Formulas of organic compounds and their names. Theory of the chemical structure of organic compounds. Classification of organic substances

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 valence;
  • 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.

The classification of organic compounds is based on the theory of the chemical structure of A. M. Butlerov. Systematic classification is the foundation of scientific nomenclature. Thanks to it, it became possible to give a name to each previously known and new organic substance, based on the existing

Classes of organic compounds

They are classified according to two main features: localization and the number of functional groups in the molecule and the structure of the carbon skeleton.

The carbon skeleton is a part of a molecule that is quite stable in various chemical reactions. Organic compounds are divided into large groups, while taking into account organic matter.

Acyclic compounds(bio-fatty compounds or aliphatic compounds). These organic compounds in the structure of the molecules contain a straight or branched carbon chain.

Carbocyclic compounds are substances with closed carbon chains - cycles. These biocompounds are divided into groups: aromatic and alicyclic.

Heterocyclic natural organic compounds- substances in the structure of molecules of which there are cycles formed by atoms of carbon and atoms of other chemical elements (Oxygen, Nitrogen, Sulfur) heteroatoms.

The compounds of each series (group) are divided into classes of various organic compounds. The belonging of an organic substance to a particular class is determined by the presence of certain functional groups in its molecule. For example, the classes of hydrocarbons (the only class of organic substances that lack functional groups), amines, aldehydes, phenols, carboxylic acids, ketones, alcohols, etc.

To determine whether an organic compound belongs to a series and class, a carbon skeleton or a carbon chain (acyclic compounds), a cycle (carbocyclic compounds) or a core is isolated. Further, the presence of other atomic (functional) groups in the molecule of the organic substance, for example, hydroxyl - OH, carboxyl - COOH, amino group, imino group, sulfhydride group - SH, etc. The functional group or groups determine whether a biocompound belongs to a certain class, its main physical and chemical properties. It should be said that each functional group not only determines these properties, but also affects other atoms and atomic groups, simultaneously experiencing their influence.

When acyclic and cyclic hydrocarbons or heterocyclic compounds of the hydrogen atom are replaced by various functional groups in molecules, organic compounds are obtained that belong to certain classes. Here are separate functional groups that determine whether an organic compound belongs to a certain class: hydrocarbons R-H, halogen derivatives of hydrocarbons - R-Hal, aldehydes - R-COH, ketones - R1-CO-R2, alcohols and phenols R-OH, carboxylic acids - R-COOH , - R1-O-R2, carboxylic acid halides R-COHal, R-COOR, nitro compounds - R-NO2, sulfonic acids -R-SO3H, organometallic compounds - R-Me, mercaptans R-SH.

Organic compounds that have one functional group in the structure of their molecules are called organic compounds with simple functions, two or more - compounds with mixed functions. Examples of organic compounds with simple functions are hydrocarbons, alcohols, ketones, aldehydes, amines, carboxylic acids, nitro compounds, etc. Examples of compounds with mixed functions can be hydroxy acids, keto acids, and the like.

A special place is occupied by complex bioorganic compounds: proteins, proteids, lipids, nucleic acids, carbohydrates, in the molecules of which there are a large number of different functional groups.

Purpose of the lecture: familiarity with the classification and nomenclature of organic compounds

Plan:

1. Subject and tasks of organic chemistry. Its significance for pharmacy.

2. Classification of organic compounds.

3. Principles of trivial and rational nomenclature.

4. Principles of IUPAC nomenclature.

Subject and tasks of organic chemistry.

Organic chemistry is a branch of chemistry devoted to the study of the structure, methods of synthesis and chemical transformations of hydrocarbons and their functional derivatives.

The term "organic chemistry" was first introduced by the Swedish chemist Jens Jakob Berzellius in 1807.

Due to the peculiarities of their structure, organic substances are very numerous. Today their number reaches 10 million.

At present, the state of organic chemistry is such that it makes it possible to scientifically plan and carry out the synthesis of any complex molecules (proteins, vitamins, enzymes, drugs, etc.).

Organic chemistry is closely related to pharmacy. It allows the isolation of individual medicinal substances from plant and animal raw materials, synthesizes and purifies medicinal raw materials, determines the structure of the substance and the mechanism of chemical action, and allows determining the authenticity of a particular drug. Suffice it to say that 95% of medicines are organic in nature.

Classification of organic compounds

In the classification, two most important features are taken as a basis: structure carbon skeleton and the presence in the molecule functional groups.

According to the structure of the carbon skeleton, organic. compounds are divided into three large groups.

I Acyclic(aliphatic) compounds having an open carbon chain, both straight and branched.

The parent compounds in organic chemistry are recognized hydrocarbons consisting only of carbon and hydrogen atoms. A variety of organic compounds can be considered as derivatives of hydrocarbons obtained by introducing functional groups into them.


A functional group is a structural fragment of a molecule that is characteristic of a given class of organic compounds and determines its chemical properties.

For example, the properties of alcohols are determined by the presence of a hydroxo group ( - IS HE), properties of amines - amino groups ( - NH2), carboxylic acids by the presence of a carboxyl group in the molecule (- UNSD) etc.

Table 1. Main classes of organic compounds

This classification is important because the functional groups largely determine the chemical properties of this class of compounds.

If the compounds contain several functional groups and they are the same, then such compounds are called polyfunctional (CH 2 IS HE- CH IS HE- CH 2 IS HE- glycerol), if the molecule contains different functional groups, then this heterofunctional compound (CH 3 - CH ( IS HE)- UNSD- lactic acid). Heterofunctional compounds can be immediately attributed to several classes of compounds.

In the transition from inorganic to organic chemistry, one can trace how the classification of organic and inorganic substances differs. The world of organic compounds has a variety and multiplicity of their options. The classification of organic substances not only helps to understand this abundance, but also provides a clear scientific basis for their study.

The theory of chemical structure was chosen as the basis for the distribution by class. The basis of the study of organics is the work with the most numerous class, which is usually called the main one for organic substances - hydrocarbons. Other representatives of the organic world are considered as their derivatives. Indeed, when studying their structure, it is not difficult to notice that the synthesis of these substances occurs by replacing (substituting) one, and sometimes several hydrogen units in the hydrocarbon structure with atoms of other chemical elements, and sometimes with entire radical branches.

The classification of organic substances was based on hydrocarbons also because of the simplicity of their composition, and the hydrocarbon component is the most significant part of most known organic compounds. To date, of all known organics related to the world, compounds built on the basis have a significant predominance. All other substances are either in the minority, allowing them to be classified as an exception to the general rule, or are so unstable that it is difficult to obtain them even in our time.

The classification of organic substances by dividing into separate groups and classes allows us to distinguish two large organic classes of acyclic and cyclic compounds. Their very name allows us to draw a conclusion about the type of construction of the molecule. In the first case, this is a chain of hydrocarbon units, and in the second, the molecule is a ring.

Acyclic compounds may be branched or may form a simple chain. Among the names of these substances can be found the expression "fatty or aliphatic hydrocarbons." They can be limiting (ethane, isobutane, or unsaturated (ethylene, acetylene, isoprene), depending on the type of bond of some carbon units.

The classification of organic substances related to cyclic compounds implies their further division into a group of carbocyclic and a group of heterocyclic hydrocarbons.

Carbocyclic "rings" are made up of only carbon atoms. They can be alicyclic (saturated and unsaturated) and also be aromatic carbocyclic compounds. In alicyclic compounds, the two ends of the carbon chain are simply connected, but aromatic compounds have the so-called benzene ring in their structure, which has a significant effect on their properties.

In heterocyclic substances, atoms of other substances can be found, most often this function is performed by nitrogen.

The next constituent element that affects the properties of organic substances is the presence of a functional group.

For halogen derivatives of hydrocarbons, one or even several halogen atoms can act as a functional group. Alcohols get their properties due to the presence of hydroxo groups. For aldehydes, a characteristic feature is the presence of aldehyde groups, for ketones - carbonyl groups. Carboxylic acids differ in that they contain carboxyl groups, and amines have an amino group. Nitro compounds are characterized by the presence of a nitro group.

The variety of types of hydrocarbons, as well as their properties, is based on the most diverse type of combination. For example, the composition of one molecule may include two or more identical, and sometimes different functional groups, determining the specific properties of this substance (glycerin).

A table that can be easily compiled on the basis of the information presented in the text of this article will provide greater clarity for considering the issue (classification of organic substances).

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 valence;
  • 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.

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