Is it possible, without risking a mistake, to name such an area of the world around us in which it would be impossible to detect organic substances? It is very difficult to do this: organic substances are everywhere - in the water of rivers and seas, in the sands of a waterless desert, in the bowels of the earth, in the air and, probably, even in infinite space, for example, in the form of the simplest hydrocarbons. But when we think about the significance of organic compounds, it is not so much the breadth of their distribution that is striking, but the diversity and those truly inexhaustible possibilities that nature and man have to obtain new substances.
What underlies this diversity? First of all, the ability of carbon atoms to bind with each other and with atoms of other elements, such as oxygen, sulfur, nitrogen, phosphorus, in chains of various lengths that form the "skeleton" of molecules - cyclic and non-cyclic. Another reason lies in the phenomenon of isomerism. A change in the sequence of connecting atoms in molecules consisting only of carbon and hydrogen leads to new substances, the number of which grows very rapidly with an increase in the number of atoms.
Of course, man has been able to discover in nature or to synthesize in the laboratory only a tiny fraction of such isomeric hydrocarbons. It is understandable. Already the number of isomers corresponding to the composition C 25 H 52 is ten times greater than the number of currently studied organic substances. But organic chemistry as a science has existed for more than 100 years. The possibilities for isomerism, as is easy to understand, increase with the complication of the composition of the molecule, for example, when other elements are introduced into the hydrocarbon molecule. For example, when only one hydrogen atom is replaced by chlorine in a hydrocarbon molecule, the possibility of isomerism appears already in the case of a propane derivative:
CH 3 -CH 2 -CH 2 Cl and CH 3 -CHCl-CH 3 . For dichloro derivatives of hydrocarbons, isomers exist, starting already with dichloroethane: CH 2 Cl-CH 2 Cl and CH 3 -CHCl 2.
Does the possibility of the existence of isomers, differing in the order of atomic linkage, exhaust the whole variety, the whole world of organic substances? We will be able to answer this question by referring to the history of the emergence of spatial representations in the framework of the theory of the chemical structure of organic compounds.
1. Theory of A. M. Butlerov
The first public speech by A. M. Butlerov on theoretical issues of organic chemistry dates back to the end of the 50s: this is his report at a meeting of the Paris Chemical Society on February 17, 1858. It says that not only organic groups should be considered as radicals, but also groups like OH, NH 2, that is, combinations of atoms characteristic of various classes of organic substances, which later became known as functional groups. In the same report, A. M. Butlerov for the first time used the term “structure” itself, referring to the homogeneous type of molecular structure methane, methyl chloride, methylene chloride, chloroform, carbon tetrachloride, methyl alcohol.
In a more developed form, the idea of \u200b\u200bthe chemical structure was presented by A. M. Butlerov three years later in the report "On the Chemical Structure of Substances", with which he spoke at the congress of natural scientists in Speyer. In this report, first of all, it was said that the theoretical side of chemistry does not correspond to the actual development, in particular, the insufficiency of the theory of types was noted. At the same time, A. M. Butlerov was far from indiscriminately denying it; he rightly pointed out that the theory of types also had important merits: thanks to it, the concepts of atom, particle (molecule), equivalent, equivalent and molecular weights entered science; Thanks to this theory, chemists have learned to put facts first everywhere.
In this report, he also gave his clear definition of the chemical structure: “I call the chemical structure the distribution of the action of this force (affinity), due to which chemical atoms, indirectly or directly influencing each other, combine into a chemical particle.” Speaking about the chemical structure, A. M. Butlerov considered it necessary to clearly explain what he means by the “chemical interaction of atoms”, leaving the question open for the time being, whether atoms are adjacent to each other, chemically directly acting on each other. The subsequent development of science showed that there is a correspondence between the chemical structure and spatial arrangement, but at the time of A. M. Butlerov, science did not yet provide material for resolving this issue.
Using the concept of chemical structure, A. M. Butlerov gave in his report the well-known classical formulation: “The chemical nature of a complex particle is determined by the nature of elementary constituents, their number and chemical structure.” The report goes on to talk about ways that can be used to study the chemical structure. The latter can be judged primarily on the basis of the methods of synthesis of a substance, and the most reliable conclusions can be made by studying syntheses "which take place at a slightly elevated temperature, and in general under conditions where one can follow the course of the gradual complication of a chemical particle." Decomposition reactions - mostly also proceeding under mild conditions - also make it possible to draw conclusions about the chemical structure, that is, to believe that "residues (radicals) were ready in the decomposed particle." At the same time, A. M. Butlerov foresaw that not all reactions are suitable for determining the structure: among them there are those in which "the chemical role of some shares changes, and hence the structure." Translated into our modern language, these are reactions accompanied by isomerization of the skeleton or transfer of the reaction center.
The rational formula built on the basis of the chemical structure, emphasized A. M. Butlerov, will be unambiguous: “For each body, only one rational formula will be possible, and when the general laws of the dependence of the chemical properties of bodies on the chemical structure become known, then a similar the formula will be an expression of all these properties. Typical formulas in their present meaning should then go out of use ... The fact is that these formulas are too narrow for the present state of science!
2. Discovery of the phenomenon of isomerism
This theory, the main provisions of which were formulated by A. M. Butlerov in 1861, considered the structure of organic compounds, primarily as a sequence of bonds of atoms in a molecule. The question of the arrangement of atoms in space at that time had not yet been discussed. It wasn't an accident. Until the beginning of the 20th century, science did not yet have physical methods to prove the real existence of atoms, and even more so their spatial arrangement. However, since the 70s of the 19th century, chemistry developed ideas about the spatial arrangement of atoms in molecules, which were brilliantly confirmed by physical studies much later.
The appearance of spatial representations in organic chemistry was due to the fact that the theory of structure in its original form could not explain some cases of isometry. We are talking about optical isomers - compounds whose structure was expressed by the same formula, and all the chemical properties of such compounds completely coincided. They did not differ in physical properties, except for one thing - the ability to rotate the plane of polarized light in one direction or another. Ordinary light, as you know, can be imagined as waves oscillating in various planes perpendicular to the direction of the beam. Some minerals, such as Icelandic spar (a transparent variety of calcium carbonate CaCO 3 ), have the ability to transmit light vibrations that are only in a certain plane. Light passing through such a crystal or a specially prepared prism (polarizer) is called plane polarized. As was established at the beginning of the 19th century, many crystals, such as quartz, as well as some organic substances in a liquid state or in solutions, are capable of rotating the plane of polarized light. This phenomenon is often referred to as optical activity or optical rotation. It is easy to detect by placing in the path of the light that has passed through the polarizer and the solution of the substance under study, a second analyzer prism, which, like the polarizer, transmits vibrations lying in the same plane. In this case, the angle by which the analyzer must be rotated in order to obtain the same light intensity as when passing through a solvent in the absence of an optically active substance is equal to the angle of optical rotation. The most striking example of an optically active organic compound is tartaric acid, studied in the middle of the last century by L. Pasteur. Natural tartaric acid rotates the plane of polarization to the right and is designated as d-tartaric acid (from the Latin dextro - right). With prolonged heating d-tartaric acid loses its optical activity, turning into a mixture of dextrorotatory and levorotatory acids. From this mixture, L. Pasteur managed to isolate the levorotatory l- tartaric acid (from the Latin laevo - left). Both acids have the same structural formula.
The subject and role of organic chemistry. Theory of the chemical structure of organic compounds A.M. Butlerov and its significance.
Organic chemistry, a science that studies the compounds of carbon with other elements (organic compounds), as well as the laws of their transformations.
The diversity and huge number of organic compounds determines the importance of organic chemistry as the largest branch of modern chemistry. The world around us is built mainly from organic compounds; food, fuel, clothing, medicines, paints, detergents, explosives, materials without which it is impossible to create transport, printing, penetration into space, and so on - all this consists of organic compounds. Organic compounds play an important role in life processes. Organic chemistry studies not only compounds obtained from plant and animal organisms (the so-called natural substances), but mainly compounds created artificially using laboratory or industrial organic synthesis.
The main provisions of the theory of chemical structure of A.M. Butlerov
1. Atoms in molecules are connected to each other in a certain sequence according to their valencies. The sequence of interatomic bonds in a molecule is called its chemical structure and is reflected by one structural formula (structural formula).
2. The chemical structure can be established by chemical methods. (Currently modern physical methods are also used).
3. The properties of substances depend on their chemical structure.
4. By the properties of a given substance, you can determine the structure of its molecule, and by the structure of the molecule, you can predict the properties.
5. Atoms and groups of atoms in a molecule mutually influence each other.
Butlerov's theory was the scientific foundation of organic chemistry and contributed to its rapid development. Based on the provisions of the theory, A.M. Butlerov gave an explanation for the phenomenon of isomerism, predicted the existence of various isomers, and obtained some of them for the first time.
The phenomenon of isomerism of organic compounds, its types.
At the heart of isomerism, as shown by A.M. Butlerov, lies the difference in the structure of molecules consisting of the same set of atoms. Thus, isomerism- this is the phenomenon of the existence of compounds that have the same qualitative and quantitative composition, but a different structure and, consequently, different properties.
For example, when a molecule contains 4 carbon atoms and 10 hydrogen atoms, the existence of 2 isomeric compounds is possible:
Depending on the nature of the differences in the structure of isomers, structural and spatial isomerism are distinguished.
Structural isomers- compounds of the same qualitative and quantitative composition, differing in the order of binding atoms, i.e. chemical structure.
For example, the composition C 5 H 12 corresponds to 3 structural isomers:
Spatial isomers (stereoisomers) with the same composition and the same chemical structure, they differ in the spatial arrangement of atoms in the molecule.
Spatial isomers are optical and cis-trans isomers. The molecules of such isomers are spatially incompatible. 
Electronic representations in organic chemistry. The structure of the carbon atom. Hybridization of orbitals (valence states of the carbon atom). Covalent bond and its types (simple, or δ- and multiple).
The application of the electronic theory of the structure of the atom and chemical bonding in organic chemistry was one of the most important stages in the development of the theory of the structure of organic compounds. The concept of chemical structure as a sequence of bonds between atoms (A.M. Butlerov) was supplemented by electronic theory with ideas about the electronic and spatial structure and their influence on the properties of organic compounds. It is these representations that make it possible to understand the ways of transferring the mutual influence of atoms in molecules (electronic and spatial effects) and the behavior of molecules in chemical reactions.
According to modern ideas, the properties of organic compounds are determined by:
the nature and electronic structure of atoms;
the type of atomic orbitals and the nature of their interaction;
the type of chemical bonds;
· chemical, electronic and spatial structure of molecules.
The carbon atom is made up from a nucleus that has a positive charge of +6 (because it contains six protons), and an electron shell, on which there are six electrons located at two energy levels (layers). Electronic configuration in ground state 1s 2 2s 2 2p 2 .
In the normal (unexcited) state, the carbon atom has two unpaired 2 R 2 electrons. In an excited state (when energy is absorbed) one of 2 s 2-electrons can pass to free R-orbital. Then four unpaired electrons appear in the carbon atom:
hybridization orbitals is called the process of aligning them in shape and energy. The number of hybrid orbitals is equal to the number of original orbitals. Compared to them, hybrid orbitals are more elongated in space, which ensures their more complete overlap with the orbitals of neighboring atoms.
sp- Hybridization
is a mixing (alignment in form and energy) of one s- and one R-orbitals with the formation of two hybrid sp-orbitals. sp- Orbitals are located on the same line (at an angle of 180 °) and directed in opposite directions from the nucleus of the carbon atom. Two R-orbitals remain unhybridized. They are located mutually perpendicular to the directions of -bonds. 
There are three types of covalent chemical bonds that differ in the mechanism of formation:
1. Simple covalent bond. For its formation, each of the atoms provides one unpaired electron. When a simple covalent bond is formed, the formal charges of the atoms remain unchanged.
If the atoms forming a simple covalent bond, are the same, then the true charges of the atoms in the molecule are also the same, since the atoms that form the bond equally own a socialized electron pair, such a bond is called non-polar covalent bond.
If the atoms different, then the degree of ownership of a socialized pair of electrons is determined by the difference in the electronegativity of atoms. An atom with greater electronegativity attracts a pair of bond electrons to itself more strongly, and its true charge becomes negative. An atom with less electronegativity acquires the same positive charge. This covalent bond is called polar.
2. Donor-acceptor bond. To form this type of covalent bond, both electrons provide one of the atoms - a donor. The second of the atoms involved in the formation of a bond is called an acceptor. In the resulting molecule, the formal charge of the donor increases by one, while the formal charge of the acceptor decreases by one.
3. Semipolar connection. This type of covalent bond is formed between an atom that has an unshared pair of electrons (nitrogen, phosphorus, sulfur, halogens, etc.) and an atom with two unpaired electrons (oxygen, sulfur). The formation of a semipolar bond proceeds in two stages:
· Oxidation (transfer of one electron);
Socialization of unpaired electrons.
σ bond (sigma bond)- a covalent bond formed by the overlapping of electron clouds "along the center line". Characterized by axial symmetry. A bond formed when hybrid orbitals overlap along a line connecting the nuclei of an atom.
Classification of organic compounds. Functional groups and the most important classes of organic compounds. heterofunctional compounds. Qualitative functional analysis (chemical identification of classes of organic 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 (alkenes, alkynes and alkadienes), in which between carbon atoms, in addition to single simple bonds, there are also double and triple bonds.
Cyclic compounds, in turn, are divided into two large groups:
- carbocyclic compounds - compounds whose rings consist only of carbon atoms; Carbocyclic compounds are classified into alicyclic - saturated (cycloparaffins) and aromatic;
- heterocyclic compounds - compounds whose cycles consist not only of carbon atoms, but of atoms of other elements: nitrogen, oxygen, sulfur, etc.
"Other classes of organic compounds" include the following: alcohols, aldehydes, carboxylic acids, esters, fats, carbohydrates, amines, amino acids, proteins, nucleic acids.
Most of the organic substances involved in metabolic processes are heterofunctional compounds, i.e. having several different functional groups in its structure. The most common heterofunctional compounds are amino alcohols, amino acids, hydroxy acids and oxo acids. The chemical properties of heterofunctional compounds cannot be considered as the sum of properties due to the presence of each functional group. Since functional groups influence each other, heterofunctional compounds also have specific chemical properties.
Qualitative Analysis aims to detect certain substances or their components in the analyzed object. Detection is carried out by identification substances, that is, establishing the identity (sameness) of the AS of the analyzed object and the known AS of the determined substances under the conditions of the applied method of analysis. To do this, this method preliminarily examines reference substances in which the presence of the substances to be determined is known.
>> Chemistry: Isomerism and its types
There are two types of isomerism: structural and spatial (stereoisomerism). Structural isomers differ from each other in the order of bonds of atoms in a molecule, stereo-isomers - in the arrangement of atoms in space with the same order of bonds between them.
The following types of structural isomerism are distinguished: carbon skeleton isomerism, position isomerism, isomerism of various classes of organic compounds (interclass isomerism).
Structural isomerism
The isomerism of the carbon skeleton is due to the different bond order between the carbon atoms that form the skeleton of the molecule. As already shown, the molecular formula C4H10 corresponds to two hydrocarbons: n-butane and isobutane. Three isomers are possible for the C5H12 hydrocarbon: pentane, iso-pentane, and neopentane.
With an increase in the number of carbon atoms in a molecule, the number of isomers increases rapidly. For the hydrocarbon С10Н22 there are already 75 of them, and for the hydrocarbon С20Н44 - 366 319.
Position isomerism is due to the different position of the multiple bond, substituent, functional group with the same carbon skeleton of the molecule:
The isomerism of various classes of organic compounds (interclass isomerism) is due to the different position and combination of atoms in the molecules of substances that have the same molecular formula, but belong to different classes. So, the molecular formula C6B12 corresponds to the unsaturated hydrocarbon hexene-1 and cyclic cyclohexane: 
Isomers of this type contain different functional groups and belong to different classes of substances. Therefore, they differ in physical and chemical properties much more than carbon skeleton isomers or position isomers.
Spatial isomerism
Spatial isomerism is divided into two types: geometric and optical.
Geometric isomerism is characteristic of compounds containing double bonds and cyclic compounds. Since free rotation of atoms around a double bond or in a cycle is impossible, substituents can be located either on one side of the plane of the double bond or cycle (cis position), or on opposite sides (trans position). The designations cis- and trans- usually refer to a pair of identical substituents. 
Geometric isomers differ in physical and chemical properties.
Optical isomerism occurs when a molecule is incompatible with its image in a mirror. This is possible when the carbon atom in the molecule has four different substituents. This atom is called asymmetric. An example of such a molecule is the α-aminopropionic acid (α-alanine) CH3CH(KH2)COOH molecule.
As can be seen, the α-alanine molecule cannot, under any movement, coincide with its mirror image. Such spatial isomers are called mirror, optical antipodes, or enantiomers. All physical and almost all chemical properties of such isomers are identical.
The study of optical isomerism is necessary when considering many reactions occurring in the body. Most of these reactions are under the action of enzymes - biological catalysts. The molecules of these substances must approach the molecules of the compounds on which they act like a key to a lock; therefore, the spatial structure, the relative position of the molecular regions, and other spatial factors are of great importance for the course of these reactions. Such reactions are called stereoselective.
Most natural compounds are individual enantiomers, and their biological action (from taste and smell to medicinal action) differs sharply from the properties of their optical antipodes obtained in the laboratory. Such a difference in biological activity is of great importance, since it underlies the most important property of all living organisms - metabolism.
What types of isomerism do you know?
What is the difference between structural isomerism and spatial isomerism?
Which of the proposed compounds are:
a) isomers;
b) homologues? 
Give all substances names.
4. Is geometric (cis-, trans) isomerism possible for: a) alkanes; b) alkenes; c) alkynes; d) cycloalkanes?
Explain, give examples. 
Since its properties depend on the structure and orientation of the molecule. Types of isomerism, as well as a feature of the structure of substances, are actively studied to this day.
Isomerism and isomerization: what is it?
Before considering the main types of isomerism, it is necessary to find out what this term means. It is generally accepted that isomerism is a phenomenon when chemical compounds (or isomers) differ in the structure and arrangement of atoms, but at the same time are characterized by the same composition and molecular weight.
In fact, the term "isomerization" appeared in science not so long ago. Several centuries ago, it was noticed that some substances with the same indicators and the same set of atoms differ in their properties.
An example is grape and In addition, at the beginning of the nineteenth century, a discussion ensued between the scientists J. Liebig and F. Wehler. In the course of numerous experiments, it was determined that there are two varieties of a substance with the formula AgCNO - silver fulminate and silver cyanate, which, despite the same composition, have different properties. Already in 1830, the concept of isomerization was introduced into science.
Later, thanks to the works of A. Butlerov and J. van't Hoff, the phenomena of spatial and structural isomerism were explained.
Isomerization is a specific reaction during which the transformation of structural isomers into each other is observed. As an example, we can take substances from the alkanes series. Structural types of isomerism of alkanes make it possible to convert some substances into isoalkanes. Thus, the industry increases fuel consumption. It is worth mentioning that such properties are of great importance for the development of industry.
Types of isomerism are usually divided into two large groups.
Structural isomerism and its varieties
Structural isomerism is a phenomenon in which isomers differ from each other. There are several separate types.
1. Isomerism of the carbon skeleton. This form is characteristic of carbons and is associated with a different order of bonds between carbon atoms.
2. Isomerism according to the position of the functional group. This phenomenon is due to the different position of the functional group or groups in the molecule. Examples include 4-chlorobutanoic and 2-chlorobutanoic acid.
3. Isomerism of multiple bonds. By the way, here we can include the most common types of isomerism of alkenes. Isomers differ in the position of the unsaturated bond.
4. Isomerism of the functional group. In this case, the general composition of the substance is preserved, but the properties and nature of the functional group itself change. An example is ethanol.
Spatial types of isomerism
Stereoisomerism (spatial) is associated with different orientations of molecules of the same structure.
1. Optical isomerism (enantiomerism). This form is associated with the rotation of functional groups around an asymmetric bond. In most cases, the substance has an asymmetric carbon atom, which is associated with four substituents. Thus, the plane rotates. As a result, the so-called mirror antipodes and isomers are formed. Interestingly, the latter are characterized by almost the same properties.
2. Diastereomerism. This term denotes such a spatial isomerism, as a result of which antipodal substances are not formed.
It should be noted that the presence of possible isomers is primarily related to the number of carbon bonds. The longer the carbon skeleton, the greater the number of isomers that can be formed.
There are two types of isomerism: structural and spatial (stereoisomerism). Structural isomers differ from each other in the order of bonds of atoms in a molecule, stereo-isomers - in the arrangement of atoms in space with the same order of bonds between them.
Structural isomerism: carbon skeleton isomerism, position isomerism, isomerism of various classes of organic compounds (interclass isomerism).
Structural isomerism
Isomerism of the carbon skeleton
Position isomerism is due to the different position of the multiple bond, substituent, functional group with the same carbon skeleton of the molecule: 
Spatial isomerism Spatial isomerism is divided into two types: geometric and optical.
Geometric isomerism is characteristic of compounds containing double bonds and cyclic compounds. Since free rotation of atoms around a double bond or in a cycle is impossible, substituents can be located either on one side of the plane of the double bond or cycle (cis position), or on opposite sides (trans position). 
Optical isomerism occurs when a molecule is incompatible with its image in a mirror. This is possible when the carbon atom in the molecule has four different substituents. This atom is called asymmetric. 
CHIRALITY, the property of an object to be incompatible with its reflection in an ideal flat mirror.
Various spatial structures that arise due to rotation around simple bonds without violating the integrity of the molecule (without breaking chemical bonds) are called CONFORMATIONS.
8. The structure of alkanes. Sp3 is the state of carbon. Characteristics of connections with-with and with-n. The principle of free rotation. conformation. Methods of representation and nomenclature. Physical properties of alkanes.
All carbon atoms in alkane molecules are in the state sp 3
- hybridization, the angle between the C-C bonds is 109 ° 28 ", therefore, the molecules of normal alkanes with a large number of carbon atoms have a zigzag structure (zigzag). The C-C bond length in saturated hydrocarbons is 0.154 nm 
The C-C bond is covalent non-polar. The C-H bond is covalent and weakly polar, as C and H are close in electronegativity.
Physical properties
Under normal conditions, the first four members of the homologous series of alkanes are gases, C 5 -C 17 are liquids, and starting from C 18 are solids. The melting and boiling points of alkanes and their densities increase with increasing molecular weight. All alkanes are lighter than water, insoluble in it, but soluble in non-polar solvents (for example, in benzene) and are themselves good solvents.
The melting and boiling points decrease from less branched to more branched.
Gaseous alkanes burn with a colorless or pale blue flame, releasing a large amount of heat.
The rotation of atoms around the s-bond will not break it. As a result of intramolecular rotation along C–C s-bonds, alkane molecules, starting from C 2 H 6 ethane, can take different geometric shapes. Various spatial forms of a molecule, passing into each other by rotation around C–C s-bonds, are called conformations or rotational isomers(conformers). The rotational isomers of a molecule are its energetically unequal states. Their interconversion occurs quickly and constantly as a result of thermal motion. Therefore, rotational isomers cannot be isolated individually, but their existence has been proven by physical methods.
alkanes . methane, ethane, propane, butane –en
9. Hydrocarbons. Classification. Limit hydrocarbons of the methane series. homologous series. Nomenclature. Isomerism. Radicals. natural sources. Fischer-Tropsch synthesis. Preparation methods (from alkenes, carboxylic acids, halogen derivatives, by the Wurtz reaction)
General (generic) name of saturated hydrocarbons - alkanes . The names of the first four members of the homologous series of methane are trivial: methane, ethane, propane, butane . Starting from the fifth name, they are formed from Greek numerals with the addition of a suffix –en
Radicals (hydrocarbon radicals) also have their own nomenclature. Monovalent radicals are called alkyls and are denoted by the letter R or Alk. Their general formula is C n H 2n+ 1 . The names of the radicals are formed from the names of the corresponding hydrocarbons by replacing the suffix -an to suffix -silt(methane - methyl, ethane - ethyl, propane - propyl, etc.). Divalent radicals are named by changing the suffix -an on -ylidene(an exception is the methylene radical == CH 2). Trivalent radicals have the suffix -ylidine
Isomerism. Alkanes are characterized by structural isomerism. If an alkane molecule contains more than three carbon atoms, then the order of their connection may be different. One of the isomers of butane ( n-butane) contains an unbranched carbon chain, and the other - isobutane - branched (isostructure).
The most important source of alkanes in nature is natural gas, mineral hydrocarbon raw materials - oil and associated petroleum gases.
The production of alkanes can be carried out by the Wurtz reaction, which consists in the action of metallic sodium on monohalogen derivatives of hydrocarbons. 2CH 3 -CH 2 Br (ethyl bromide) + 2Na -–> CH 3 -CH 2 -CH 2 -CH 3 (butane) + 2NaBr
From alkenes
C n H 2n + H 2 → C n H 2n+2
Fischer-Tropsch synthesis
nCO + (2n+1)H 2 → C n H 2n+2 + nH 2 O
The table shows that these hydrocarbons differ from each other in the number of groups - CH2-. Such a series of similar in structure, having similar chemical properties and differing from each other in the number of these groups is called a homologous series. And the substances that make it up are called homologues.
|
Name |
|
|
isobutane |
|
|
isopentane |
|
|
neopentane |
|
