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, decomposition occurs organic matter coal with the formation of 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 is 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.

Production of hydrocarbons from oil

Oil is one of the main sources of aromatic hydrocarbons. Most oils contain only very small amounts 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.


  • Receipt aromatic hydrocarbons. Natural sources
    Receipt hydrocarbons from oil. Oil is one of the main sources aromatic hydrocarbons.


  • Receipt aromatic hydrocarbons. Natural sources. Dry distillation of coal. aromatic hydrocarbons obtained mainly from Nomenclature and isomerism aromatic hydrocarbons.


  • Receipt aromatic hydrocarbons. Natural sources. Dry distillation of coal. aromatic hydrocarbons obtained mainly from


  • Receipt aromatic hydrocarbons. Natural sources.
    1. Synthesis from aromatic hydrocarbons and halo-derivatives of the fatty series in the presence of catalysis ... more ».


  • To the group aromatic compounds included a number of substances, received from natural resins, balms and essential oils.
    Rational names aromatic hydrocarbons usually produced from the name. aromatic hydrocarbons.


  • Natural sources marginal hydrocarbons. Gaseous, liquid and solid substances are widely distributed in nature. hydrocarbons, in most cases occurring not in the form of pure compounds, but in the form of various, sometimes very complex mixtures.


  • isomerism, natural sources and ways receiving olefins. The isomerism of olefins depends on the isomerism of the carbon chain, i.e., on whether the chain is n. Unsaturated (unsaturated) hydrocarbons.


  • hydrocarbons. Carbohydrates are widely distributed in nature and play a very important role in human life. They are part of the food, and usually a person's need for energy is covered when eating for the most part precisely at the expense of carbohydrates.


  • The H2C=CH- radical derived from ethylene is usually called vinyl; the H2C=CH-CH2- radical derived from propylene is called allyl. Natural sources and ways receiving olefins.


  • Natural sources marginal hydrocarbons there are also some products of the dry distillation of wood, peat, brown and black coal, oil shale. Synthetic ways receiving marginal hydrocarbons.

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During the lesson, you will be able to explore the topic " natural springs hydrocarbons. Oil refining". More than 90% of all energy consumed by mankind today is extracted from natural fossils. organic compounds. You will learn about natural resources ( natural gas, oil, coal), about what happens to oil after it is extracted.

Topic: Limit hydrocarbons

Lesson: Natural Sources of Hydrocarbons

About 90% of the energy consumed by modern civilization is generated by burning natural fossil fuels - natural gas, oil and coal.

Russia is a country rich in natural fossil fuels. There are large reserves of oil and natural gas in Western Siberia and the Urals. Hard coal is mined in the Kuznetsk, South Yakutsk basins and other regions.

Natural gas consists on average of 95% by volume of methane.

In addition to methane, natural gas from various fields contains nitrogen, carbon dioxide, helium, hydrogen sulfide, and other light alkanes - ethane, propane and butanes.

Natural gas is extracted from underground deposits, where it is under high pressure. Methane and other hydrocarbons are formed from organic substances of plant and animal origin during their decomposition without air access. Methane is produced constantly and currently as a result of the activity of microorganisms.

Methane found on planets solar system and their companions.

Pure methane is odorless. However, the gas used in everyday life has a characteristic unpleasant odor. This is the smell of special additives - mercaptans. The smell of mercaptans allows you to detect a leak of domestic gas in time. Mixtures of methane with air are explosive in a wide range of ratios - from 5 to 15% of gas by volume. Therefore, if you smell gas in the room, you can not only light a fire, but also use electrical switches. The smallest spark can cause an explosion.

Rice. 1. Oil from different fields

Oil- a thick liquid like oil. Its color is from light yellow to brown and black.

Rice. 2. Oil fields

Oil from different fields varies greatly in composition. Rice. 1. The main part of oil is hydrocarbons containing 5 or more carbon atoms. Basically, these hydrocarbons are saturated, i.e. alkanes. Rice. 2.

The composition of oil also includes organic compounds containing sulfur, oxygen, nitrogen. Oil contains water and inorganic impurities.

Gases are dissolved in oil, which are released during its extraction - associated petroleum gases. These are methane, ethane, propane, butanes with impurities of nitrogen, carbon dioxide and hydrogen sulfide.

Coal, like oil, is a complex mixture. The share of carbon in it accounts for 80-90%. The rest is hydrogen, oxygen, sulfur, nitrogen and some other elements. In brown coal the proportion of carbon and organic matter is lower than in stone. Even less organic oil shale.

In industry, coal is heated to 900-1100 0 C without air. This process is called coking. The result is coke with a high carbon content, coke gas and coal tar, necessary for metallurgy. A lot of organic substances are released from the gas and tar. Rice. 3.

Rice. 3. The device of the coke oven

Natural gas and oil are the most important sources of raw materials for chemical industry. Oil as it is produced, or "crude oil", is difficult to use even as a fuel. Therefore, crude oil is divided into fractions (from the English "fraction" - "part"), using differences in the boiling points of its constituent substances.

Oil separation method based on different temperatures boiling of its constituent hydrocarbons is called distillation or distillation. Rice. 4.

Rice. 4. Products of oil refining

The fraction that is distilled from about 50 to 180 0 C is called gasoline.

Kerosene boils at temperatures of 180-300 0 C.

A thick black residue that does not contain volatile substances is called fuel oil.

There are also a number of intermediate fractions boiling in narrower ranges - petroleum ethers (40-70 0 C and 70-100 0 C), white spirit (149-204 ° C), and gas oil (200-500 0 C). They are used as solvents. Fuel oil can be distilled under reduced pressure, in this way lubricating oils and paraffin are obtained from it. Solid residue from the distillation of fuel oil - asphalt. It is used for the production of road surfaces.

Processing of associated petroleum gases is a separate industry and makes it possible to obtain a number of valuable products.

Summing up the lesson

During the lesson, you studied the topic “Natural sources of hydrocarbons. Oil refining". More than 90% of all energy currently consumed by mankind is extracted from fossil natural organic compounds. You learned about natural resources (natural gas, oil, coal), about what happens to oil after it is extracted.

Bibliography

1. Rudzitis G.E. Chemistry. Fundamentals of General Chemistry. Grade 10: textbook for educational institutions: a basic level of/ G. E. Rudzitis, F.G. Feldman. - 14th edition. - M.: Education, 2012.

2. Chemistry. Grade 10. Profile level: studies. for general education institutions / V.V. Eremin, N.E. Kuzmenko, V.V. Lunin and others - M.: Drofa, 2008. - 463 p.

3. Chemistry. Grade 11. Profile level: textbook. for general education institutions / V.V. Eremin, N.E. Kuzmenko, V.V. Lunin and others - M.: Drofa, 2010. - 462 p.

4. Khomchenko G.P., Khomchenko I.G. Collection of problems in chemistry for those entering the universities. - 4th ed. - M.: RIA "New Wave": Publisher Umerenkov, 2012. - 278 p.

Homework

1. Nos. 3, 6 (p. 74) Rudzitis G.E., Feldman F.G. Chemistry: Organic Chemistry. Grade 10: textbook for educational institutions: basic level / G. E. Rudzitis, F.G. Feldman. - 14th edition. - M.: Education, 2012.

2. What is the difference between associated petroleum gas and natural gas?

3. How is oil refining carried out?

It should be noted that hydrocarbons are widely distributed in nature. Most organic matter comes from natural sources. In the process of synthesis of organic compounds, natural and associated gases, coal and brown coal, oil, peat, products of animal and vegetable origin are used as raw materials.

Natural sources of hydrocarbons: natural gases.

Natural gases are natural mixtures of hydrocarbons of various structures and some gas impurities (hydrogen sulfide, hydrogen, carbon dioxide) that fill rocks in earth's crust. These compounds are formed as a result of hydrolysis of organic substances at great depths in the Earth's thickness. They are found in the free state in the form of huge accumulations - gas, gas condensate and oil and gas fields.

Main structural component combustible natural gases are CH₄ (methane - 98%), С₂Н₆ (ethane - 4.5%), propane (С₃Н₈ - 1.7%), butane (С₄Н₁₀ - 0.8%), pentane (С₅Н₁₂ - 0.6% ). Associated petroleum gas is part of the oil in a dissolved state and is released from it due to a decrease in pressure when the oil rises to the surface. In gas and oil fields, one ton of oil contains from 30 to 300 sq. m of gas. Natural sources of hydrocarbons are a valuable fuel and raw material for the organic synthesis industry. Gas is supplied to gas processing enterprises, where it can be processed (oil, low-temperature adsorption, condensation and rectification). It is divided into separate components, each of which is used for specific purposes. For example, from methane synthesis gas, which are the basic raw materials for the production of other hydrocarbons, acetylene, methanol, methanal, chloroform.

Natural sources of hydrocarbons: oil.

Oil is a complex mixture that consists mainly of naphthenic, paraffinic and aromatic hydrocarbons. The composition of oil includes asphalt-resinous substances, mono- and disulfides, mercaptans, thiophene, thiophane, hydrogen sulfide, piperidine, pyridine and its homologues, as well as other substances. Based on the products, more than 3,000 different products are obtained using petrochemical synthesis methods, incl. ethylene, benzene, propylene, dichloroethane, vinyl chloride, styrene, ethanol, isopropanol, butylenes, various plastics, chemical fibers, dyes, detergents, drugs, explosives, etc.

Peat is a sedimentary rock of plant origin. This substance is used as a fuel (mainly for thermal power plants), chemical raw materials (for the synthesis of many organic substances), antiseptic bedding on farms, especially in poultry farms, and a component of fertilizers for gardening and field crops.

Natural sources of hydrocarbons: xylem or wood.

Xylem - tissue higher plants, along which water and dissolved nutrients come from the rhizome of the system to the leaves, as well as other organs of the plant. It consists of cells with a stiff shell, which have a vascular conduction system. Depending on the type of wood, it contains different amount pectins and mineral compounds (mainly calcium salts), lipids and essential oils. Wood is used as a fuel; methyl alcohol, acetic acid, cellulose, and other substances can be synthesized from it. From some types of wood, dyes are obtained (sandalwood, logwood), tannins (oak), resins and balsams (cedar, pine, spruce), alkaloids (plants of the nightshade, poppy, ranunculus, umbrella families). Some alkaloids are used as medicines(chitin, caffeine), herbicides (Anabasin), insecticides (nicotine).

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 the microscopic marine plants and animals that were

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. IN

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 the 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 Lately thanks to technical advances becomes 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 chemical substances containing 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

IN late XIX V. 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 there is an urgent need 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 engine internal combustion operating 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 also 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

– consists (mainly) of methane and (in smaller quantities) of its closest homologues - ethane, propane, butane, pentane, hexane, etc.; observed in associated petroleum gas, i.e., natural gas that is in nature above oil or dissolved in it under pressure.

Oil

- it is an oily combustible liquid, consisting of alkanes, cycloalkanes, arenes (predominate), as well as oxygen-, nitrogen- and sulfur-containing compounds.

Coal

- solid combustible mineral organic origin. It contains little graphite a and many complex cyclic compounds, including the elements C, H, O, N and S. There are anthracite (almost anhydrous), coal (-4% moisture) and brown coal (50-60% moisture). By coking coal is converted into hydrocarbons (gaseous, liquid and solid) and coke (rather pure graphite).

Coal coking

Heating coal without air access to 900-1050 ° C leads to its thermal decomposition with the formation of volatile products (coal tar, ammonia water and coke oven gas) and a solid residue - coke.

Main products: coke - 96-98% carbon; coke oven gas - 60% hydrogen, 25% methane, 7% carbon monoxide (II), etc.

By-products: coal tar (benzene, toluene), ammonia (from coke oven gas), etc.

Oil refining by rectification method

The pre-purified oil is subjected to atmospheric (or vacuum) distillation into fractions with certain boiling point ranges in continuous distillation columns.

Main products: light and heavy gasoline, kerosene, gas oil, lubricating oils, fuel oil, tar.

Oil refining by catalytic cracking

Raw materials: high-boiling oil fractions (kerosene, gas oil, etc.)

Auxiliary materials: catalysts (modified aluminosilicates).

The main chemical process: at a temperature of 500-600 ° C and a pressure of 5 10 5 Pa, hydrocarbon molecules are split into smaller molecules, catalytic cracking is accompanied by aromatization, isomerization, alkylation reactions.

Products: mixture of low-boiling hydrocarbons (fuel, feedstock for petrochemicals).

C 16. H 34 → C 8 H 18 + C 8 H 16
C 8 H 18 → C 4 H 10 + C 4 H 8
C 4 H 10 → C 2 H 6 + C 2 H 4