hard oxidation)

7. CH 2 \u003d CH-CH 2 -CH 3 + O 3\u003e H 2 C \u003d O + CH 3 CH 2 CH \u003d O formaldehyde + propanal> (ozonolysis)

8. C 2 H 4 + 3O 2 > 2CO 2 + 2H 2 O (combustion reaction)

9. (polymerization)

10. CH 3 -CH \u003d CH 2 + HBr\u003e peroxide> CH 3 -CH 2 -CH 2 Br (addition of hydrogen bromide against Markovnikov's rule)

11. (substitution reaction in?-position)

Alkynes(acetylenic hydrocarbons) - unsaturated hydrocarbons that have a triple C?C bond in their composition. The general formula of alkynes with one triple bond is C n H 2n-2. The simplest representative of the CH?CH series of alkynes has the trivial name acetylene. According to the systematic nomenclature, the names of acetylenic hydrocarbons are derived from the names of the corresponding alkanes (with the same number of carbon atoms) by replacing the suffix - en on -in: ethane (CH 3 -CH 3) - ethine (CH? CH), etc. The main chain is chosen so that it necessarily includes a triple bond. The numbering of carbon atoms starts from the end of the chain closest to the triple bond.

The formation of a triple bond involves carbon atoms in sp-hybridized state. Each of them has two sp- hybrid orbitals directed to each other at an angle of 180 °, and two non-hybrid p orbitals at 90° to each other and to sp hybrid orbitals.

Spatial structure of acetylene:

Types of isomerism: 1) isomerism of the position of the triple bond; 2) isomerism of the carbon skeleton; 3) interclass isomerism with alkadienes and cycloalkenes.

1. CaO + GL > t> CaC 2 + CO;

CaC 2 + 2H 2 O > Ca (OH) 2 + CH? CH (production of acetylene)

2.2CH4> t>1500 °C> HC = CH + ZN 2 (hydrocarbon cracking)

3. CH 3 -CHCl 2 + 2KOH> in alcohol> HC?CH + 2KCl + H 2 O (dehalogenation)

CH 2 Cl-CH 2 Cl + 2KOH> in alcohol> HC?CH + 2KCl + H 2 O

Alkynes are characterized by addition, substitution reactions. Alkynes polymerize, isomerize, enter into condensation reactions.

1. (hydrogenation)

2. HC?CH + Br 2 > CHBr=CHBr;

CHBr \u003d CHBr + Br 2\u003e CHBr 2 -CHBr 2 (addition of halogens, qualitative reaction)

3. CH 3 -C? CH + HBr> CH 3 -CBr \u003d CH 2;

CH 3 -CBr \u003d CH 2 + HBr\u003e CH 3 -CBr 2 -CHg (addition of hydrogen halides according to the Markovnikov rule)

4. (hydration of alines, Kucherov's reaction)

5.(addition of alcohols)

6.(attaching carbon islot)

7.CH?CH + 2Ag2O> NH3> AgC?CAgv + H 2 O (formation of acetylenides, qualitative reaction for terminal triple bond)

8.CH?CH + [O]> KMnO 4> HOOC-COOH > HCOOH + CO 2 (oxidation)

9. CH?CH + CH?CH > CH 2 \u003d CH-C?CH (catalyst - CuCl and NH 4 Cl, dimerization)

10.3HC?CH> C, 600°C> C 6 H 6 (benzene) (cyclooligomerization, Zelinsky reaction)

Alkadienes(dienes) - unsaturated hydrocarbons, the molecules of which contain two double bonds. The general formula of alkadienes C n H 2n _ 2. The properties of alkadienes largely depend on the mutual arrangement of double bonds in their molecules.

1. (SV. Lebedev's method)

2. (dehydration)

3. (dehydrogenation)

For conjugated dienes, addition reactions are characteristic. Conjugated dienes are able to attach not only to double bonds (to C 1 and C 2, C 3 and C 4), but also to the terminal (C 1 and C 4) carbon atoms to form a double bond between C 2 and C 3.

arenas, or aromatic hydrocarbons,- cyclic compounds, the molecules of which contain stable cyclic groups of atoms with a closed system of conjugated bonds, united by the concept of aromaticity, which determines common features in the structure and chemical properties.

All C-C bonds in benzene are equivalent, their length is 0.140 nm. This means that in the benzene molecule there are no purely simple and double bonds between carbon atoms (as in the formula proposed in 1865 by the German chemist F. Kekule), and all of them are aligned (they are localized).

Benzene homologues are compounds formed by replacing one or more hydrogen atoms in a benzene molecule with hydrocarbon radicals (R): C 6 H 5 -R, R-C 6 H 4 -R. The general formula for the homologous series of benzene C n H 2n _ 6 (n> 6). Trivial names (toluene, xylene, cumene, etc.) are widely used for the names of aromatic hydrocarbons. Systematic names are built from the name of the hydrocarbon radical (prefix) and the word "benzene" (root): C 6 H 5 -CH 3 (methylbenzene), C 6 H 5 -C 2 H 5 (ethylbenzene). If there are two or more radicals, their position is indicated by the numbers of the carbon atoms in the ring to which they are attached. For disubstituted benzenes R-C 6 H 4 -R, another method of constructing names is also used, in which the position of the substituents is indicated before the trivial name of the compound with prefixes: ortho-(o-) - substituents of neighboring carbon atoms of the ring (1,2-); meta-(m-) - substituents through one carbon atom (1,3-); pair-(P-) - substituents on opposite sides of the ring (1,4-).

Types of isomerism (structural): 1) positions of substituents for di-, tri- and tetra-substituted benzenes (for example, o-, m- And P-xylenes); 2) a carbon skeleton in a side chain containing at least 3 carbon atoms; 3) substituents (R), starting with R=C 2 H 5 .

1. C 6 H 12 > Pt, 300 °C> С 6 Н 6 + ЗН 2 (dehydrogenation of cycloalkanes)

2. n- C 6 H 14 > Cr2O3, 300°C> C 6 H 6 + 4H 2 (dehydrocyclization of alkanes)

3. ZS 2 H 2 > C, 600 °C> C 6 H 6 (cyclotrimerization of acetylene, Zelinsky reaction)

By chemical properties, arenas differ from saturated and unsaturated hydrocarbons. For arenes, the most characteristic reactions proceed with the preservation of the aromatic system, namely, the substitution reactions of hydrogen atoms associated with the cycle. Other reactions (addition, oxidation), in which delocalized C-C bonds of the benzene ring are involved and its aromaticity is disturbed, go with difficulty.

1. C 6 H 6 + Cl 2> AlCl 3> C 6 H 5 Cl + HCl (halogenation)

2. C 6 H 6 + HNO 3 > H2SO4> C 6 H 5 -NO 2 + H 2 O (nitration)

3. C 6 H 6 > H2SO4> C 6 H 5 -SO 3 H + H 2 O (sulfonation)

4. C 6 H 6 + RCl> AlCl 3> C 6 H 5 -R + HCl (alkylation)

5. (acylation)

6. C 6 H 6 + ZN 2> t, Ni> C 6 H 12 cyclohexane (hydrogen addition)

7. (1,2,3,4,5,6-hexachlorocyclohexane, addition of chlorine)

8. C 6 H 5 -CH 3 + [O]> C 6 H 5 -COOH boiling with a solution of KMnO 4 (oxidation of alkylbenzenes)

halocarbons called derivatives of hydrocarbons in which one or more hydrogen atoms are replaced by halogen atoms.

1. CH 2 \u003d CH 2 + HBr\u003e CH 3 -CH 2 Br (hydrohalogenation of unsaturated hydrocarbons)

CH?CH + HCl > CH 2 \u003d CHCl

2. CH 3 CH 2 OH + РCl 5 > CH 3 CH 2 Cl + POCl 3 + HCl (preparation from alcohols)

CH 3 CH 2 OH + HCl > CH 3 CH 2 Cl + H 2 O (in the presence of ZnCl 2, t°C)

3. a) CH 4 + Cl 2 >hv> CH 3 Cl + HCl (halogenation of hydrocarbons)

Substitution and elimination reactions are of the greatest importance for compounds of this class.

1. CH 3 CH 2 Br + NaOH (aqueous solution) > CH 3 CH 2 OH + NaBr (formation of alcohols)

2. CH 3 CH 2 Br + NaCN > CH 3 CH 2 CN + NaBr (formation of nitriles)

3. CH 3 CH 2 Br + NH 3 > + Br - HBr- CH 3 CH 2 NH 2 (formation of amines)

4. CH 3 CH 2 Br + NaNO 2 > CH 3 CH 2 NO 2 + NaBr (formation of nitro compounds)

5. CH 3 Br + 2Na + CH 3 Br > CH 3 -CH 3 + 2NaBr (Wurtz reaction)

6. CH 3 Br + Mg > CH 3 MgBr (formation of organomagnesium compounds, Grignard reagent)

7. (dehydrohalogenation)

alcohols called derivatives of hydrocarbons, the molecules of which contain one or more hydroxyl groups (-OH) associated with saturated carbon atoms. The -OH group (hydroxyl, hydroxy group) is a functional group in the alcohol molecule. Systematic names are given by the name of the hydrocarbon with the addition of the suffix - ol and a number indicating the position of the hydroxyl group. The numbering is carried out from the end of the chain closest to the OH group.

According to the number of hydroxyl groups, alcohols are divided into monohydric (one -OH group), polyhydric (two or more -OH groups). Monohydric alcohols: methanol CH 3 OH, ethanol C 2 H 5 OH; dihydric alcohol: ethylene glycol (ethanediol-1,2) HO-CH 2 -CH 2 -OH; trihydric alcohol: glycerol (propanetriol-1,2,3) HO-CH 2 -CH(OH)-CH 2 -OH. Depending on which carbon atom (primary, secondary or tertiary) the hydroxy group is associated with, primary alcohols R-CH 2 -OH, secondary R 2 CH-OH, tertiary R 3 C-OH are distinguished.

According to the structure of the radicals associated with the oxygen atom, alcohols are divided into saturated, or alkanols (CH 3 CH 2 -OH), unsaturated, or alkenols (CH 2 \u003d CH-CH 2 -OH), aromatic (C 6 H 5 CH 2 - OH).

Types of isomerism (structural isomerism): 1) isomerism of the position of the OH group (starting from C 3); 2) carbon skeleton (starting from C 4); 3) interclass isomerism with ethers (for example, ethyl alcohol CH 3 CH 2 OH and dimethyl ether CH 3 -O-CH 3). The consequence of the polarity of the O-H bond and the presence of lone pairs of electrons on the oxygen atom is the ability of alcohols to form hydrogen bonds.

1. CH 2 \u003d CH 2 + H 2 O / H +\u003e CH 3 -CH 2 OH (alkene hydration)

2. CH 3 -CHO + H 2> t, Ni> C 2 H 5 OH (reduction of aldehydes and ketones)

3. C 2 H 5 Br + NaOH (aq.) > C 2 H 5 OH + NaBr (hydrolysis of halogen derivatives)

ClCH 2 -CH 2 Cl + 2NaOH (aq.) > HOCH 2 -CH 2 OH + 2NaCl

4. CO + 2H 2> ZnO, CuO, 250 °C, 7 MPa> CH 3 OH (methanol production, industry)

5. C 6 H 12 O 6 > yeast> 2C 2 H 5 OH + 2CO 2 (monose fermentation)

6. 3CH 2 \u003d CH 2 + 2KMnO 4 + 4H 2 O\u003e 3CH 2 OH-CH 2 OH - ethylene glycol+ 2KOH + 2MnO 2 (oxidation under mild conditions)

7. a) CH 2 \u003d CH-CH 3 + O 2\u003e CH 2 \u003d CH-CHO + H 2 O

b) CH 2 \u003d CH-CHO + H 2\u003e CH 2 \u003d CH-CH 2 OH

c) CH 2 \u003d CH-CH 2 OH + H 2 O 2\u003e HOCH 2 -CH (OH) -CH 2 OH (obtaining glycerol)

The chemical properties of alcohols are associated with the presence of the -OH group in their molecule. Alcohols are characterized by two types of reactions: C-O bond cleavage and O-H bond.

1. 2C 2 H 5 OH + 2Na > H 2 + 2C 2 H 5 ONa (formation of metal alcoholates Na, K, Mg, Al)

2. a) C 2 H 5 OH + NaOH? (does not work in aqueous solution)

b) CH 2 OH-CH 2 OH + 2NaOH> NaOCH 2 -CH 2 ONa + 2H 2 O

c) (qualitative reaction to polyhydric alcohols - the formation of a bright blue solution with copper hydroxide)

3. a) (formation of esters)

b) C 2 H 5 OH + H 2 SO 4 > C 2 H 5 -O-SO 3 H + H 2 O (in the cold)

4. a) C 2 H 5 OH + HBr> C 2 H 5 Br + H 2 O

b) C 2 H 5 OH + РCl 5 > C 2 H 5 Cl + POCl 3 + HCl

c) C 2 H 5 OH + SOCl 2 > C 2 H 5 Cl + SO 2 + HCl (replacement of the hydroxyl group by halogen)

5. C 2 H 5 OH + HOC 2 H 5 > H2SO4,<140 °C > C 2 H 5 -O-C 2 H 5 + H 2 O (intermolecular hydration)

6. C 2 H 5 OH> H2SO4, 170°C> CH 2 \u003d CH 2 + H 2 O (intramolecular hydration)

7. a) (dehydrogenation, oxidation of primary alcohols)

Phenols arene derivatives are called, in which one or more hydrogen atoms of the aromatic ring are replaced by hydroxyl groups. According to the number of hydroxyl groups in the aromatic ring, mono- and polyatomic (two- and three-atomic) phenols are distinguished. Trivial names are used for most phenols. Structural isomerism of phenols is associated with different positions of hydroxyl groups.

1. C 6 H 5 Cl + NaOH(p, 340°C) > C 6 H 5 OH + NaCl (alkaline hydrolysis of halocarbons)

2. (cumene method of obtaining)

3. C 6 H 5 SO 3 Na + NaOH (300–350°C) > C 6 H 5 OH + Na 2 SO 3 (alkaline melting of salts of aromatic sulfonic acids)

Phenols in most reactions on the O-H bond are more active than alcohols, since this bond is more polar due to the shift of the electron density from the oxygen atom towards the benzene ring (participation of the lone electron pair of the oxygen atom in the n-conjugation system). The acidity of phenols is much higher than that of alcohols.

For phenols, C-O bond cleavage reactions are not typical. The mutual influence of atoms in the phenol molecule is manifested not only in the behavior of the hydroxy group, but also in the greater reactivity of the benzene ring.

The hydroxyl group increases the electron density in the benzene ring, especially in ortho- And pair- positions (+ M effect of the OH group). For the detection of phenols, a qualitative reaction with iron(III) chloride is used. Monatomic phenols give a stable blue-violet color, which is associated with the formation of complex iron compounds.

1. 2C 6 H 5 OH + 2Na > 2C 6 H 5 ONa + H 2 (same as ethanol)

2. C 6 H 5 OH + NaOH > C 6 H 5 ONa + H 2 O (unlike ethanol)

C 6 H 5 ONa + H 2 O + CO 2 > C 6 H 5 OH + NaHCO 3 (phenol is a weaker acid than carbonic)

Phenols do not form esters in reactions with acids. For this, more reactive acid derivatives (anhydrides, acid chlorides) are used.

4. C 6 H 5 OH + CH 3 CH 2 OH> NaOH> C 6 H 5 OCH 2 CH 3 + NaBr (O-alkylation)

(interaction with bromine water, qualitative reaction)

6. (Nitration dilute HNO 3, nitration with conc. HNO 3 produces 2,4,6-trinitrophenol)

7. n C6H5OH+ n CH2O> n H 2 O + (-C 6 H 3 OH-CH 2 -) n(polycondensation, obtaining phenol-formaldehyde resins)

Aldehydes are compounds in which the carbonyl group

connected to a hydrocarbon radical and a hydrogen atom, and ketones- carbonyl compounds with two hydrocarbon radicals.

The systematic names of aldehydes are built on the name of the corresponding hydrocarbon with the addition of a suffix –al. The chain numbering starts from the carbonyl carbon atom. Trivial names are derived from the trivial names of those acids into which aldehydes are converted during oxidation: H 2 C \u003d O - methanal (formaldehyde, formaldehyde); CH 3 CH=O - ethanal (acetic aldehyde). The systematic names of ketones of a simple structure are derived from the names of the radicals with the addition of the word "ketone". In a more general case, the name of a ketone is constructed from the name of the corresponding hydrocarbon and the suffix -He; chain numbering starts from the end of the chain closest to the carbonyl group. Examples: CH 3 -CO-CH 3 - dimethyl ketone (propanone, acetone). Aldehydes and ketones are characterized by structural isomerism. Isomerism of aldehydes: a) isomerism of the carbon skeleton, starting from C 4; b) interclass isomerism. Isomerism of ketones: a) carbon skeleton (with C 5); b) positions of the carbonyl group (with C 5); c) interclass isomerism.

The carbon and oxygen atoms in the carbonyl group are in the state sp2- hybridization. The C=O bond is highly polar. The electrons of the C=O multiple bond are shifted to the electronegative oxygen atom, which leads to the appearance of a partial negative charge on it, and the carbonyl carbon atom acquires a partial positive charge.

1. a) (dehydrogenation, oxidation of primary alcohols)

b) (dehydrogenation, oxidation of secondary alcohols)

2. a) CH 3 CH 2 CHCl 2 + 2NaOH> in water> CH 3 CH 2 CHO + 2NaCl + H 2 O (hydrolysis of dihalogen derivatives)

b) CH 3 СCl 2 CH 3 + 2NaOH> in water> CH 3 COCH 3 + 2NaCl + H 2 O

3. (hydration of alkynes, Kucherov reaction)

4. (oxidation of ethylene to ethanal)

(methane oxidation to formaldehyde)

CH 4 + O 2 > 400-600°C NO> H 2 C \u003d O + H 2 O

For carbonyl compounds, reactions of various types are characteristic: a) addition to the carbonyl group; b) reduction and oxidation; c) condensation; e) polymerization.

1. (addition of hydrocyanic acid, formation of hydroxynitriles)

2. (addition of sodium hydrosulphite)

3. (recovery)

4. (formation of hemiacetals and acetals)

5. (interaction with hydroxolamine, formation of acetaldehyde oxime)

6. (formation of dihalogen derivatives)

7. (?-halogenation in the presence of OH?)

8. (albdol condensation)

9. R-CH \u003d O + Ag 2 O> NH3> R-COOH + 2Agv (oxidation, silver mirror reaction)

R-CH \u003d O + 2Cu (OH) 2\u003e R-COOH + Cu 2 Ov, + 2H 2 O (red precipitate, oxidation)

10. (ketone oxidation, severe conditions)

11. n CH 2 \u003d O\u003e (-CH2-O-) n paraforms n= 8-12 (polymerization)

carboxylic acids called organic compounds containing one or more carboxyl groups -COOH associated with a hydrocarbon radical. According to the number of carboxyl groups, acids are divided into: monobasic (monocarboxylic) CH 3 COOH (acetic), polybasic (dicarboxylic, tricarboxylic, etc.). According to the nature of the hydrocarbon radical, acids are distinguished: limiting (for example, CH 3 CH 2 CH 2 COOH); unsaturated (CH 2 \u003d CH (-COOH); aromatic (C 6 H 5 COOH).

The systematic names of acids are given by the name of the corresponding hydrocarbon with the addition of the suffix –new and the words "acid": HCOOH - methane (formic) acid, CH 3 COOH - ethanoic (acetic) acid. For carboxylic acids, the characteristic structural isomerism is: a) skeletal isomerism in the hydrocarbon radical (starting from C 4); b) interclass isomerism, starting from C 2 . Possible cis-trans isomerism in the case of unsaturated carboxylic acids. electron density? - bonds in the carbonyl group are shifted towards the oxygen atom. As a result, carbonyl carbon has a lack of electron density, and it attracts lone pairs of the oxygen atom of the hydroxyl group, as a result of which the electron density of the O-H bond shifts towards the oxygen atom, hydrogen becomes mobile and acquires the ability to split off in the form of a proton.

In an aqueous solution, carboxylic acids dissociate into ions:

R-COOH - R-COO? + H +

Solubility in water and high boiling points of acids are due to the formation of intermolecular hydrogen bonds.

1. CH 3 -CCl 3 + 3NaOH > CH 3 -COOH + 3NaCl + H 2 O (hydrolysis of trihalogen derivatives)

2. R-CHO + [O] > R-COOH (oxidation of aldehydes and ketones)

3. CH 3 -CH \u003d CH 2 + CO + H 2 O / H + > Ni, p, t> CH 3 -CH 2 -CH 2 -COOH (oxosynthesis)

4. CH 3 C?N + 2H 2 O / H + > CH 3 COOH + NH 4 (hydrolysis of nitriles)

5. CO + NaOH > HCOONa; 2HCOONa + H 2 SO 4 > 2HCOOH + Na 2 SO 4 (obtaining HCOOH)

Carboxylic acids exhibit high reactivity and react with various substances, forming a variety of compounds, among which functional derivatives are of great importance: esters, amides, nitriles, salts, anhydrides, halogen anhydrides.

1. a) 2CH 3 COOH + Fe > (CH 3 COO) 2 Fe + H 2 (formation of salts)

b) 2CH 3 COOH + MgO > (CH 3 COO) 2 Mg + H 2 O

c) CH 3 COOH + KOH > CH 3 COOK + H 2 O

d) CH 3 COOH + NaHCO 3 > CH 3 COONa + CO 2 + H 2 O

CH 3 COONa + H 2 O - CH 3 COOH + NaOH (salts of carboxylic acids are hydrolyzed)

2. (formation of nested esters)

(saponification of nested ether)

3. (obtaining acid chlorides)

4. (water decomposition)

5. CH 3 -COOH + Cl 2> hv> Cl-CH 2 -COOH + HCl (halogenation in?-position)

6. HO-CH \u003d O + Ag 2 O> NH3> 2Ag + H 2 CO 3 (H 2 O + CO 2) (HCOOH features)

HCOOH > t> CO + H 2 O

Fats- esters of glycerol and higher monohydric carboxylic acids. The common name for these compounds is triglycerides. The composition of natural triglycerides includes residues of saturated acids (palmitic C 15 H 31 COOH, stearic C 17 H 35 COOH) and unsaturated acids (oleic C 17 H 33 COOH, linoleic C 17 H 31 COOH). Fats consist mainly of triglycerides of saturated acids. Vegetable fats - oils (sunflower, soybean) - liquids. The composition of triglycerides of oils includes residues of unsaturated acids.

Fats as esters are characterized by a reversible hydrolysis reaction catalyzed by mineral acids. With the participation of alkalis, the hydrolysis of fats occurs irreversibly. The products in this case are soaps - salts of higher carboxylic acids and alkali metals. Sodium salts are solid soaps, potassium salts are liquid. The reaction of alkaline hydrolysis of fats is also called saponification.

Amines- organic derivatives of ammonia, in the molecule of which one, two or three hydrogen atoms are replaced by hydrocarbon radicals. Depending on the number of hydrocarbon radicals, primary RNH 2 , secondary R 2 NH, tertiary R 3 N amines are distinguished. According to the nature of the hydrocarbon radical, amines are divided into aliphatic (fatty), aromatic and mixed (or fatty-aromatic). The names of amines in most cases are formed from the names of hydrocarbon radicals and the suffix -amine. For example, CH 3 NH 2 is methylamine; CH 3 -CH 2 -NH 2 - ethylamine. If the amine contains various radicals, then they are listed in alphabetical order: CH 3 -CH 2 -NH-CH 3 - methylethylamine.

The isomerism of amines is determined by the number and structure of radicals, as well as the position of the amino group. The N-H bond is polar, so primary and secondary amines form intermolecular hydrogen bonds. Tertiary amines do not form associated hydrogen bonds. Amines are capable of forming hydrogen bonds with water. Therefore, lower amines are highly soluble in water. With an increase in the number and size of hydrocarbon radicals, the solubility of amines in water decreases.

1. R-NO 2 + 6 [H] > R-NH 2 + 2H 2 O (reduction of nitro compounds)

2. NH 3 + CH 3 I > I? > NH3> CH 3 NH 2 + NH 4 I (ammonia alkylation)

3. a) C 6 H 5 -NO 2 + 3 (NH 4) 2 S> C 6 H 5 -NH 2 + 3S + 6NH 3 + 2H 2 O (Zinin reaction)

b) C 6 H 5 -NO 2 + 3Fe + 6HCl> C 6 H 5 -NH 2 + 3FeCl 2 + 2H 2 O (reduction of nitro compounds)

c) C 6 H 5 -NO 2 + ZN 2> catalyst, t> C 6 H 5 -NH 2 + 2H 2 O

4. R-C?N + 4[H]> RCH 2 NH 2 (reduction of nitriles)

5. ROH + NH 3 > Al 2 O 3 ,350 °C> RNH 2 + 2H 2 O (obtaining lower alkylamines C 2 -C 4)

Amines have a structure similar to ammonia and exhibit similar properties. In both ammonia and amines, the nitrogen atom has a lone pair of electrons. Amines are characterized by pronounced basic properties. Aqueous solutions of aliphatic amines exhibit an alkaline reaction. Aliphatic amines are stronger bases than ammonia. Aromatic amines are weaker bases than ammonia, since the unshared electron pair of the nitrogen atom is shifted towards the benzene ring, conjugating with its ?-electrons.

The basicity of amines is influenced by various factors: the electronic effects of hydrocarbon radicals, the spatial shielding of the nitrogen atom by radicals, and the ability of the resulting ions to stabilize due to solvation in a solvent medium. As a result of the donor effect of alkyl groups, the basicity of aliphatic amines in the gas phase (without solvent) increases in the series: primary< вторичные < третичные. Основность ароматических аминов зависит также от характера заместителей в бензольном кольце. Электроноакцепторные заместители (-F, -Cl, -NO 2 и т. п.) уменьшают основные свойства ариламина по сравнению с анилином, а электронодонорные (алкил R-, -OCH 3 , -N(CH 3) 2 и др.), напротив, увеличивают.

1. CH 3 -NH 2 + H 2 O> OH (interaction with water)

2. (CH 3) 2 NH + HCl > [(CH 3) 2 NH 2] Cl dimethylammonium chloride (reaction with acids)

[(CH 3) 2 NH 2] Cl + NaOH > (CH 3) 2 NH + NaCl + H 2 O (reaction of amine salts with alkalis)

(acylation, does not work with tertiary amines)

4. R-NH 2 + CH 3 I> I? > NH3> CH 3 NHR + NH 4 I (alkylation)

5. Interaction with nitrous acid: the structure of the reaction products with nitrous acid depends on the nature of the amine. Therefore, this reaction is used to distinguish between primary, secondary and tertiary amines.

a) R-NH 2 + HNO 2 > R-OH + N 2 + H 2 O (primary fatty amines)

b) C 6 H 5 -NH 2 + NaNO 2 + HCl> [C 6 H 5 -N? N] + Cl? – diazonium salt (primary aromatic amines)

c) R 2 NH + H-O-N \u003d O\u003e R 2 N-N \u003d O (N-nitrosamine) + H 2 O (secondary fatty and aromatic amines)

d) R 3 N + H-O-N \u003d O\u003e no reaction at low temperature (tertiary fatty amines)

(tertiary aromatic amines)

properties of aniline. Aniline is characterized by reactions both at the amino group and at the benzene ring. The benzene ring weakens the basic properties of the amino group compared to aliphatic amines and ammonia, but under the influence of the amino group, the benzene ring becomes more active in substitution reactions compared to benzene.

C 6 H 5 -NH 2 + HCl > Cl \u003d C 6 H 5 NH 2 HCl

C 6 H 5 NH 2 HCl + NaOH > C 6 H 5 NH 2 + NaCl + H 2 O

C 6 H 5 NH 2 + CH3I > t> +I?

Amino acids called hetero-functional compounds, the molecules of which contain both an amino group and a carboxyl group. Depending on the mutual arrangement of the amino and carboxyl groups, amino acids are divided into amino-, indicating the number of the carbon atom to which it is bonded, followed by the name of the corresponding acid.

By the nature of the hydrocarbon radical, aliphatic (fatty) and aromatic amino acids are distinguished. The isomerism of amino acids depends on the structure of the carbon skeleton, the position of the amino group in relation to the carboxyl group. Amino acids are also characterized by optical isomerism.

1. (ammonolysis of halogen acids)

2. CH 2 \u003d CH-COOH + NH 3 > H 2 N-CH 2 -CH 2 -COOH (ammonia addition to ?, ?-unsaturated acids)

(action of HCN and NH 3 on aldehydes or ketones)

4. Hydrolysis of proteins under the influence of enzymes, acids or alkalis.

5. Microbiological synthesis.

Amino acids exhibit the properties of bases due to the amino group and the properties of acids due to the carboxyl group, that is, they are amphoteric compounds. In the crystalline state and in an environment close to neutral, amino acids exist in the form of an internal salt - a dipolar ion, also called the zwitterion H 3 N + -CH 2 -COO?.

1. H 2 N-CH 2 -COOH + HCl> Cl? (formation of salts at the amino group)

2. H 2 N-CH 2 -COOH + NaOH> H 2 N-CH 2 -COO? Na + + H 2 O (formation of salts)

(ester formation)

(acylation)

5. + NH 3 -CH 2 -COO? + 3CH 3 I > -HI> (CH 3) 3 N + -CH 2 -COO? – aminoacetic acid betaine

(alkylation)

(interaction with nitrous acid)

7. n H 2 N-(CH 2) 5 -COOH> (-HN-(CH 2) 5 -CO-) n+ n H 2 O (obtaining capron)

Carbohydrates(sugar) - organic compounds having a similar structure and properties, the composition of most of which is reflected by the formula С x (Н 2 O) y, where x, y? 3.

Classification:

Monosaccharides are not hydrolyzed to form simpler carbohydrates. Oligo- and polysaccharides are cleaved by acid hydrolysis to monosaccharides. Well-known representatives: glucose (grape sugar) C 6 H 12 O 6, sucrose (cane, beet sugar) C 12 H 22 O 11, starch and cellulose [C 6 H 10 O 5] n.

1. mCO 2 + nH 2 O > hv, chlorophyll> C m (H 2 O) n (carbohydrates) + mO 2 (obtained by photosynthesis)

carbohydrates: C 6 H 12 O 6 + 6O 2 > 6CO 2 + 6H 2 O + 2920 kJ

(metabolism: glucose is oxidized with the release of a large amount of energy in a living organism during metabolism)

2. 6nCO 2 + 5nH 2 O > hv, chlorophyll> (C 6 H 10 O 5) n + 6nO 2 (obtaining starch or cellulose)

Monosaccharides. All monoses in the crystalline state have a cyclic structure (?- or?-). When dissolved in water, the cyclic hemiacetal is destroyed, turning into a linear (oxo-) form.

The chemical properties of monosaccharides are due to the presence of three types of functional groups in the molecule (carbonyl, alcohol hydroxyls, and glycosidic (hemiacetal) hydroxyl).

1. C 5 H 11 O 5 -CHO (glucose) + Ag 2 O > NH 3 > CH 2 OH- (CHOH) 4 -COOH (gluconic acid) + 2Ag (oxidation)

2. C 5 H 11 O 5 -CHO (glucose) + [H]> CH 2 OH-(CHOH) 4 -CH 2 OH (sorbitol) (reduction)

(monoalkylation)

(polyalkylation)

5. The most important property of monosaccharides is their enzymatic fermentation, i.e., the breakdown of molecules into fragments under the action of various enzymes. Fermentation is mainly carried out by hexoses in the presence of enzymes secreted by yeasts, bacteria or molds. Depending on the nature of the active enzyme, reactions of the following types are distinguished:

a) C 6 H 12 O 6 > 2C 2 H 5 OH + 2CO 2 (alcoholic fermentation);

b) C 6 H 12 O 6 > 2CH 3 -CH (OH) -COOH (lactic acid fermentation);

c) C 6 H 12 O 6 > C 3 H 7 COOH + 2CO 2 + 2H 2 O (butyric fermentation);

d) C 6 H 12 O 6 + O 2 > HOOC-CH 2 -C (OH) (COOH) -CH 2 -COOH + 2H 2 O (citric acid fermentation);

e) 2C 6 H 12 O 6 > C 4 H 9 OH + CH 3 -CO-CH 3 + 5CO 2 + 4H 2 (acetone-butanol fermentation).

Disaccharides. Disaccharides are carbohydrates whose molecules consist of two monosaccharide residues connected to each other by the interaction of hydroxyl groups (two hemiacetal or one hemiacetal and one alcohol). The absence or presence of glycosidic (hemiacetal) hydroxyl affects the properties of disaccharides. Bioses are divided into two groups: regenerating And non-restoring. Reducing bioses are able to exhibit the properties of reducing agents and, when interacting with an ammonia solution of silver, oxidize to the corresponding acids, contain glycosidic hydroxyl in their structure, the relationship between monoses is glycoside-glycose. Education scheme regenerating bios on the example of maltose:

Disaccharides are characterized by a hydrolysis reaction, as a result of which two molecules of monosaccharides are formed:

An example of the most common disaccharides in nature is sucrose (beet or cane sugar). The sucrose molecule consists of β-D-glucopyranose and β-D-fructofuranose residues connected to each other by the interaction of hemiacetal (glycosidic) hydroxyls. Bioses of this type do not show reducing properties, since they do not contain glycosidic hydroxyl in their structure, the relationship between monoses is glycoside-glycosidic. These disaccharides are called non-restoring, i.e. not able to oxidize.

The scheme of formation of sucrose:

Sucrose inversion. Acid hydrolysis of (+) sucrose or the action of invertase produces equal amounts of D (+) glucose and D (-) fructose. Hydrolysis is accompanied by a change in the sign of the specific rotation angle [?] from positive to negative; therefore, the process is called inversion, and the mixture of D(+)glucose and D(-)fructose is called invert sugar.

Polysaccharides (polioses). Polysaccharides are natural high-molecular carbohydrates, the macromolecules of which consist of monosaccharide residues. Main representatives: starch And cellulose, which are built from residues of one monosaccharide - D-glucose. Starch and cellulose have the same molecular formula: (C 6 H 10 O 5) n, but different properties. This is due to the peculiarities of their spatial structure. Starch is made up of ?-D-glucose residues, while cellulose is made up of ?-D-glucose. Starch- a reserve polysaccharide of plants, accumulates in the form of grains in the cells of seeds, bulbs, leaves, stems, is a white amorphous substance insoluble in cold water. Starch - mixture amylose And amylopectin, which are built from residues? -D-glucopyranose.

amylose– linear polysaccharide, the relationship between the residues of D-glucose 1?-4. The chain shape is helical, one turn of the helix contains 6 D-glucose residues. The content of amylose in starch is 15–25%.

Amylopectin– branched polysaccharide, bonds between D-glucose residues – 1?-4 and 1?-6. The content of amylopectin in starch is 75–85%.

1. Formation of ethers and esters (similar to bioses).

2. Qualitative reaction - staining with the addition of iodine: for amylose - in blue, for amylopectin - in red.

3. Acid hydrolysis of starch: starch > dextrins > maltose > α-D-glucose.

Cellulose. Structural polysaccharide of plants, built from residues of β-D-glucopyranose, the nature of the compound is 1β-4. The content of cellulose, for example, in cotton is 90-99%, in hardwoods - 40-50%. This biopolymer has high mechanical strength and acts as a supporting material for plants, forming the walls of plant cells.

1. Acid hydrolysis (saccharification): cellulose > cellobiose > α-D-glucose.

2. Formation of esters

Acetate fibers are made from solutions of cellulose acetate in acetone.

Nitrocellulose is explosive and forms the basis of smokeless powder. Pyroxylin - a mixture of di- and trinitrates of cellulose - is used for the manufacture of celluloid, collodion, photographic films, varnishes.

Organic chemistry - branch of chemistry that studies carbon compounds, their structure, properties , methods of synthesis, as well as the laws of their transformations. Organic compounds are called carbon compounds with other elements (mainly with H, N, O, S, P, Si, Ge, etc.).

The unique ability of carbon atoms to bind to each other, forming chains of various lengths, cyclic structures of various sizes, framework compounds, compounds with many elements, different in composition and structure, determines the diversity of organic compounds. To date, the number of known organic compounds is much more than 10 million and increases every year by 250-300 thousand. The world around us is built mainly from organic compounds, these include: food, clothing, fuel, dyes, medicines, detergents, materials for various branches of technology and the national economy. Organic compounds play a key role in the existence of living organisms.

At the junction of organic chemistry with inorganic chemistry, biochemistry and medicine, the chemistry of organometallic and elemental compounds, bioorganic and medical chemistry, and the chemistry of macromolecular compounds arose.

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

History of the development of organic chemistry

Methods for obtaining various organic substances have been known since antiquity. So, the Egyptians and Romans used dyes of plant origin - indigo and alizarin. Many nations owned the secrets of the production of alcoholic beverages and vinegar from sugar and starch-containing raw materials.

During the Middle Ages, practically nothing was added to this knowledge, some progress began only in the 16-17 centuries (the period of iatrochemistry), when new organic compounds were isolated by distillation of plant products. In 1769-1785 K.V. Scheele isolated several organic acids: malic, tartaric, citric, gallic, lactic and oxalic. In 1773 G.F. Ruel isolated urea from human urine. Substances isolated from animal and 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 Y.Ya. Berzelius, 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 generally accepted that organic chemistry as a science appeared in 1828, when F. Wöhler first 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 indisputable arguments of the inconsistency of the "life force" theory. For example, A. Kolbe synthesized acetic acid, M. Berthelot received methane from H 2 S and CS 2, and A.M. Butlerov synthesized saccharides from formalin.

In the middle of the 19th century the rapid development of synthetic organic chemistry continues, the first industrial production of organic substances is created ( A. Hoffman, W. Perkin Sr.- synthetic dyes, fuchsin, cyanine and aza dyes). Open N.N. Zinin(1842) of the aniline synthesis method served as the basis for the creation of the aniline-dye industry. In the laboratory A. Bayer natural dyes were synthesized - indigo, alizarin, indigo, xanthene and anthraquinone.

An important stage in the development of theoretical organic chemistry was the development F. Kekule theory of valency in 1857, as well as the classical theory of chemical structure A.M. Butlerov in 1861, according to which atoms in molecules are combined in accordance with their valence, the chemical and physical properties of compounds are determined by the nature and number of atoms in them, as well as the type of bonds and the mutual influence of directly unbound atoms. In 1865 F. Kekule proposed the structural formula 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 that for the first time connected the direction of organic reactions with the structure of the substances entering into them. 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 to the vertices of the tetrahedron, in the center of which the carbon atom is located. Based on this model, combined with experimental studies I. Wislicenus(! 873), which showed the identity of the structural formulas of (+)-lactic acid (from sour milk) and (±)-lactic acid, stereochemistry arose - the science of the three-dimensional orientation of atoms in molecules, which predicted in the case of the presence of 4 different substituents at carbon atom (chiral structures) the possibility of the existence of space-mirror isomers (antipodes or enantiomers).

In 1917 Lewis proposed to consider the chemical bond using electron pairs.

In 1931 Hückel applied quantum theory to explain the properties of non-benzenoid aromatic systems, which founded a new direction in organic chemistry - quantum chemistry. This served as an impetus for the further intensive development of quantum chemical methods, in particular the method of molecular orbitals. The stage of penetration of orbital representations into organic chemistry was opened by the theory of resonance L. Pauling(1931-1933) and further work K. Fukui, R. Woodward And R. Hoffmann on the role of frontier orbitals in determining the direction of chemical reactions.

Mid 20th century characterized by a particularly rapid development of organic synthesis. This was determined by the discovery of fundamental processes, such as the production of olefins using ylides ( G. Wittig, 1954), diene synthesis ( O. Diels And C. Alder, 1928), hydroboration of unsaturated compounds ( G. Brown, 1959), nucleotide synthesis and gene synthesis ( A. Todd, H. Qur'an). Advances in the chemistry of organometallic compounds are largely due to the work A.N. Nesmeyanov And G.A. Razuvaeva. In 1951, the synthesis of ferrocene was carried out, the establishment of the "sandwich" structure of which R. Woodward And J. Wilkinson marked the beginning of the chemistry of metallocene compounds and, in general, the organic chemistry of transition metals.

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

In the 60-80s. Ch. Pedersen, D. Cram And J.M. Linen develop the chemistry of crown ethers, cryptands, and other related structures capable of forming strong molecular complexes, and thereby approach the most important problem of "molecular recognition".

Modern organic chemistry continues its rapid development. New reagents, fundamentally new synthetic methods and techniques, new catalysts are introduced into the practice of organic synthesis, previously unknown organic structures are synthesized. The search for organic new biologically active compounds is constantly being conducted. Many more problems of organic chemistry are waiting to be solved, for example, a detailed establishment of the structure-property relationship (including biological activity), the establishment of the structure and stereodirected synthesis of complex natural compounds, the development of new regio- and stereoselective synthetic methods, the search for new universal reagents and catalysts .

The interest of the world community in the development of organic chemistry was vividly demonstrated by the awarding of the Nobel Prize in Chemistry in 2010. R. Heku, A. Suzuki and E. Negishi for his work on the use of palladium catalysts in organic synthesis for the formation of carbon-carbon bonds.

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.

Main 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 bonds;

Unsaturated- contain at least one double (π-bond) and/or triple bond;

open chain(alicyclic);

closed circuit(cyclic) - contain a cycle

These include alkanes, alkenes, alkynes, dienes, cycloalkanes, arenes

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

Alcohol, phenols(contain hydroxyl group OH)

Ethers(contain the grouping R-O-R or R-O-R

Carbonyl compounds(contain the group RR "C = O), these include aldehydes, ketones, quinones.

Compounds containing a carboxyl group(COOH or COOR), these include carboxylic acids, esters

Element- and organometallic compounds

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

Natural compounds - compounds, as a rule, of a rather complex structure, often belonging to several classes of organic compounds at once. Among them are: amino acids, proteins, carbohydrates, alkaloids, terpenes, etc.

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

The structure of organic compounds

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

Very important for understanding the structure of organic compounds is the concept of hybridization of carbon atoms. The carbon atom in the ground state has an electronic configuration 1s 2 2s 2 2p 2, on the basis of which it is impossible to explain the valency 4 inherent in carbon in its compounds and the existence of 4 identical bonds in alkanes directed to the vertices of the tetrahedron. In the framework of the method of valence bonds, this contradiction is resolved by introducing the concept of hybridization. When excited, s→p electron transition and the subsequent, so-called, sp- hybridization, with the energy of the hybridized orbitals being intermediate between the energies s- And p-orbitals. When bonds are formed in alkanes, three R-electron interact with one s-electron ( sp 3 hybridization) and 4 identical orbitals arise, located at tetrahedral angles (109 about 28 ") to each other. Carbon atoms in alkenes are in sp 2-hybrid state: each carbon atom has three identical orbitals lying in the same plane at an angle of 120 about to each other ( sp 2 orbitals), and the fourth ( R-orbital) is perpendicular to this plane. Overlapping R-orbitals of two carbon atoms forms a double (π) bond. The carbon atoms that carry the triple bond are in sp- hybrid state.

Features of organic reactions

Ions are usually involved in inorganic reactions, such reactions proceed quickly and are completed at room temperature. In organic reactions, covalent bonds are often broken with the formation of new ones. As a rule, these processes require special conditions: a certain temperature, reaction time, certain solvents, and often the presence of a catalyst. Usually, not one, but several reactions take place at once. Therefore, when depicting organic reactions, not equations are used, but schemes without calculating stoichiometry. The yields of target substances in organic reactions often do not exceed 50%, and their isolation 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 under vacuum (depending on the boiling point). To control the progress of reactions, separate complex reaction mixtures, various types of chromatography are used [thin-layer chromatography (TLC), preparative high-performance liquid chromatography (HPLC), etc.].

Reactions can proceed very complicatedly and in several stages. Radicals R·, carbocations R + , carbanions R - , carbenes:CX 2 , radical cations, radical anions and other active and unstable particles, usually living for a fraction of a second, can appear as intermediate compounds. A detailed description of all the transformations that occur at the molecular level during a reaction is called reaction mechanism. According to the nature of the gap and the formation of bonds, radical (homolytic) and ionic (heterolytic) processes are distinguished. According to the types of transformations, chain radical reactions, nucleophilic (aliphatic and aromatic) substitution reactions, elimination reactions, electrophilic addition, electrophilic substitution, condensation, cyclization, rearrangement processes, etc. are distinguished. Reactions are also classified according to the methods of their initiation (excitation ), their kinetic order (monomolecular, bimolecular, etc.).

Determination of the structure of organic compounds

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

There are several methods for solving these problems.

• elemental analysis consists in the fact that the substance is decomposed into simpler molecules, by the number of which it is possible to determine the number of atoms that make up the compound. This method does not make it possible to establish the order of bonds between atoms. Often used only to confirm the proposed structure.
• Infrared spectroscopy (IR spectroscopy) and Raman spectroscopy (Raman spectroscopy). The method is based on the fact that 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. The reference data are the number, frequency and intensity of vibrations of the molecule associated with a change in the dipole moment (IC) or polarizability (CR). The method allows you to establish the presence of functional groups, and is also often used to confirm the identity of a substance with some already known substance by comparing their spectra.
• Mass spectrometry. A substance under certain conditions (electron impact, chemical ionization, etc.) turns into ions without loss of atoms (molecular ions) and with loss (fragmentation, fragmentary ions). The method allows you to determine the molecular weight of a substance, its isotopic composition, and sometimes the presence of functional groups. The nature of the fragmentation allows us to draw some conclusions about the structural features and recreate the structure of the compound under study.
• Nuclear magnetic resonance (NMR) method is based on the interaction of nuclei with their own magnetic moment (spin) and placed in an external constant magnetic field (spin reorientation), with variable electromagnetic radiation in the radio frequency range. NMR is one of the most important and informative methods for determining the chemical structure. The method is also used to study the spatial structure and dynamics of molecules. Depending on the nuclei interacting with radiation, there are, for example, the method of proton resonance PMR, NMR 1 H), which allows you to determine the position of hydrogen atoms in a molecule. The 19 F NMR method makes it possible to determine the presence and position of fluorine atoms. The 31 P NMR method provides information on the presence, valence state, and position of phosphorus atoms in a molecule. The 13 C NMR method makes it possible to determine the number and types of carbon atoms; it is used to study 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 12 C isotope has zero spin and cannot be observed by NMR.
• Method of ultraviolet spectroscopy (UV spectroscopy) or electronic transition spectroscopy. 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 energy levels to vacant ones (excitation of the molecule). Most often used to determine the presence and characteristics of conjugate π-systems.
• Methods of analytical chemistry make it possible to determine the presence of certain functional groups by specific chemical (qualitative) reactions, the fact of which can be fixed 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 such as chromatography (thin-layer, gas, liquid) are increasingly used. A place of honor among them is occupied by chromatography-mass spectrometry, which makes it possible not only to assess the degree of purity of the obtained compounds, but also to obtain mass spectral information about the components of complex mixtures.
• Methods for studying the stereochemistry of organic compounds. From the beginning of the 80s. the expediency of developing a new direction in pharmacology and pharmacy associated with the creation of enantiomerically pure drugs with an optimal ratio of therapeutic efficacy and safety has become obvious. Currently, approximately 15% of all synthesized pharmaceuticals are represented by pure enantiomers. This trend was reflected in the appearance in the scientific literature of recent years of the term chiral switch, which in Russian translation means “switching to chiral molecules”. In this regard, methods for establishing the absolute configuration of chiral organic molecules and determining their optical purity are of particular importance in organic chemistry. The main method for determining the absolute configuration should be considered X-ray diffraction analysis (XRD), and optical purity - chromatography on columns with a stationary chiral phase and NMR using special additional chiral reagents.

The connection of organic chemistry with the chemical industry

The main method of organic chemistry - synthesis - closely links organic chemistry with the chemical industry. Based on the methods and developments of synthetic organic chemistry, small-tonnage (fine) organic synthesis arose, including the production of drugs, vitamins, enzymes, pheromones, liquid crystals, organic semiconductors, solar cells, etc. The development of large-tonnage (basic) organic synthesis is also based on the achievements of organic chemistry. The main organic synthesis includes the production of artificial fibers, plastics, processing of oil, gas and coal raw materials.

Recommended reading

• G.V. Bykov, History of organic chemistry, M.: Mir, 1976 (http://gen.lib/rus.ec/get?md5=29a9a3f2bdc78b44ad0bad2d9ab87b87)
• J. March, Organic chemistry: reactions, mechanisms and structure, in 4 volumes, M.: Mir, 1987
• F. Carey, R. Sandberg, Advanced Course in Organic Chemistry, in 2 volumes, M.: Chemistry, 1981
• O.A. Reutov, A.L. Kurtz, K.P. Butin, Organic chemistry, in 4 parts, M .: "Binom, Knowledge Laboratory", 1999-2004. (http://edu.prometey.org./library/author/7883.html)
• Chemical Encyclopedia, ed. Knunyants, M.: "Great Russian Encyclopedia", 1992.