You are starting to study organic chemistry, which you only got a little familiar with in the 9th grade. Why "organic"? Let's turn to history.

Even at the turn of the IX-X centuries. Arab alchemist Abu Bakr ar-Razi (865-925) was the first to divide all chemical substances according to their origin into three kingdoms: mineral, vegetable and animal substances. This unique classification lasted almost a thousand years.

However, at the beginning of the XIX century. there was a need to combine the chemistry of substances of plant and animal origin into a single science. This approach will seem logical to you if you have at least elementary ideas about the composition of living organisms.

From the course of natural science and elementary biology courses, you know that the composition of any living cell, both plant and animal, necessarily includes proteins, fats, carbohydrates and other substances that are commonly called organic. At the suggestion of the Swedish chemist J. Ya. Berzelius, in 1808 the science that studies organic substances began to be called organic chemistry.

The idea of ​​the chemical unity of living organisms on Earth delighted scientists so much that they even created a beautiful but false doctrine - vitalism, according to which it was believed that a special “life force” (vis vitalis) was needed to obtain (synthesis) organic compounds from inorganic ones. Scientists believed that the vital force is a mandatory attribute of only living organisms. From this followed the false conclusion that the synthesis of organic compounds from inorganic outside living organisms - in test tubes or industrial installations - is impossible.

Vitalists reasonably argued that the most important fundamental synthesis on our planet - photosynthesis (Fig. 1) is impossible outside of green plants.

Rice. one.
Photosynthesis

Simplified, the process of photosynthesis is described by the equation

According to the vitalists, any other synthesis of organic compounds outside living organisms is also impossible. However, the further development of chemistry and the accumulation of new scientific facts proved that the vitalists were deeply mistaken.

In 1828, the German chemist F. Wöhler synthesized the organic compound urea from the inorganic substance ammonium cyanate. The French scientist M. Bert-lo in 1854 received fat in a test tube. In 1861, the Russian chemist A. M. Butlerov synthesized a sugary substance. Vitalism has failed.

Now organic chemistry is a rapidly developing branch of chemical science and production. Currently, there are more than 25 million organic compounds, among which there are substances that have not been found in wildlife until today. Obtaining these substances became possible due to the results of the scientific activity of organic chemists.

All organic compounds by origin can be divided into three types: natural, artificial and synthetic.

Natural organic compounds are the waste products of living organisms (bacteria, fungi, plants, animals). These are proteins, fats, carbohydrates, vitamins, hormones, enzymes, natural rubber, etc., well known to you (Fig. 2).

Rice. 2.
Natural organic compounds:
1-4 - in fibers and fabrics (woolen 1, silk 2, linen 3, cotton 4); 5-10 - in food products (milk 5, meat 6, fish 7, vegetable and butter 8, vegetables and fruits 9, cereals and bread 10); 11, 12 - in fuel and raw materials for the chemical industry (natural gas 11, oil 12); 13 - in wood

artificial organic compounds- these are products of chemically converted natural substances into compounds that are not found in wildlife. So, based on the natural organic compound of cellulose, artificial fibers (acetate, viscose, copper-ammonia), non-combustible film and photographic films, plastics (celluloid), smokeless powder, etc. are obtained (Fig. 3).

Rice. 3. Products and materials made on the basis of artificial organic compounds: 1.2 - artificial fibers and fabrics; 3 - plastic (celluloid); 4 - film; 5 - smokeless powder

Synthetic organic compounds obtained synthetically, i.e., by combining simpler molecules into more complex ones. These include, for example, synthetic rubbers, plastics, drugs, synthetic vitamins, growth stimulants, plant protection products, etc. (Fig. 4).

Rice. 4.
Products and materials based on synthetic organic compounds:
1 - plastics; 2 - medicines; 3 - detergents; 4 - synthetic fibers and fabrics; 5 - paints, enamels and glues; 6 - means for combating insects; 7 - fertilizers; 8 - synthetic rubbers

Despite the huge variety, all organic compounds have carbon atoms in their composition. Therefore, organic chemistry can be called the chemistry of carbon compounds.

Along with carbon, most organic compounds contain hydrogen atoms. These two elements form a number of classes of organic compounds, which are called hydrocarbons. All other classes of organic compounds can be considered as derivatives of hydrocarbons. This allowed the German chemist K. Schorlemmer to give a classic definition of organic chemistry, which has not lost its significance even more than 120 years later.

For example, when replacing one hydrogen atom in a C 2 H 6 ethane molecule with a hydroxyl group -OH, the well-known ethyl alcohol C 2 H 5 OH is formed, and when a hydrogen atom in a CH 4 methane molecule is replaced with a carboxyl group -COOH, acetic acid CH is formed 3 COOH.

Why, out of more than a hundred elements of the Periodic system of D. I. Mendeleev, it was carbon that became the basis of all life? Much will become clear to you if you read the following words of D. I. Mendeleev, written by him in the textbook “Fundamentals of Chemistry”: “Carbon is found in nature both in the free and in the connecting state, in very different forms and types ... Ability carbon atoms combine with each other and give complex particles is manifested in all carbon compounds ... In none of the elements ... the ability to complicate is not developed to such an extent as in carbon ... No pair of elements gives so many compounds, like carbon and hydrogen.

The chemical bonds of carbon atoms with each other and with atoms of other elements (hydrogen, oxygen, nitrogen, sulfur, phosphorus), which are part of organic compounds, can be destroyed under the influence of natural factors. Therefore, carbon makes a continuous cycle in nature: from the atmosphere (carbon dioxide) to plants (photosynthesis), from plants to animal organisms, from living to non-living, from non-living to living (Fig. 5).

Rice. 5.
The carbon cycle in nature

In conclusion, we note a number of features that characterize organic compounds.

Since the molecules of all organic compounds contain carbon atoms, and almost all contain hydrogen atoms, most of them are combustible and, as a result of combustion, form carbon monoxide (IV) (carbon dioxide) and water.

Unlike inorganic substances, of which there are about 500 thousand, organic compounds are more diverse, so their number now totals more than 25 million.

Many organic compounds are built more complex than inorganic substances, and many of them have a huge molecular weight, such as proteins, carbohydrates, nucleic acids, i.e., substances due to which life processes occur.

Organic compounds are formed, as a rule, due to covalent bonds and therefore have a molecular structure, and therefore, have low melting and boiling points, and are thermally unstable.

New words and concepts

1. Vitalism.
2. Photosynthesis.
3. Organic compounds: natural, artificial and synthetic.
4. Organic chemistry.
5. Features characterizing organic compounds.

Questions and tasks

1. Using knowledge from a biology course, compare the chemical composition of plant and animal cells. What organic compounds are included in their composition? What is the difference between organic compounds of plant and animal cells?
2. Describe the carbon cycle in nature.
3. Explain why vitalism arose and how it failed.
4. What types of organic compounds (by origin) do you know? Give examples and indicate the areas of their application.
5. Calculate the volume of oxygen (n.a.) and the mass of glucose formed as a result of photosynthesis from 880 tons of carbon dioxide.
6. Calculate the volume of air (n.a.) required to burn 480 kg of methane CH4 if the volume fraction of oxygen in the air is 21%.

All organic compounds, depending on the nature of the carbon skeleton, can be divided into acyclic and cyclic.

Acyclic (non-cyclic, chain) compounds are also called fatty or aliphatic. These names are due to the fact that one of the first well-studied compounds of this type were natural fats. Limiting compounds are distinguished among acyclic compounds, for example:

and unlimited, for example:

Among the cyclic compounds are usually distinguished carbo-cyclic, whose molecules contain rings of carbon atoms, and heterocyclic, whose rings contain, in addition to carbon, atoms of other elements (oxygen, sulfur, nitrogen, etc.).

Carbocyclic compounds are divided into alicyclic (limited and unsaturated), similar in properties to aliphatic, and aromatic, which contain benzene rings.

The considered classification of organic compounds can be represented as a brief scheme

The composition of many organic compounds, in addition to carbon and hydrogen, includes other elements, moreover, in the form of functional groups - groups of atoms that determine the chemical properties of this class of compounds. The presence of these groups makes it possible to subdivide the above types of organic compounds into classes and facilitate their study. Some of the most characteristic functional groups and their corresponding classes of compounds are listed in the table.

functional Group	Name groups	Classes connections
-OH	Hydroxide Carbonyl	Alcohols	C2H5OH Ethanol
		Aldehydes	acetaldehyde
		ketones
	Carboxyl	Carbon acids	acetic acid
—NO 2	Nitro group	Nitro compounds	CH 3 NO 2 Nitrometer
—NH2

All substances that contain a carbon atom, in addition to carbonates, carbides, cyanides, thiocyanates and carbonic acid, are organic compounds. This means that they are able to be created by living organisms from carbon atoms through enzymatic or other reactions. Today, many organic substances can be synthesized artificially, which allows the development of medicine and pharmacology, as well as the creation of high-strength polymer and composite materials.

Classification of organic compounds

Organic compounds are the most numerous class of substances. There are about 20 types of substances here. They are different in chemical properties, differ in physical qualities. Their melting point, mass, volatility and solubility, as well as their state of aggregation under normal conditions, are also different. Among them:

• hydrocarbons (alkanes, alkynes, alkenes, alkadienes, cycloalkanes, aromatic hydrocarbons);
• aldehydes;
• ketones;
• alcohols (dihydric, monohydric, polyhydric);
• ethers;
• esters;
• carboxylic acids;
• amines;
• amino acids;
• carbohydrates;
• fats;
• proteins;
• biopolymers and synthetic polymers.

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

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

These classes of organic compounds can have isomers in different groups of substances. The properties of the isomers are different, although their atomic composition may be the same. This follows from the provisions laid down by A. M. Butlerov. Also, the theory of the structure of organic compounds is the guiding basis for all research in organic chemistry. It is put on the same level with Mendeleev's Periodic Law.

The very concept of chemical structure was introduced by A. M. Butlerov. In the history of chemistry, it appeared on September 19, 1861. Previously, there were different opinions in science, and some scientists completely denied the existence of molecules and atoms. Therefore, there was no order in organic and inorganic chemistry. Moreover, there were no regularities by which it was possible to judge the properties of specific substances. At the same time, there were also compounds that, with the same composition, exhibited different properties.

The statements of A. M. Butlerov in many ways directed the development of chemistry in the right direction and created a solid foundation for it. Through it, it was possible to systematize the accumulated facts, namely, the chemical or physical properties of certain substances, the patterns of their entry into reactions, and so on. Even the prediction of ways to obtain compounds and the presence of some common properties became possible thanks to this theory. And most importantly, A. M. Butlerov showed that the structure of a substance molecule can be explained in terms of electrical interactions.

The logic of the theory of the structure of organic substances

Since before 1861 many in chemistry rejected the existence of an atom or a molecule, the theory of organic compounds became a revolutionary proposal for the scientific world. And since A. M. Butlerov himself proceeds only from materialistic conclusions, he managed to refute the philosophical ideas about organic matter.

He managed to show that the molecular structure can be recognized empirically through chemical reactions. For example, the composition of any carbohydrate can be determined by burning a certain amount of it and counting the resulting water and carbon dioxide. The amount of nitrogen in the amine molecule is also calculated during combustion by measuring the volume of gases and releasing the chemical amount of molecular nitrogen.

If we consider Butlerov's judgments about the chemical structure, which depends on the structure, in the opposite direction, then a new conclusion suggests itself. Namely: knowing the chemical structure and composition of a substance, one can empirically assume its properties. But most importantly, Butlerov explained that in organic matter there is a huge number of substances that exhibit different properties, but have the same composition.

General provisions of the theory

Considering and investigating organic compounds, A. M. Butlerov deduced some of the most important patterns. He combined them into the provisions of the theory explaining the structure of chemicals of organic origin. The provisions of the theory are as follows:

• in the molecules of organic substances, atoms are interconnected in a strictly defined sequence, which depends on valency;
• chemical structure is the direct order according to which atoms are connected in organic molecules;
• the chemical structure determines the presence of the properties of an organic compound;
• depending on the structure of molecules with the same quantitative composition, different properties of the substance may appear;
• 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, A. M. Butlerov was able to expand chemistry as a field of science. He explained that due to the fact that carbon exhibits a valence of four in organic substances, the variety of these compounds is determined. The presence of many active atomic groups determines whether a substance belongs to a certain class. And it is precisely due to the presence of specific atomic groups (radicals) that physical and chemical properties appear.

Hydrocarbons and their derivatives

These organic compounds of carbon and hydrogen are the simplest in composition among all the substances of the group. They are represented by a subclass of alkanes and cycloalkanes (saturated hydrocarbons), alkenes, alkadienes and alkatrienes, alkynes (unsaturated hydrocarbons), as well as a subclass of aromatic substances. In alkanes, all carbon atoms are connected only by a single C-C bond, which is why not a single H atom can be built into the composition of the hydrocarbon.

In unsaturated hydrocarbons, hydrogen can be incorporated at the site of the double C=C bond. Also, the C-C bond can be triple (alkynes). This allows these substances to enter into many reactions associated with the reduction or addition of radicals. All other substances, for the convenience of studying their ability to enter into reactions, are considered as derivatives of one of the classes of hydrocarbons.

Alcohols

Alcohols are called organic chemical compounds more complex than hydrocarbons. They are synthesized as a result 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 the substitution of a halogen atom for a hydroxyl group, alcohols are formed. Monohydric alcohols contain only one hydroxyl group, polyhydric - two or more. An example of a dihydric alcohol is ethylene glycol. The polyhydric alcohol is glycerol. The general formula of alcohols is R-OH (R is a carbon chain).

Aldehydes and ketones

After alcohols enter into reactions of organic compounds associated with the elimination of hydrogen from the alcohol (hydroxyl) group, a double bond between oxygen and carbon closes. If this reaction takes place at the alcohol group located at the terminal carbon atom, then as a result of it, an aldehyde is formed. If the carbon atom with alcohol is not located at the end of the carbon chain, then the result of the dehydration reaction is the production of a ketone. The general formula of ketones is R-CO-R, aldehydes R-COH (R is the hydrocarbon radical of the chain).

Esters (simple and complex)

The chemical structure of organic compounds of this class is complicated. Ethers are considered as reaction products between two alcohol molecules. When water is cleaved from them, a compound of the R-O-R sample is formed. Reaction mechanism: elimination of a hydrogen proton from one alcohol and a hydroxyl group from another alcohol.

Esters are reaction products between an alcohol and an organic carboxylic acid. Reaction mechanism: elimination of water from the alcohol and carbon groups of both molecules. Hydrogen is split off from the acid (along the hydroxyl group), and the OH group itself is separated from the alcohol. The resulting compound is depicted as R-CO-O-R, where the beech R denotes radicals - the rest of the carbon chain.

Carboxylic acids and amines

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

Amines are simpler compounds that are derivatives of hydrocarbons. Here, any carbon atom has an amine radical (-NH2). There are primary amines in which the (-NH2) group is attached to one carbon (general formula R-NH2). In secondary amines, nitrogen combines with two carbon atoms (formula R-NH-R). Tertiary amines have nitrogen attached to three carbon atoms (R3N), where p is a radical, a carbon chain.

Amino acids

Amino acids are complex compounds that exhibit the properties of both amines and acids of organic origin. There are several types of them, depending on the location of the amine group in relation to the carboxyl group. Alpha amino acids are the most important. Here the amine group is located at the carbon atom to which the carboxyl group is attached. This allows you to create a peptide bond and synthesize proteins.

Carbohydrates and fats

Carbohydrates are aldehyde alcohols or keto alcohols. These are compounds with a linear or cyclic structure, as well as polymers (starch, cellulose, and others). Their most important role in the cell is structural and energetic. Fats, or rather lipids, perform the same functions, only they participate in other biochemical processes. Chemically, fat is an ester of organic acids and glycerol.

Classification of organic substances.

Chemistry can be divided into 3 major parts: general, inorganic and organic.

general chemistry considers the regularities relating to all chemical transformations.

Inorganic chemistry studies the properties and transformations of inorganic substances.

Organic chemistry – This is a large and independent branch of chemistry, the subject of which is organic substances:

- their structure;

- properties;

- acquisition methods;

- possibilities of practical use.

Name of organic chemistry suggested Swedish scientist Berzelius.

Before early 19th century All known substances were divided according to their origin into 2 groups:

1) mineral (inorganic) substances and

2) organic substances .

Berzelius and many scientists of those times believed that organic substances could be formed only in living organisms with the help of some kind of "life force". Such idealistic views were called vitalistic (from the Latin "vita" - life). They delayed the development of organic chemistry as a science.

A great blow to the views of the vitalists was dealt by a German chemist V. Wehler . He was the first to obtain organic substances from inorganic:

AT 1824 g. - oxalic acid, and

AT 1828 g. - urea.

In nature, oxalic acid is found in plants, and urea is formed in humans and animals.

There were more and more such facts.

AT 1845 German scientist Kolbe synthesized acetic acid from charcoal.

AT 1854 Mr. French scientist M. Berthelot synthesized a fat-like substance.

It became clear that no "life force" existed, that the substances isolated from the organisms of animals and plants could be synthesized artificially, that they were of the same nature as all other substances.

Nowadays organic matter consider carbonaceous substances that are formed in nature (living organisms) and can be obtained synthetically. That is why organic chemistry is called chemistry of carbon compounds.

Features of organic substances .

Unlike inorganic substances, organic substances have a number of features that are due to the structural features of the carbon atom.

Features of the structure of the carbon atom.

1) In the molecules of organic substances, the carbon atom is in an excited state and exhibits a valence equal to IV.

2) When molecules of organic substances are formed, the electron orbitals of the carbon atom can undergo hybridization ( hybridization – it is the alignment of electron clouds in form and energy).

3) Carbon atoms in the molecules of organic substances are able to interact with each other, forming chains and rings.

Classification of organic compounds.

There are various classifications of organic substances:

1) by origin,

2) by elemental composition,

3) according to the type of carbon skeleton,

4) by the type of chemical bonds,

5) according to the qualitative composition of functional groups.

Classification of organic substances by origin.

Classification of organic substances by elemental composition.

organic matter
hydrocarbons	oxygen-containing	In addition to carbon, hydrogen and oxygen contain nitrogen and other atoms.
Consist of carbon and hydrogen	Consist of carbon, hydrogen and oxygen
Limit HC
Unlimited HC		Amino acids
Aromatic HC	Aldehydes
	carboxylic acids	Nitro compounds
	Esters (simple and complex)
	Carbohydrates

Classification of organic substances according to the type of carbon skeleton.

Carbon skeleton -it is a sequence of chemically bonded carbon atoms.

Classification of organic substances according to the type of chemical bonds.

Classification of organic substances according to the qualitative composition of functional groups.

Functional group – a permanent group of atoms that determines the characteristic properties of a substance.

Functional group	Name	Organic class	Suffixes and prefixes
-F, -Cl, -Br, -J	Fluorine, chlorine, bromine, iodine (halogen)	halogen derivatives	fluoromethane chloromethane bromomethane iodomethane
	hydroxyl	Alcohols, phenols
- C \u003d O	carbonyl	Aldehydes, ketones	- al methanal
- COOH	carboxyl	carboxylic acids	methane acid
- NO2	nitro group	Nitro compounds	Nitro nitromethane
- NH2	amino group		- amine methylamine

Lesson 3-4

Topic: Basic provisions of the theory of the structure of organic compounds

.

Reasons for the diversity of organic substances (homology, isomerism ).

By the start of the second half 19th century quite a lot of organic compounds were known, but there was no unified theory explaining their properties. Attempts to create such a theory have been made repeatedly. None were successful.

We owe the creation of a theory of the structure of organic substances .

In 1861, at the 36th Congress of German naturalists and doctors in Speyer, Butlerov made a report in which he outlined the main provisions of a new theory - the theory of the chemical structure of organic substances.

The theory of the chemical structure of organic substances did not arise from scratch.

The objective prerequisites for its appearance were :

1) socio-economic background .

The rapid development of industry and trade since the beginning of the 19th century placed high demands on many branches of science, including organic chemistry.

They put before this science new tasks:

- obtaining dyes synthetically,

- improvement of methods for processing agricultural products and etc.

2) Scientific background .

There were many facts that required explanation:

- Scientists could not explain the valency of carbon in compounds such as ethane, propane, etc.

- Scientists chemists could not explain why two elements: carbon and hydrogen can form such a large number of different compounds and why org. there are so many substances.

- It was not clear why organic substances with the same molecular formula (C6H12O6 - glucose and fructose) can exist.

A scientifically substantiated answer to these questions was given by the theory of the chemical structure of organic substances.

By the time the theory appeared, much was already known :

- A. Kekule proposed quadrivalent carbon atom for organic compounds.

- A. Cooper and A. Kekule suggested about carbon-carbon bonds and the possibility of connecting carbon atoms in the chain.

AT 1860 . at the International Congress of Chemists clearly defined concepts of atom, molecule, atomic weight, molecular weight .

The essence of the theory of the chemical structure of organic substances can be expressed as follows :

1. All atoms in the molecules of organic substances are interconnected in a certain order by chemical bonds according to their valency.

2. The properties of substances depend not only on which atoms and how many of them are part of the molecule, but also on the order of connection of atoms in the molecule .

The order of connection of atoms in a molecule and the nature of their bonds Butlerov called chemical structure .

The chemical structure of a molecule is expressed structural formula , in which the symbols of the elements of the corresponding atoms are connected by dashes ( valence strokes) which denote covalent bonds.

Structural formula conveys :

The sequence of connection of atoms;

The multiplicity of bonds between them (simple, double, triple).

Isomerism - it is the existence of substances having the same molecular formula but different properties.

Isomers - these are substances that have the same composition of molecules (one and the same molecular formula), but a different chemical structure and therefore have different properties.

3. By the properties of a given substance, one can determine the structure of its molecule, and by the structure of a molecule one can predict properties.

The properties of substances depend on the type of crystal lattice.

4. Atoms and groups of atoms in the molecules of substances mutually influence each other.

The value of the theory.

The theory created by Butlerov was first greeted negatively by the scientific world, because its ideas contradicted the idealistic worldview prevailing at that time, but after a few years the theory became generally recognized, this was facilitated by the following circumstances:

1. The theory has put things in order the unimaginable chaos in which organic chemistry was before it. The theory made it possible to explain new facts, proved that with the help of chemical methods (synthesis, decomposition, and other reactions) it is possible to establish the order of connection of atoms in molecules.

2. Theory has introduced something new into the atomic and molecular theory

The arrangement of atoms in molecules,

Mutual influence of atoms

Dependence of properties on a substance molecule.

3. The theory was able not only to explain the already known facts, but also made it possible to foresee the properties of organic substances on the basis of the structure to synthesize new substances.

4. Theory made it possible to explain manifold chemical substances.

5. She gave a powerful impetus to the synthesis of organic substances.

The development of the theory proceeded, as Butlerov had foreseen, mainly in two directions. :

1. Study of the spatial structure of molecules (the actual arrangement of atoms in three-dimensional space)

2. Development of electronic representations (revealing the essence of the chemical bond).

There are many organic compounds, but among them there are compounds with common and similar properties. Therefore, they are all classified according to common characteristics, combined into separate classes and groups. The classification is based on hydrocarbons – compounds that are made up of only carbon and hydrogen atoms. The rest of the organic matter is "Other Classes of Organic Compounds".

Hydrocarbons are divided into two broad classes: acyclic and cyclic compounds.

Acyclic compounds (fatty or aliphatic) – compounds whose molecules contain an open (not closed in a ring) unbranched or branched carbon chain with single or multiple bonds. Acyclic compounds are divided into two main groups:

saturated (limiting) hydrocarbons (alkanes), in which all carbon atoms are interconnected only by simple bonds;

unsaturated (unsaturated) hydrocarbons, in which between carbon atoms, in addition to single simple bonds, there are also double and triple bonds.

Unsaturated (unsaturated) hydrocarbons are divided into three groups: alkenes, alkynes and alkadienes.

Alkenes(olefins, ethylene hydrocarbons) – acyclic unsaturated hydrocarbons that contain one double bond between carbon atoms form a homologous series with the general formula C n H 2n . The names of alkenes are formed from the names of the corresponding alkanes with the suffix "-an" replaced by the suffix "-en". For example, propene, butene, isobutylene or methylpropene.

Alkynes(acetylene hydrocarbons) – hydrocarbons that contain a triple bond between carbon atoms form a homologous series with the general formula C n H 2n-2 . The names of alkenes are formed from the names of the corresponding alkanes with the suffix "-an" replaced by the suffix "-in". For example, ethin (acylene), butin, peptin.

Alkadienes – organic compounds that contain two carbon-carbon double bonds. Depending on how the double bonds are arranged relative to each other, dienes are divided into three groups: conjugated dienes, allenes and dienes with isolated double bonds. Typically, dienes include acyclic and cyclic 1,3-dienes, forming with the general formulas C n H 2n-2 and C n H 2n-4 . Acyclic dienes are structural isomers of alkynes.

Cyclic compounds, in turn, are divided into two large groups:

1. carbocyclic compounds – compounds whose rings consist only of carbon atoms; Carbocyclic compounds are subdivided into alicyclic – saturated (cycloparaffins) and aromatic;
2. heterocyclic compounds – compounds whose cycles consist not only of carbon atoms, but of atoms of other elements: nitrogen, oxygen, sulfur, etc.

In molecules of both acyclic and cyclic compounds hydrogen atoms can be replaced by other atoms or groups of atoms, thus, by introducing functional groups, derivatives of hydrocarbons can be obtained. This property further expands the possibilities of obtaining various organic compounds and explains their diversity.

The presence of certain groups in the molecules of organic compounds determines the generality of their properties. This is the basis for the classification of derivatives of hydrocarbons.

"Other classes of organic compounds" include the following:

Alcohols are obtained by replacing one or more hydrogen atoms with hydroxyl groups – Oh. It is a compound with the general formula R – (OH) x, where x – number of hydroxyl groups.

Aldehydes contain an aldehyde group (C = O), which is always at the end of the hydrocarbon chain.

carboxylic acids contain one or more carboxyl groups – COOH.

Esters – derivatives of oxygen-containing acids, which are formally the products of substitution of hydrogen atoms of hydroxides – OH acid function per hydrocarbon residue; are also considered as acyl derivatives of alcohols.

Fats (triglycerides) – natural organic compounds, full esters of glycerol and monocomponent fatty acids; belong to the class of lipids. Natural fats contain three linear acid radicals and usually an even number of carbon atoms.

Carbohydrates – organic substances containing a straight chain of several carbon atoms, a carboxyl group and several hydroxyl groups.

Amines contain an amino group – NH2

Amino acids– organic compounds, the molecule of which simultaneously contains carboxyl and amine groups.

Squirrels – high-molecular organic substances, which consist of alpha-amino acids connected in a chain by a peptide bond.

Nucleic acids – high-molecular organic compounds, biopolymers formed by nucleotide residues.

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