Compounds containing only carbon and hydrogen atoms.

Hydrocarbons are divided into cyclic (carbocyclic compounds) and acyclic.

Cyclic (carbocyclic) compounds are called compounds that include one or more cycles consisting only of carbon atoms (as opposed to heterocyclic compounds containing heteroatoms - nitrogen, sulfur, oxygen, etc.). Carbocyclic compounds, in turn, are divided into aromatic and non-aromatic (alicyclic) compounds.

Acyclic hydrocarbons include organic compounds whose carbon skeleton of molecules is open chains.

These chains can be formed by single bonds (al-kanes), contain one double bond (alkenes), two or more double bonds (dienes or polyenes), one triple bond (alkynes).

As you know, carbon chains are part of most organic substances. Thus, the study of hydrocarbons is of particular importance, since these compounds are the structural basis of other classes of organic compounds.

In addition, hydrocarbons, especially alkanes, are the main natural sources of organic compounds and the basis of the most important industrial and laboratory syntheses (Scheme 1).

You already know that hydrocarbons are the most important feedstock for the chemical industry. In turn, hydrocarbons are quite widespread in nature and can be isolated from various natural sources: oil, associated petroleum and natural gas, coal. Let's consider them in more detail.

Oil- a natural complex mixture of hydrocarbons, mainly linear and branched alkanes, containing from 5 to 50 carbon atoms in molecules, with other organic substances. Its composition significantly depends on the place of its production (deposit), it can, in addition to alkanes, contain cycloalkanes and aromatic hydrocarbons.

Gaseous and solid components of oil are dissolved in its liquid components, which determines its state of aggregation. Oil is an oily liquid of dark (from brown to black) color with a characteristic odor, insoluble in water. Its density is less than that of water, therefore, getting into it, oil spreads over the surface, preventing the dissolution of oxygen and other air gases in water. Obviously, getting into natural water bodies, oil causes the death of microorganisms and animals, leading to environmental disasters and even catastrophes. There are bacteria that can use the components of oil as food, converting it into harmless products of their vital activity. It is clear that the use of cultures of these bacteria is the most environmentally safe and promising way to combat oil pollution in the process of its extraction, transportation and processing.

In nature, oil and associated petroleum gas, which will be discussed below, fill the cavities of the earth's interior. Being a mixture of various substances, oil does not have a constant boiling point. It is clear that each of its components retains its individual physical properties in the mixture, which makes it possible to separate the oil into its components. To do this, it is purified from mechanical impurities, sulfur-containing compounds and subjected to the so-called fractional distillation, or rectification.

Fractional distillation is a physical method for separating a mixture of components with different boiling points.

Distillation is carried out in special installations - distillation columns, in which the cycles of condensation and evaporation of liquid substances contained in oil are repeated (Fig. 9).

Vapors formed during the boiling of a mixture of substances are enriched with a lighter-boiling (i.e., having a lower temperature) component. These vapors are collected, condensed (cooled to below boiling point) and brought back to a boil. In this case, vapors are formed that are even more enriched with a low-boiling substance. By repeated repetition of these cycles, it is possible to achieve almost complete separation of the substances contained in the mixture.

The distillation column receives oil heated in a tubular furnace to a temperature of 320-350 °C. The distillation column has horizontal partitions with holes - the so-called plates, on which the oil fractions condense. Light-boiling fractions accumulate on the higher ones, high-boiling fractions on the lower ones.

In the process of rectification, oil is divided into the following fractions:

Rectification gases - a mixture of low molecular weight hydrocarbons, mainly propane and butane, with a boiling point of up to 40 ° C;

Gasoline fraction (gasoline) - hydrocarbons of composition from C 5 H 12 to C 11 H 24 (boiling point 40-200 ° C); with a finer separation of this fraction, gasoline (petroleum ether, 40-70 ° C) and gasoline (70-120 ° C) are obtained;

Naphtha fraction - hydrocarbons of composition from C8H18 to C14H30 (boiling point 150-250 ° C);

Kerosene fraction - hydrocarbons of composition from C12H26 to C18H38 (boiling point 180-300 ° C);

Diesel fuel - hydrocarbons of composition from C13H28 to C19H36 (boiling point 200-350 ° C).

Residue of oil distillation - fuel oil- contains hydrocarbons with the number of carbon atoms from 18 to 50. Distillation under reduced pressure from fuel oil produces solar oil (C18H28-C25H52), lubricating oils (C28H58-C38H78), vaseline and paraffin - fusible mixtures of solid hydrocarbons. The solid residue of fuel oil distillation - tar and its processing products - bitumen and asphalt are used for the manufacture of road surfaces.

The products obtained as a result of oil rectification are subjected to chemical processing, which includes a number of complex processes. One of them is the cracking of petroleum products. You already know that fuel oil is separated into components under reduced pressure. This is due to the fact that at atmospheric pressure, its components begin to decompose before reaching the boiling point. This is what underlies cracking.

Cracking - thermal decomposition of petroleum products, leading to the formation of hydrocarbons with a smaller number of carbon atoms in the molecule.

There are several types of cracking: thermal cracking, catalytic cracking, high pressure cracking, reduction cracking.

Thermal cracking consists in the splitting of hydrocarbon molecules with a long carbon chain into shorter ones under the influence of high temperature (470-550 ° C). In the process of this splitting, along with alkanes, alkenes are formed.

In general, this reaction can be written as follows:

C n H 2n+2 -> C n-k H 2(n-k)+2 + C k H 2k
alkane alkane alkene
long chain

The resulting hydrocarbons can be cracked again to form alkanes and alkenes with an even shorter chain of carbon atoms in the molecule:

During conventional thermal cracking, many low molecular weight gaseous hydrocarbons are formed, which can be used as raw materials for the production of alcohols, carboxylic acids, and high molecular weight compounds (for example, polyethylene).

catalytic cracking occurs in the presence of catalysts, which are used as natural aluminosilicates of the composition

The implementation of cracking using catalysts leads to the formation of hydrocarbons having a branched or closed chain of carbon atoms in the molecule. The content of hydrocarbons of this structure in motor fuel significantly improves its quality, primarily knock resistance - the octane number of gasoline.

Cracking of petroleum products proceeds at high temperatures, so carbon deposits (soot) are often formed, contaminating the surface of the catalyst, which sharply reduces its activity.

Cleaning the catalyst surface from carbon deposits - its regeneration - is the main condition for the practical implementation of catalytic cracking. The simplest and cheapest way to regenerate a catalyst is its roasting, during which carbon deposits are oxidized by atmospheric oxygen. Gaseous oxidation products (mainly carbon dioxide and sulfur dioxide) are removed from the catalyst surface.

Catalytic cracking is a heterogeneous process involving solid (catalyst) and gaseous (hydrocarbon vapor) substances. It is obvious that the regeneration of the catalyst - the interaction of solid deposits with atmospheric oxygen - is also a heterogeneous process.

heterogeneous reactions(gas - solid) flow faster as the surface area of ​​the solid increases. Therefore, the catalyst is crushed, and its regeneration and cracking of hydrocarbons are carried out in a "fluidized bed", familiar to you from the production of sulfuric acid.

The cracking feedstock, such as gas oil, enters the conical reactor. The lower part of the reactor has a smaller diameter, so the feed vapor flow rate is very high. The gas moving at high speed captures the catalyst particles and carries them to the upper part of the reactor, where, due to the increase in its diameter, the flow rate decreases. Under the action of gravity, the catalyst particles fall into the lower, narrower part of the reactor, from where they are again carried upwards. Thus, each grain of the catalyst is in constant motion and is washed from all sides by a gaseous reagent.

Some catalyst grains enter the outer, wider part of the reactor and, without encountering gas flow resistance, descend to the lower part, where they are picked up by the gas flow and carried away to the regenerator. There, too, in the "fluidized bed" mode, the catalyst is burned and returned to the reactor.

Thus, the catalyst circulates between the reactor and the regenerator, and the gaseous products of cracking and roasting are removed from them.

The use of cracking catalysts makes it possible to slightly increase the reaction rate, reduce its temperature, and improve the quality of cracked products.

The obtained hydrocarbons of the gasoline fraction mainly have a linear structure, which leads to a low knock resistance of the obtained gasoline.

We will consider the concept of "knock resistance" later, for now we only note that hydrocarbons with branched molecules have a much greater detonation resistance. It is possible to increase the proportion of isomeric branched hydrocarbons in the mixture formed during cracking by adding isomerization catalysts to the system.

Oil fields contain, as a rule, large accumulations of the so-called associated petroleum gas, which collects above the oil in the earth's crust and partially dissolves in it under the pressure of the overlying rocks. Like oil, associated petroleum gas is a valuable natural source of hydrocarbons. It contains mainly alkanes, which have from 1 to 6 carbon atoms in their molecules. Obviously, the composition of associated petroleum gas is much poorer than oil. However, despite this, it is also widely used both as a fuel and as a raw material for the chemical industry. Until a few decades ago, in most oil fields, associated petroleum gas was burned as a useless addition to oil. At present, for example, in Surgut, Russia's richest oil pantry, the world's cheapest electricity is generated using associated petroleum gas as fuel.

As already noted, associated petroleum gas is richer in composition in various hydrocarbons than natural gas. Dividing them into fractions, they get:

Natural gasoline - a highly volatile mixture consisting mainly of lentane and hexane;

Propane-butane mixture, consisting, as the name implies, of propane and butane and easily turns into a liquid state when pressure increases;

Dry gas - a mixture containing mainly methane and ethane.

Natural gasoline, being a mixture of volatile components with a small molecular weight, evaporates well even at low temperatures. This makes it possible to use gas gasoline as a fuel for internal combustion engines in the Far North and as an additive to motor fuel, which makes it easier to start engines in winter conditions.

A propane-butane mixture in the form of liquefied gas is used as household fuel (gas cylinders familiar to you in the country) and for filling lighters. The gradual transition of road transport to liquefied gas is one of the main ways to overcome the global fuel crisis and solve environmental problems.

Dry gas, close in composition to natural gas, is also widely used as a fuel.

However, the use of associated petroleum gas and its components as a fuel is far from the most promising way to use it.

It is much more efficient to use associated petroleum gas components as feedstock for chemical production. Hydrogen, acetylene, unsaturated and aromatic hydrocarbons and their derivatives are obtained from alkanes, which are part of associated petroleum gas.

Gaseous hydrocarbons can not only accompany oil in the earth's crust, but also form independent accumulations - natural gas deposits.

Natural gas - a mixture of gaseous saturated hydrocarbons with a small molecular weight. The main component of natural gas is methane, the share of which, depending on the field, ranges from 75 to 99% by volume. In addition to methane, natural gas contains ethane, propane, butane and isobutane, as well as nitrogen and carbon dioxide.

Like associated petroleum gas, natural gas is used both as a fuel and as a raw material for the production of various organic and inorganic substances. You already know that hydrogen, acetylene and methyl alcohol, formaldehyde and formic acid, and many other organic substances are obtained from methane, the main component of natural gas. As a fuel, natural gas is used in power plants, in boiler systems for water heating of residential buildings and industrial buildings, in blast furnace and open-hearth production. Striking a match and igniting gas in the kitchen gas stove of a city house, you "start" a chain reaction of oxidation of alkanes that are part of natural gas. In addition to oil, natural and associated petroleum gases, coal is a natural source of hydrocarbons. 0n forms powerful layers in the bowels of the earth, its explored reserves significantly exceed oil reserves. Like oil, coal contains a large amount of various organic substances. In addition to organic, it also includes inorganic substances, such as water, ammonia, hydrogen sulfide and, of course, carbon itself - coal. One of the main ways of coal processing is coking - calcination without air access. As a result of coking, which is carried out at a temperature of about 1000 ° C, the following are formed:

Coke oven gas, which includes hydrogen, methane, carbon monoxide and carbon dioxide, impurities of ammonia, nitrogen and other gases;
coal tar containing several hundred different organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds;
supra-tar, or ammonia water, containing, as the name implies, dissolved ammonia, as well as phenol, hydrogen sulfide and other substances;
coke - solid residue of coking, almost pure carbon.

coke used in the production of iron and steel, ammonia - in the production of nitrogen and combined fertilizers, and the importance of organic coking products can hardly be overestimated.

Thus, associated petroleum and natural gases, coal are not only the most valuable sources of hydrocarbons, but also part of the unique pantry of irreplaceable natural resources, the careful and reasonable use of which is a necessary condition for the progressive development of human society.

1. List the main natural sources of hydrocarbons. What organic substances are included in each of them? What do they have in common?

2. Describe the physical properties of oil. Why doesn't it have a constant boiling point?

3. After summarizing the media reports, describe the environmental disasters caused by the oil spill and how to overcome their consequences.

4. What is rectification? What is this process based on? Name the fractions obtained as a result of oil rectification. How do they differ from each other?

5. What is cracking? Give the equations of three reactions corresponding to the cracking of petroleum products.

6. What types of cracking do you know? What do these processes have in common? How do they differ from each other? What is the fundamental difference between different types of cracked products?

7. Why is associated petroleum gas so named? What are its main components and their uses?

8. How does natural gas differ from associated petroleum gas? What do they have in common? Give the equations of combustion reactions of all components of associated petroleum gas known to you.

9. Give the reaction equations that can be used to obtain benzene from natural gas. Specify the conditions for these reactions.

10. What is coking? What are its products and their composition? Give the equations of the reactions typical for the products of coal coking known to you.

11. Explain why burning oil, coal and associated petroleum gas is far from being the most rational way to use them.

Dry distillation of coal.

Aromatic hydrocarbons are obtained mainly from the dry distillation of coal. When coal is heated in retorts or coking ovens without air at 1000–1300 °C, the organic matter of coal decomposes to form solid, liquid, and gaseous products.

The solid product of dry distillation - coke - is a porous mass consisting of carbon with an admixture of ash. Coke is produced in huge quantities and consumed mainly by the metallurgical industry as a reducing agent in the production of metals (primarily iron) from ores.

The liquid products of dry distillation are black viscous tar (coal tar), and the aqueous layer containing ammonia is ammonia water. Coal tar is obtained on average 3% of the mass of the original coal. Ammonia water is one of the important sources of ammonia production. Gaseous products of dry distillation of coal are called coke gas. Coke oven gas has a different composition depending on the grade of coal, coking mode, etc. Coke gas produced in coke oven batteries is passed through a series of absorbers that trap tar, ammonia and light oil vapors. Light oil obtained by condensation from coke oven gas contains 60% benzene, toluene and other hydrocarbons. Most of the benzene (up to 90%) is obtained in this way and only a little - by fractionation of coal tar.

Processing of coal tar. Coal tar has the appearance of a black resinous mass with a characteristic odor. Currently, more than 120 different products have been isolated from coal tar. Among them are aromatic hydrocarbons, as well as aromatic oxygen-containing substances of an acidic nature (phenols), nitrogen-containing substances of a basic nature (pyridine, quinoline), substances containing sulfur (thiophene), etc.

Coal tar is subjected to fractional distillation, as a result of which several fractions are obtained.

Light oil contains benzene, toluene, xylenes and some other hydrocarbons. Medium, or carbolic, oil contains a number of phenols.

Heavy, or creosote, oil: Of the hydrocarbons in heavy oil, naphthalene is contained.

Getting hydrocarbons from oil Oil is one of the main sources of aromatic hydrocarbons. Most species

oil contains only a very small amount of aromatic hydrocarbons. From domestic oil rich in aromatic hydrocarbons is the oil of the Ural (Perm) field. The oil of the "Second Baku" contains up to 60% aromatic hydrocarbons.

Due to the scarcity of aromatic hydrocarbons, “oil flavoring” is now used: oil products are heated at a temperature of about 700 ° C, as a result of which 15–18% of aromatic hydrocarbons can be obtained from the decomposition products of oil.

32. Synthesis, physical and chemical properties of aromatic hydrocarbons

1. Synthesis from aromatic hydrocarbons and fatty halo derivatives in the presence of catalysts (Friedel-Crafts synthesis).

2. Synthesis from salts of aromatic acids.

When dry salts of aromatic acids are heated with soda lime, the salts decompose to form hydrocarbons. This method is similar to the production of fatty hydrocarbons.

3. Synthesis from acetylene. This reaction is of interest as an example of the synthesis of benzene from fatty hydrocarbons.

When acetylene is passed through a heated catalyst (at 500 °C), the triple bonds of acetylene are broken and three of its molecules polymerize into one benzene molecule.

Physical properties Aromatic hydrocarbons are liquids or solids with

characteristic odour. Hydrocarbons with no more than one benzene ring in their molecules are lighter than water. Aromatic hydrocarbons are slightly soluble in water.

The IR spectra of aromatic hydrocarbons are primarily characterized by three regions:

1) about 3000 cm-1, due to C-H stretching vibrations;

2) the 1600–1500 cm-1 region associated with skeletal vibrations of aromatic carbon-carbon bonds and significantly varying in peak positions depending on the structure;

3) the area below 900 cm-1 related to the bending vibrations of C-H of the aromatic ring.

Chemical properties The most important general chemical properties of aromatic hydrocarbons are

their tendency to substitution reactions and the high strength of the benzene nucleus.

Benzene homologues have a benzene core and a side chain in their molecule, for example, in the hydrocarbon C 6 H5 -C2 H5, the C6 H5 group is the benzene core, and C2 H5 is the side chain. Properties

benzene ring in the molecules of benzene homologues approach the properties of benzene itself. The properties of the side chains, which are residues of fatty hydrocarbons, approach the properties of fatty hydrocarbons.

The reactions of benzene hydrocarbons can be divided into four groups.

33. Orientation rules in the benzene nucleus

When studying substitution reactions in the benzene nucleus, it was found that if the benzene nucleus already contains any substituent group, then the second group enters a certain position depending on the nature of the first substituent. Thus, each substituent in the benzene nucleus has a certain directing, or orienting, action.

The position of the newly introduced substituent is also influenced by the nature of the substituent itself, i.e., the electrophilic or nucleophilic nature of the active reagent. The vast majority of the most important substitution reactions in the benzene ring are electrophilic substitution reactions (replacement of a hydrogen atom split off in the form of a proton by a positively charged particle) - halogenation, sulfonation, nitration reactions, etc.

All substitutes are divided into two groups according to the nature of their guiding action.

1. Substituents of the first kind in reactions electrophilic substitution direct subsequent introduced groups to the ortho- and para-positions.

Substituents of this kind include, for example, the following groups, arranged in descending order of their directing power: -NH2, -OH, -CH3.

2. Substituents of the second kind in reactions electrophilic substitution direct subsequent introduced groups to the meta position.

Substituents of this kind include the following groups, arranged in descending order of their directing force: -NO2, -C≡N, -SO3 H.

Substituents of the first kind contain single bonds; substituents of the second kind are characterized by the presence of double or triple bonds.

Substituents of the first kind in the overwhelming majority of cases facilitate substitution reactions. For example, to nitrate benzene, you need to heat it with a mixture of concentrated nitric and sulfuric acids, while phenol C6 H5 OH can be successfully

nitrate with dilute nitric acid at room temperature to form ortho- and paranitrophenol.

Substituents of the second kind generally hinder substitution reactions altogether. Particularly difficult is the substitution in the ortho- and para-positions, and the substitution in the meta-position is relatively easier.

Currently, the influence of substituents is explained by the fact that substituents of the first kind are electron-donating (donating electrons), i.e., their electron clouds are shifted towards the benzene nucleus, which increases the reactivity of hydrogen atoms.

An increase in the reactivity of hydrogen atoms in the ring facilitates the course of electrophilic substitution reactions. So, for example, in the presence of hydroxyl, the free electrons of the oxygen atom are shifted towards the ring, which increases the electron density in the ring, and the electron density of carbon atoms in the ortho and para positions to the substituent especially increases.

34. Substitution rules in the benzene nucleus

The rules of substitution in the benzene ring are of great practical importance, since they make it possible to predict the course of the reaction and choose the correct path for the synthesis of one or another desired substance.

The mechanism of electrophilic substitution reactions in the aromatic series. Modern research methods have made it possible to largely elucidate the mechanism of substitution in the aromatic series. Interestingly, in many respects, especially at the first stages, the mechanism of electrophilic substitution in the aromatic series turned out to be similar to the mechanism of electrophilic addition in the fatty series.

The first step in electrophilic substitution is (as in electrophilic addition) the formation of a p-complex. The electrophilic particle Xd+ binds to all six p-electrons of the benzene ring.

The second stage is the formation of the p-complex. In this case, the electrophilic particle "pulls out" two electrons from six p-electrons to form an ordinary covalent bond. The resulting p-complex no longer has an aromatic structure: it is an unstable carbocation in which four p-electrons in a delocalized state are distributed between five carbon atoms, while the sixth carbon atom passes into a saturated state. The introduced substituent X and the hydrogen atom are in a plane perpendicular to the plane of the six-membered ring. The S-complex is an intermediate whose formation and structure have been proven by a number of methods, in particular by spectroscopy.

The third stage of electrophilic substitution is the stabilization of the S-complex, which is achieved by the elimination of a hydrogen atom in the form of a proton. The two electrons involved in the formation of the C-H bond, after the removal of a proton, together with four delocalized electrons of five carbon atoms, give the usual stable aromatic structure of substituted benzene. The role of the catalyst (usually A 1 Cl3) in this case

The process consists in strengthening the polarization of haloalkyl with the formation of a positively charged particle, which enters into an electrophilic substitution reaction.

Addition Reactions Benzene hydrocarbons react with great difficulty

decolorize with bromine water and KMnO4 solution. However, under special reaction conditions

connections are still possible. 1. Addition of halogens.

Oxygen in this reaction plays the role of a negative catalyst: in its presence, the reaction does not proceed. Hydrogen addition in the presence of a catalyst:

C6 H6 + 3H2 → C6 H12

2. Oxidation of aromatic hydrocarbons.

Benzene itself is exceptionally resistant to oxidation - more resistant than paraffins. Under the action of energetic oxidizing agents (KMnO4 in an acidic medium, etc.) on benzene homologues, the benzene core is not oxidized, while the side chains undergo oxidation with the formation of aromatic acids.

Natural sources of hydrocarbons are fossil fuels - oil and

gas, coal and peat. Crude oil and gas deposits arose 100-200 million years ago

back from microscopic marine plants and animals that turned out to be

included in the sedimentary rocks formed at the bottom of the sea, Unlike

that coal and peat began to form 340 million years ago from plants,

growing on dry land.

Natural gas and crude oil are usually found along with water in

oil-bearing layers located between layers of rocks (Fig. 2). Term

"natural gas" also applies to gases that are formed in natural

conditions as a result of the decomposition of coal. Natural gas and crude oil

developed on all continents except Antarctica. the largest

natural gas producers in the world are Russia, Algeria, Iran and

United States. The largest producers of crude oil are

Venezuela, Saudi Arabia, Kuwait and Iran.

Natural gas consists mainly of methane (Table 1).

Crude oil is an oily liquid, the color of which can

be the most diverse - from dark brown or green to almost

colorless. It contains a large number of alkanes. Among them are

straight chain alkanes, branched alkanes and cycloalkanes with the number of atoms

carbon five to 40. The industrial name for these cycloalkanes is numbered. AT

crude oil, in addition, contains approximately 10% aromatic

hydrocarbons, as well as a small amount of other compounds containing

sulfur, oxygen and nitrogen.

Table 1 Composition of natural gas

Coal is the oldest source of energy known to

humanity. It is a mineral (Fig. 3), which was formed from

plant matter during metamorphism. Metamorphic

called rocks, the composition of which has undergone changes in conditions

high pressures and high temperatures. The product of the first stage in

process of formation of coal is peat, which is

decomposed organic matter. Coal is formed from peat after

it is covered with sedimentary rocks. These sedimentary rocks are called

overloaded. Overloaded precipitation reduces the moisture content of peat.

Three criteria are used in the classification of coals: purity (determined by

relative carbon content in percent); type (defined

the composition of the original plant matter); grade (depending on

degree of metamorphism).

Table 2 Carbon content in some types of fuel and their calorific value

ability

The lowest grade fossil coals are lignite and

lignite (Table 2). They are closest to peat and are characterized by relatively

characterized by a lower moisture content and is widely used in

industry. The driest and hardest grade of coal is anthracite. His

used for home heating and cooking.

In recent years, thanks to technological advances, it is becoming more and more

economical gasification of coal. Coal gasification products include

carbon monoxide, carbon dioxide, hydrogen, methane and nitrogen. They are used in

as a gaseous fuel or as a raw material for the production of various

chemicals and fertilizers.

Coal, as discussed below, is an important source of raw materials for

aromatic compounds. Coal Represents

a complex mixture of chemicals, which include carbon,

hydrogen and oxygen, as well as small amounts of nitrogen, sulfur and other impurities

elements. In addition, the composition of coal, depending on its grade, includes

varying amounts of moisture and various minerals.

Hydrocarbons occur naturally not only in fossil fuels, but also in

in some materials of biological origin. natural rubber

is an example of a natural hydrocarbon polymer. rubber molecule

consists of thousands of structural units, which are methylbuta-1,3-diene

(isoprene);

natural rubber. Approximately 90% natural rubber, which

currently mined all over the world, obtained from the Brazilian

rubber tree Hevea brasiliensis, cultivated mainly in

equatorial countries of Asia. The sap of this tree, which is latex

(a colloidal aqueous solution of polymer), collected from incisions made with a knife on

bark. Latex contains approximately 30% rubber. Its tiny pieces

suspended in water. The juice is poured into aluminum containers, where acid is added,

causing the rubber to coagulate.

Many other natural compounds also contain isoprene structural

fragments. For example, limonene contains two isoprene moieties. Limonene

is the main component of oils extracted from the peel of citrus fruits,

such as lemons and oranges. This connection belongs to the class of connections,

called terpenes. Terpenes contain 10 carbon atoms in their molecules (C

10-compounds) and include two isoprene fragments connected to each other

the other sequentially (“head to tail”). Compounds with four isoprene

fragments (C 20 compounds) are called diterpenes, and with six

isoprene fragments - triterpenes (C 30 compounds). Squalene

found in shark liver oil is a triterpene.

Tetraterpenes (C 40 compounds) contain eight isoprene

fragments. Tetraterpenes are found in the pigments of vegetable and animal fats.

origin. Their coloration is due to the presence of a long conjugated system

double bonds. For example, β-carotene is responsible for the characteristic orange

coloring of carrots.

Oil and coal processing technology

At the end of the XIX century. under the influence of progress in the field of thermal power engineering, transport, engineering, military and a number of other industries, demand has increased immeasurably and an urgent need has arisen for new types of fuel and chemical products.

At this time, the oil refining industry was born and rapidly progressed. A huge impetus to the development of the oil refining industry was given by the invention and rapid spread of the internal combustion engine running on petroleum products. The technique of processing coal, which is not only one of the main types of fuel, but, which is especially noteworthy, became an essential raw material for the chemical industry during the period under review, also developed intensively. A large role in this matter belonged to coke chemistry. Coke plants, which previously supplied coke to the ferrous metallurgy, turned into coke-chemical enterprises, which, in addition, produced a number of valuable chemical products: coke oven gas, crude benzene, coal tar and ammonia.

The production of synthetic organic substances and materials began to develop on the basis of oil and coal processing products. They are widely used as raw materials and semi-finished products in various branches of the chemical industry.

Ticket number 10

Target. Generalize knowledge about natural sources of organic compounds and their processing; show the successes and prospects for the development of petrochemistry and coke chemistry, their role in the technical progress of the country; deepen knowledge from the course of economic geography about the gas industry, modern directions of gas processing, raw materials and energy problems; develop independence in working with a textbook, reference and popular science literature.

PLAN

Natural sources of hydrocarbons. Natural gas. Associated petroleum gases.
Oil and oil products, their application.
Thermal and catalytic cracking.
Coke production and the problem of obtaining liquid fuel.
From the history of the development of OJSC Rosneft-KNOS.
The production capacity of the plant. Manufactured products.
Communication with the chemical laboratory.
Environmental protection in the factory.
Plant plans for the future.

Natural sources of hydrocarbons.
Natural gas. Associated petroleum gases

Before the Great Patriotic War, industrial stocks natural gas were known in the Carpathian region, in the Caucasus, in the Volga region and in the North (Komi ASSR). The study of natural gas reserves was associated only with oil exploration. Industrial reserves of natural gas in 1940 amounted to 15 billion m 3 . Then gas fields were discovered in the North Caucasus, Transcaucasia, Ukraine, the Volga region, Central Asia, Western Siberia and the Far East. On the
On January 1, 1976, explored reserves of natural gas amounted to 25.8 trillion m 3, of which 4.2 trillion m 3 (16.3%) in the European part of the USSR, 21.6 trillion m 3 (83.7 %), including
18.2 trillion m 3 (70.5%) - in Siberia and the Far East, 3.4 trillion m 3 (13.2%) - in Central Asia and Kazakhstan. As of January 1, 1980, potential reserves of natural gas amounted to 80–85 trillion m 3 , explored - 34.3 trillion m 3 . Moreover, the reserves increased mainly due to the discovery of deposits in the eastern part of the country - explored reserves there were at a level of about
30.1 trillion m 3, which was 87.8% of the all-Union.
Today, Russia has 35% of the world's natural gas reserves, which is more than 48 trillion m 3 . The main areas of occurrence of natural gas in Russia and the CIS countries (fields):

West Siberian oil and gas province:
Urengoyskoye, Yamburgskoye, Zapolyarnoye, Medvezhye, Nadymskoye, Tazovskoye – Yamalo-Nenets Autonomous Okrug;
Pokhromskoye, Igrimskoye - Berezovskaya gas-bearing region;
Meldzhinskoye, Luginetskoye, Ust-Silginskoye - Vasyugan gas-bearing region.
Volga-Ural oil and gas province:
the most significant is Vuktylskoye, in the Timan-Pechora oil and gas region.
Central Asia and Kazakhstan:
the most significant in Central Asia is Gazli, in the Ferghana Valley;
Kyzylkum, Bairam-Ali, Darvaza, Achak, Shatlyk.
North Caucasus and Transcaucasia:
Karadag, Duvanny - Azerbaijan;
Dagestan Lights - Dagestan;
Severo-Stavropolskoye, Pelagiadinskoye - Stavropol Territory;
Leningradskoye, Maykopskoye, Staro-Minskoye, Berezanskoye - Krasnodar Territory.

Also, natural gas deposits are known in Ukraine, Sakhalin and the Far East.
In terms of natural gas reserves, Western Siberia stands out (Urengoyskoye, Yamburgskoye, Zapolyarnoye, Medvezhye). Industrial reserves here reach 14 trillion m 3 . The Yamal gas condensate fields (Bovanenkovskoye, Kruzenshternskoye, Kharasaveyskoye, etc.) are now acquiring particular importance. On their basis, the Yamal-Europe project is being implemented.
Natural gas production is highly concentrated and focused on areas with the largest and most profitable deposits. Only five deposits - Urengoyskoye, Yamburgskoye, Zapolyarnoye, Medvezhye and Orenburgskoye - contain 1/2 of all industrial reserves of Russia. The reserves of Medvezhye are estimated at 1.5 trillion m 3 , and those of Urengoy – at 5 trillion m 3 .
The next feature is the dynamic location of natural gas production sites, which is explained by the rapid expansion of the boundaries of the identified resources, as well as the relative ease and cheapness of their involvement in development. In a short time, the main centers for the extraction of natural gas moved from the Volga region to Ukraine, the North Caucasus. Further territorial shifts were caused by the development of deposits in Western Siberia, Central Asia, the Urals and the North.

After the collapse of the USSR in Russia, there was a drop in the volume of natural gas production. The decline was observed mainly in the Northern economic region (8 billion m 3 in 1990 and 4 billion m 3 in 1994), in the Urals (43 billion m 3 and 35 billion m and
555 billion m 3) and in the North Caucasus (6 and 4 billion m 3). Natural gas production remained at the same level in the Volga region (6 bcm) and in the Far East economic regions.
At the end of 1994, there was an upward trend in production levels.
Of the republics of the former USSR, the Russian Federation provides the most gas, in second place is Turkmenistan (more than 1/10), followed by Uzbekistan and Ukraine.
Of particular importance is the extraction of natural gas on the shelf of the World Ocean. In 1987, offshore fields produced 12.2 billion m 3 , or about 2% of the gas produced in the country. Associated gas production in the same year amounted to 41.9 bcm. For many areas, one of the reserves of gaseous fuel is the gasification of coal and shale. Underground gasification of coal is carried out in the Donbass (Lysichansk), Kuzbass (Kiselevsk) and the Moscow Basin (Tula).
Natural gas has been and remains an important export product in Russian foreign trade.
The main natural gas processing centers are located in the Urals (Orenburg, Shkapovo, Almetyevsk), in Western Siberia (Nizhnevartovsk, Surgut), in the Volga region (Saratov), ​​in the North Caucasus (Grozny) and in other gas-bearing provinces. It can be noted that gas processing plants tend to sources of raw materials - deposits and large gas pipelines.
The most important use of natural gas is as a fuel. Recently, there has been a trend towards an increase in the share of natural gas in the country's fuel balance.

The most valued natural gas with a high content of methane is Stavropol (97.8% CH 4), Saratov (93.4%), Urengoy (95.16%).
Natural gas reserves on our planet are very large (approximately 1015 m 3). More than 200 deposits are known in Russia, they are located in Western Siberia, in the Volga-Ural basin, in the North Caucasus. Russia holds the first place in the world in terms of natural gas reserves.
Natural gas is the most valuable type of fuel. When gas is burned, a lot of heat is released, so it serves as an energy efficient and cheap fuel in boiler plants, blast furnaces, open-hearth furnaces and glass melting furnaces. The use of natural gas in production makes it possible to significantly increase labor productivity.
Natural gas is a source of raw materials for the chemical industry: the production of acetylene, ethylene, hydrogen, soot, various plastics, acetic acid, dyes, medicines and other products.

Associated petroleum gas- this is a gas that exists together with oil, it is dissolved in oil and is located above it, forming a "gas cap", under pressure. At the exit from the well, the pressure drops, and the associated gas is separated from the oil. This gas was not used in the past, but was simply burned. It is currently being captured and used as a fuel and valuable chemical feedstock. The possibilities of using associated gases are even wider than those of natural gas. their composition is richer. Associated gases contain less methane than natural gas, but they contain significantly more methane homologues. In order to use associated gas more rationally, it is divided into mixtures of a narrower composition. After separation, gas gasoline, propane and butane, dry gas are obtained. Individual hydrocarbons are also extracted - ethane, propane, butane and others. By dehydrogenating them, unsaturated hydrocarbons are obtained - ethylene, propylene, butylene, etc.

Oil and oil products, their application

Oil is an oily liquid with a pungent odor. It is found in many places on the globe, impregnating porous rocks at various depths.
According to most scientists, oil is the geochemically altered remains of plants and animals that once inhabited the globe. This theory of the organic origin of oil is supported by the fact that oil contains some nitrogenous substances - the breakdown products of substances present in plant tissues. There are also theories about the inorganic origin of oil: its formation as a result of the action of water in the strata of the globe on hot metal carbides (compounds of metals with carbon), followed by a change in the resulting hydrocarbons under the influence of high temperature, high pressure, exposure to metals, air, hydrogen, etc.
When oil is extracted from oil-bearing strata, which sometimes lie in the earth's crust at a depth of several kilometers, oil either comes to the surface under the pressure of gases located on it, or is pumped out by pumps.

The oil industry today is a large national economic complex that lives and develops according to its own laws. What does oil mean today for the national economy of the country? Oil is a raw material for petrochemistry in the production of synthetic rubber, alcohols, polyethylene, polypropylene, a wide range of various plastics and finished products from them, artificial fabrics; a source for the production of motor fuels (gasoline, kerosene, diesel and jet fuels), oils and lubricants, as well as boiler and furnace fuel (fuel oil), building materials (bitumen, tar, asphalt); raw material for obtaining a number of protein preparations used as additives in livestock feed to stimulate its growth.
Oil is our national wealth, the source of the country's power, the foundation of its economy. The oil complex of Russia includes 148 thousand oil wells, 48.3 thousand km of main oil pipelines, 28 oil refineries with a total capacity of more than 300 million tons of oil per year, as well as a large number of other production facilities.
About 900 thousand people are employed at the enterprises of the oil industry and its service industries, including about 20 thousand people in the field of science and scientific services.
Over the past decades, fundamental changes have taken place in the structure of the fuel industry associated with a decrease in the share of the coal industry and the growth of oil and gas extraction and processing industries. If in 1940 they amounted to 20.5%, then in 1984 - 75.3% of the total production of mineral fuel. Now natural gas and open pit coal are coming to the fore. The consumption of oil for energy purposes will be reduced, on the contrary, its use as a chemical raw material will expand. Currently, in the structure of the fuel and energy balance, oil and gas account for 74%, while the share of oil is declining, while the share of gas is growing and is approximately 41%. The share of coal is 20%, the remaining 6% is electricity.
Oil refining was first started by the Dubinin brothers in the Caucasus. Primary oil refining consists in its distillation. Distillation is carried out at refineries after the separation of petroleum gases.

A variety of products of great practical importance are isolated from oil. First, dissolved gaseous hydrocarbons (mainly methane) are removed from it. After distillation of volatile hydrocarbons, the oil is heated. Hydrocarbons with a small number of carbon atoms in the molecule, which have a relatively low boiling point, are the first to go into a vapor state and are distilled off. As the temperature of the mixture rises, hydrocarbons with a higher boiling point are distilled. In this way, individual mixtures (fractions) of oil can be collected. Most often, with such a distillation, four volatile fractions are obtained, which are then subjected to further separation.
The main oil fractions are as follows.
Gasoline fraction, collected from 40 to 200 ° C, contains hydrocarbons from C 5 H 12 to C 11 H 24. Upon further distillation of the isolated fraction, gasoline (t kip = 40–70 °C), petrol
(t kip \u003d 70–120 ° С) - aviation, automobile, etc.
Naphtha fraction, collected in the range from 150 to 250 ° C, contains hydrocarbons from C 8 H 18 to C 14 H 30. Naphtha is used as fuel for tractors. Large quantities of naphtha are processed into gasoline.
Kerosene fraction includes hydrocarbons from C 12 H 26 to C 18 H 38 with a boiling point of 180 to 300 °C. Kerosene, after being refined, is used as a fuel for tractors, jet planes and rockets.
Gas oil fraction (t bale > 275 °C), otherwise called diesel fuel.
Residue after distillation of oil - fuel oil- contains hydrocarbons with a large number of carbon atoms (up to many tens) in the molecule. The fuel oil is also fractionated by reduced pressure distillation to avoid decomposition. As a result, get solar oils(diesel fuel), lubricating oils(autotractor, aviation, industrial, etc.), petrolatum(technical petroleum jelly is used to lubricate metal products in order to protect them from corrosion, purified petroleum jelly is used as a basis for cosmetics and in medicine). From some types of oil paraffin(for the production of matches, candles, etc.). After distillation of volatile components from fuel oil remains tar. It is widely used in road construction. In addition to processing into lubricating oils, fuel oil is also used as a liquid fuel in boiler plants. Gasoline obtained during the distillation of oil is not enough to cover all needs. In the best case, up to 20% of gasoline can be obtained from oil, the rest is high-boiling products. In this regard, chemistry faced the task of finding ways to obtain gasoline in large quantities. A convenient way was found with the help of the theory of the structure of organic compounds created by A.M. Butlerov. High-boiling oil distillation products are unsuitable for use as a motor fuel. Their high boiling point is due to the fact that the molecules of such hydrocarbons are too long chains. If large molecules containing up to 18 carbon atoms are broken down, low-boiling products such as gasoline are obtained. This way was followed by the Russian engineer V.G. Shukhov, who in 1891 developed a method for the splitting of complex hydrocarbons, later called cracking (which means splitting).

The fundamental improvement of cracking was the introduction of the catalytic cracking process into practice. This process was first carried out in 1918 by N.D. Zelinsky. Catalytic cracking made it possible to obtain aviation gasoline on a large scale. In catalytic cracking units at a temperature of 450 °C, under the action of catalysts, long carbon chains are split.

Thermal and catalytic cracking

The main way of processing oil fractions are various types of cracking. For the first time (1871–1878), oil cracking was carried out on a laboratory and semi-industrial scale by A.A. Letniy, an employee of the St. Petersburg Technological Institute. The first patent for a cracking plant was filed by Shukhov in 1891. Cracking has become widespread in industry since the 1920s.
Cracking is the thermal decomposition of hydrocarbons and other constituents of oil. The higher the temperature, the greater the cracking rate and the greater the yield of gases and aromatics.
Cracking of oil fractions, in addition to liquid products, produces a raw material of paramount importance - gases containing unsaturated hydrocarbons (olefins).
There are the following main types of cracking:
liquid phase (20–60 atm, 430–550 °C), gives unsaturated and saturated gasoline, gasoline yield is about 50%, gases 10%;
headspace(normal or reduced pressure, 600 °C), gives unsaturated aromatic gasoline, the yield is less than with liquid-phase cracking, a large amount of gases is formed;
pyrolysis oil (normal or reduced pressure, 650–700 °C), gives a mixture of aromatic hydrocarbons (pyrobenzene), a yield of about 15%, more than half of the raw material is converted into gases;
destructive hydrogenation (hydrogen pressure 200–250 atm, 300–400 °C in the presence of catalysts - iron, nickel, tungsten, etc.), gives marginal gasoline with a yield of up to 90%;
catalytic cracking (300–500 °C in the presence of catalysts - AlCl 3 , aluminosilicates, MoS 3 , Cr 2 O 3 , etc.), gives gaseous products and high-grade gasoline with a predominance of aromatic and saturated hydrocarbons of isostructure.
In technology, the so-called catalytic reforming– conversion of low-grade gasolines into high-grade high-octane gasolines or aromatic hydrocarbons.
The main reactions during cracking are the reactions of splitting hydrocarbon chains, isomerization and cyclization. Free hydrocarbon radicals play a huge role in these processes.

Coke production
and the problem of obtaining liquid fuel

Stocks hard coal in nature far exceed oil reserves. Therefore, coal is the most important type of raw material for the chemical industry.
Currently, industry uses several ways of coal processing: dry distillation (coking, semi-coking), hydrogenation, incomplete combustion, and calcium carbide production.

Dry distillation of coal is used to obtain coke in metallurgy or domestic gas. When coking coal, coke, coal tar, tar water and coking gases are obtained.
Coal tar contains a wide variety of aromatic and other organic compounds. It is separated into several fractions by distillation at normal pressure. Aromatic hydrocarbons, phenols, etc. are obtained from coal tar.
coking gases contain mainly methane, ethylene, hydrogen and carbon monoxide (II). Some are burned, some are recycled.
Hydrogenation of coal is carried out at 400–600 °C under a hydrogen pressure of up to 250 atm in the presence of a catalyst, iron oxides. This produces a liquid mixture of hydrocarbons, which are usually subjected to hydrogenation on Nickel or other catalysts. Low-grade brown coals can be hydrogenated.

Calcium carbide CaC 2 is obtained from coal (coke, anthracite) and lime. Later it is converted into acetylene, which is used in the chemical industry of all countries on an ever-increasing scale.

From the history of the development of OJSC Rosneft-KNOS

The history of the development of the plant is closely connected with the oil and gas industry of the Kuban.
The beginning of oil production in our country is a distant past. Back in the X century. Azerbaijan traded oil with various countries. In the Kuban, industrial oil development began in 1864 in the Maykop region. At the request of the head of the Kuban region, General Karmalin, D.I. Mendeleev in 1880 gave an opinion on the oil content of the Kuban: Ilskaya".
During the years of the first five-year plans, large-scale prospecting work was carried out and commercial oil production began. Associated petroleum gas was partially used as household fuel in workers' settlements, and most of this valuable product was flared. In order to put an end to the wastefulness of natural resources, the USSR Ministry of the Oil Industry in 1952 decided to build a gas and gasoline plant in the village of Afipsky.
During 1963, an act was signed for the commissioning of the first stage of the Afipsky gas and gasoline plant.
At the beginning of 1964, the processing of gas condensates from the Krasnodar Territory began with the production of A-66 gasoline and diesel fuel. The raw material was gas from Kanevsky, Berezansky, Leningradsky, Maikopsky and other large fields. Improving production, the staff of the plant mastered the production of B-70 aviation gasoline and A-72 gasoline.
In August 1970, two new technological units for the processing of gas condensate with the production of aromatics (benzene, toluene, xylene) were put into operation: a secondary distillation unit and a catalytic reforming unit. At the same time, treatment facilities with biological wastewater treatment and the commodity and raw material base of the plant were built.
In 1975, a plant for the production of xylenes was put into operation, and in 1978, an import-made toluene demethylation plant was put into operation. The plant has become one of the leaders in the Minnefteprom for the production of aromatic hydrocarbons for the chemical industry.
In order to improve the management structure of the enterprise and the organization of production units, in January 1980, the production association Krasnodarnefteorgsintez was established. The association included three plants: the Krasnodar site (in operation since August 1922), the Tuapse oil refinery (in operation since 1929) and the Afipsky oil refinery (in operation since December 1963).
In December 1993, the enterprise was reorganized, and in May 1994 Krasnodarnefteorgsintez OJSC was renamed into Rosneft-Krasnodarnefteorgsintez OJSC.

The article was prepared with the support of Met S LLC. If you need to get rid of a cast-iron bathtub, sink or other metal trash, then the best solution would be to contact the Met C company. On the website, located at "www.Metalloloms.Ru", you can, without leaving your monitor screen, order the dismantling and removal of scrap metal at a bargain price. The Met S company employs only highly qualified specialists with a long work experience.

Ending to be

Hydrocarbons are of great economic importance, since they serve as the most important type of raw material for obtaining almost all products of the modern industry of organic synthesis and are widely used for energy purposes. They seem to accumulate solar heat and energy, which are released during combustion. Peat, coal, oil shale, oil, natural and associated petroleum gases contain carbon, the combination of which with oxygen during combustion is accompanied by the release of heat.

coal	peat	oil	natural gas
solid	solid	liquid	gas
without smell	without smell	Strong smell	without smell
uniform composition	uniform composition	mixture of substances	mixture of substances
a dark-colored rock with a high content of combustible matter resulting from the burial of accumulations of various plants in the sedimentary strata	accumulation of semi-decomposed plant mass accumulated at the bottom of swamps and overgrown lakes	natural combustible oily liquid, consists of a mixture of liquid and gaseous hydrocarbons	a mixture of gases formed in the bowels of the Earth during the anaerobic decomposition of organic substances, the gas belongs to the group of sedimentary rocks
Calorific value - the number of calories released by burning 1 kg of fuel
7 000 - 9 000	500 - 2 000	10000 - 15000	?

Coal.

Coal has always been a promising raw material for energy and many chemical products.

Since the 19th century, the first major consumer of coal has been transport, then coal began to be used for the production of electricity, metallurgical coke, the production of various products during chemical processing, carbon-graphite structural materials, plastics, rock wax, synthetic, liquid and gaseous high-calorie fuels, high-nitrogen acids for the production of fertilizers.

Coal is a complex mixture of macromolecular compounds, which include the following elements: C, H, N, O, S. Coal, like oil, contains a large amount of various organic substances, as well as inorganic substances, such as, for example, water, ammonia, hydrogen sulfide and of course carbon itself - coal.

Processing of hard coal goes in three main directions: coking, hydrogenation and incomplete combustion. One of the main ways of coal processing is coking– calcination without air access in coke ovens at a temperature of 1000–1200°C. At this temperature, without access to oxygen, coal undergoes the most complex chemical transformations, as a result of which coke and volatile products are formed:

1. coke gas (hydrogen, methane, carbon monoxide and carbon dioxide, impurities of ammonia, nitrogen and other gases);

2. coal tar (several hundred different organic substances, including benzene and its homologues, phenol and aromatic alcohols, naphthalene and various heterocyclic compounds);

3. supra-tar, or ammonia, water (dissolved ammonia, as well as phenol, hydrogen sulfide and other substances);

4. coke (solid residue of coking, practically pure carbon).

The cooled coke is sent to metallurgical plants.

When the volatile products (coke oven gas) are cooled, coal tar and ammonia water condense.

Passing uncondensed products (ammonia, benzene, hydrogen, methane, CO 2 , nitrogen, ethylene, etc.) through a solution of sulfuric acid, ammonium sulfate is isolated, which is used as a mineral fertilizer. Benzene is taken up in the solvent and distilled off from the solution. After that, coke gas is used as a fuel or as a chemical raw material. Coal tar is obtained in small quantities (3%). But, given the scale of production, coal tar is considered as a raw material for obtaining a number of organic substances. If products boiling up to 350 ° C are driven away from the resin, then a solid mass remains - pitch. It is used for the manufacture of varnishes.

Hydrogenation of coal is carried out at a temperature of 400–600°C under a hydrogen pressure of up to 25 MPa in the presence of a catalyst. In this case, a mixture of liquid hydrocarbons is formed, which can be used as a motor fuel. Obtaining liquid fuel from coal. Liquid synthetic fuels are high-octane gasoline, diesel and boiler fuels. To obtain liquid fuel from coal, it is necessary to increase its hydrogen content by hydrogenation. Hydrogenation is carried out using multiple circulation, which allows you to turn into a liquid and gases the entire organic mass of coal. The advantage of this method is the possibility of hydrogenation of low-grade brown coal.

Coal gasification will make it possible to use low-quality brown and black coals at thermal power plants without polluting the environment with sulfur compounds. This is the only method for obtaining concentrated carbon monoxide (carbon monoxide) CO. Incomplete combustion of coal produces carbon monoxide (II). On a catalyst (nickel, cobalt) at normal or elevated pressure, hydrogen and CO can be used to produce gasoline containing saturated and unsaturated hydrocarbons:

nCO + (2n+1)H 2 → C n H 2n+2 + nH 2 O;

nCO + 2nH 2 → C n H 2n + nH 2 O.

If dry distillation of coal is carried out at 500–550°C, then tar is obtained, which, along with bitumen, is used in the construction industry as a binder in the manufacture of roofing, waterproofing coatings (roofing felt, roofing felt, etc.).

In nature, coal is found in the following regions: the Moscow region, the South Yakutsk basin, the Kuzbass, the Donbass, the Pechora basin, the Tunguska basin, the Lena basin.

Natural gas.

Natural gas is a mixture of gases, the main component of which is methane CH 4 (from 75 to 98% depending on the field), the rest is ethane, propane, butane and a small amount of impurities - nitrogen, carbon monoxide (IV), hydrogen sulfide and vapors water, and, almost always, hydrogen sulfide and organic compounds of oil - mercaptans. It is they who give the gas a specific unpleasant odor, and when burned, they lead to the formation of toxic sulfur dioxide SO 2.

Generally, the higher the molecular weight of the hydrocarbon, the less of it is contained in natural gas. The composition of natural gas from different fields is not the same. Its average composition as a percentage by volume is as follows:

CH 4	C 2 H 6	C 3 H 8	C 4 H 10	N 2 and other gases
75-98	0,5 - 4	0,2 – 1,5	0,1 – 1	1-12

Methane is formed during anaerobic (without air access) fermentation of plant and animal residues, therefore it is formed in bottom sediments and is called "marsh" gas.

Methane deposits in hydrated crystalline form, the so-called methane hydrate, found under a layer of permafrost and at great depths of the oceans. At low temperatures (−800ºC) and high pressures, methane molecules are located in the voids of the crystal lattice of water ice. In the ice voids of one cubic meter of methane hydrate, 164 cubic meters of gas are "mothballed".

Pieces of methane hydrate look like dirty ice, but in air they burn with a yellow-blue flame. An estimated 10,000 to 15,000 gigatonnes of carbon are stored on the planet in the form of methane hydrate (a giga is 1 billion). Such volumes are many times greater than all currently known reserves of natural gas.

Natural gas is a renewable natural resource, as it is continuously synthesized in nature. It is also called "biogas". Therefore, many environmental scientists today associate the prospects for the prosperous existence of mankind precisely with the use of gas as an alternative fuel.

As a fuel, natural gas has great advantages over solid and liquid fuels. Its calorific value is much higher, when burned, it does not leave ash, the combustion products are much more environmentally friendly. Therefore, about 90% of the total volume of produced natural gas is burned as fuel at thermal power plants and boiler houses, in thermal processes at industrial enterprises and in everyday life. About 10% of natural gas is used as a valuable raw material for the chemical industry: to produce hydrogen, acetylene, soot, various plastics, and medicines. Methane, ethane, propane and butane are isolated from natural gas. Products that can be obtained from methane are of great industrial importance. Methane is used for the synthesis of many organic substances - synthesis gas and further synthesis of alcohols based on it; solvents (carbon tetrachloride, methylene chloride, etc.); formaldehyde; acetylene and soot.

Natural gas forms independent deposits. The main deposits of natural combustible gases are located in Northern and Western Siberia, the Volga-Ural basin, the North Caucasus (Stavropol), the Komi Republic, the Astrakhan region, the Barents Sea.