Who discovered methane. Molecular and structural formula of methane

Methane is the simplest representative of saturated hydrocarbons. It burns well and releases a large amount of heat, so it is widely used by industry.

How to obtain methane in industry

Methane is part of natural gas and gas accompanying oil fields. Therefore, industry obtains methane from these gases.

How to get methane at home

Methane also has another name – swamp gas. In order to get it at home, you should take a little soil from the bottom of the swamp and place it in a jar, pouring water on top. The jar is tightly sealed and placed in a dark and warm place. After a few days, you will notice the appearance of small gas bubbles on the surface of the water. The resulting methane can be removed from the can through a gas outlet tube.

How to obtain methane in laboratory conditions

There are several ways to obtain methane in a laboratory:

Passing a mixture of hydrogen sulfide and carbon disulfide through a tube at the bottom of which there is hot copper: CS 2 + 2H 2 S + 8Cu = CH 4 + Cu 2 S. This was the very first method of producing methane. Later it was found that methane can be obtained by heating a mixture of hydrogen and carbon in the presence of a nickel catalyst to 475 degrees. Without using a catalyst, the mixture has to be heated to 1200 degrees. C + 2H2 = CH4
Currently, methane is produced by heating a mixture of sodium hydroxide and sodium acetate: CH 3 COONa + NaOH = Na 2 CO 3 + CH 4.
Pure methane can be obtained by the reaction of aluminum carbide and water: Al 4 C 3 + 12H 2 O = 4 Al(OH) 3 + 3CH 4
Methane synthesis can also be carried out on the basis of a combination of hydrogen and carbon monoxide: CO + 3H 2 = CH 4 + H 2 O

How to get acetylene from methane

Acetylene can be obtained from methane by heating the latter to a temperature of one and a half thousand degrees:

2 CH 4 >C 2 H 2 + H 2

How to get methanol from methane

To obtain methanol from methane, several chemical reactions must be carried out. First, a reaction occurs between chlorine and methane. This reaction occurs only in the light, because it is triggered by photons of light. During this reaction, trichloromethane and hydrochloric acid are formed: CH 4 + Cl 2 > CH 3 Cl + HCl. Then a reaction is carried out between the resulting trichloromethane and an aqueous solution of sodium hydroxide. The result is methanol and sodium chloride: CH 3 Cl + NaOH > NaCl + CH 3 OH

How to obtain aniline from methane

It is possible to obtain aniline from methane by only performing a whole chain of reactions, which schematically looks like this: CH 4 > C 2 H 2 > C 6 H 6 > C 6 H 5 NO 2 > C 6 H 5 NH 2 .

First, methane is heated to 1500 degrees, resulting in the formation of acetylene. Benzene is then obtained from acetylene using the Zelinsky reaction. To do this, acetylene is passed through a tube heated to 600 degrees, half filled with activated carbon: 3C 2 H 2 = C 6 H 6

Nitrobenzene is obtained from benzene: C 6 H 6 + HNO 3 = C 6 H 5 NO 2 + H 2 O, which is the feedstock for the production of aniline. This process follows Zinin’s reaction:

C 6 H 5 NO 2 + 3(NH 4) 2 S = C 6 H 5 NH 2 + 6NH 3 + 3S + 2H 2 O.

Methane is an organic gas, odorless and colorless. CH 4 is its chemical formula, and the mass of the substance is less than the mass of air. Dissolution in water proceeds slowly. Speaking about the organic nature of methane, it means that almost 95% of cases of its occurrence are of a natural nature. For example, it is released during the decomposition of plant debris. Therefore, it is not surprising that many of its characteristics were studied even before the New Era, when people observed air bubbles on the surface of stagnant bodies of water. These bubbles were precisely methane released during the decay of plants at the bottom of the swamp.

Other natural sources of gas include:

Livestock. Bacteria living in their stomachs emit methane during their life processes, and its share accounts for 20% of all atmospheric gas.
Plants. Methane is an integral substance released during photosynthesis.
Insects. Termites are the most active methane emitters.
Mines. Under the earth's surface, the slow decomposition of coal constantly occurs, during which methane is formed.
Oil wells. The content of this gas in oil is simply enormous.
Volcanoes. Probably, methane is also formed there due to the fact that prehistoric organic matter is actively decomposing.
Ocean. Deep underwater there are cracks through which methane can leak.
Forest burning.
Industry. Despite the apparent activity of these enterprises, their share of emissions in the total mass is negligible.

All of the above examples clearly confirm the fact that methane was constantly in the atmosphere, its appearance is not associated with the beginning of active human activity. That is why the presence of methane on a planet is a sign that there may be life on it or that it once was there.

However, the “naturalness” of this gas does not mean that it does not cause us any harm. Its vapors, especially at elevated concentrations, are quite capable of leading to human death. In the early stages of the development of the mining industry, explosions or severe poisoning of miners with methane were often recorded. If you follow information in the media, these events also take place in the modern world. To minimize the likelihood of methane poisoning, it is necessary, at the first sign of it, to place an order for a professional analysis of the air in the room, with the help of which it will be possible to accurately determine the concentration.

Methane in the modern world

Gas is widely used in the modern world:

Internal combustion engines quite often operate on methane.
Gas makes it possible to produce many medications, including antiseptics and sleeping pills.
Methane is the basis of formaldehyde and methanol, with which fertilizers and many other substances are made.
Without methane it is impossible to make fire extinguishers and solvents.
Hydrocyanic acid is not just a poison, it also has wide practical applications, and its production process is based on the oxidation of a methane and ammonia mixture.

Methane and its danger to the human body

The danger of methane lies in the following factors:

Explosion hazard. It was this property that gave it the name “explosive gas.” An accumulation of methane, the smallest spark - all this can lead to a destructive explosion. That is why in places where accumulations or emissions of this gas are recorded, you should not smoke or use open flame sources. But sometimes even these safety measures are not enough; gas continues to take human lives.
We have already mentioned the property according to which methane can accumulate in mines. It is mainly found in the voids between large rock layers, as well as voids created by miners during the mining process. The more active the mining, the more intense the methane emissions, and therefore it is the mine workers who most often die from this gas.
Explosions are not the only danger; methane can also cause severe poisoning. Inhaling large volumes of it leads to a lack of oxygen in the blood, “ringing” in the ears, and a feeling of a “cast iron” head. Increased concentration causes the heart to beat faster, the person feels general weakness, suffers from nausea, and the skin may turn red. The most serious consequences are fainting, pallor, convulsions and even death.
Unfortunately, methane in its pure form has no odor and is therefore difficult to detect. The “methane” aroma that we can smell is the result of special fragrances that make its use safer and more controlled.
In the mines, of course, no fragrances are added to the methane. Since ancient times, people have been using special methods to detect its presence in the air. The first miners, for example, took a canary with them. If the bird stops singing or even dies, then it is necessary to urgently remove itself from the slaughter.
In the 50s of the last century, they began to use special devices that made it possible to accurately determine the percentage of methane in the air mixture. However, experienced workers said that the canary is an even better method than newfangled devices. Of course, modern devices are more sensitive and compact; sometimes they are mounted directly into miners’ helmets, just like lamps. Stationary sensors are also installed in mines, constantly transmitting information to specialists. Dangerous increases force immediate power cuts and staff evacuations. Nowadays, special installations are also used that can localize the detonation of coal dust at the earliest stages. Before the work shift begins, the amount of methane in the mine is reduced to extremely safe levels.

It turns out that the danger of methane for humans comes from two sides at once. The tendency to detonate, the poisonous effect, the absence of odor and color - all this makes “explosive gas” incredibly dangerous. In order not to encounter its worst sides, it is worth ordering an environmental assessment in advance that can determine the level of methane concentration in the air.

The molecular, structural and electronic formula of methane are compiled on the basis of Butlerov’s theory of the structure of organic substances. Before we begin writing such formulas, let's start with a brief description of this hydrocarbon.

Features of methane

This substance is explosive; it is also called “swamp” gas. The specific smell of this saturated hydrocarbon is known to everyone. During the combustion process, there are no chemical components left from it that have a negative effect on the human body. Methane is an active participant in the formation of the greenhouse effect.

Physical properties

The first representative of the homologous series of alkanes was discovered by scientists in the atmosphere of Titan and Mars. Considering the fact that methane is associated with the existence of living organisms, a hypothesis has emerged about the existence of life on these planets. On Saturn, Jupiter, Neptune, and Uranus, methane appeared as a product of the chemical processing of substances of inorganic origin. On the surface of our planet its content is insignificant.

general characteristics

Methane has no color, it is almost twice as light as air, and is poorly soluble in water. In the composition of natural gas, its amount reaches 98 percent. It contains from 30 to 90 percent methane. To a large extent, methane is of biological origin.

Ungulate herbivores goats and cows emit quite a significant amount of methane when processing bacteria in their stomachs. Among the important sources of the homologous series of alkanes, we highlight swamps, termites, filtration of natural gas, and the process of plant photosynthesis. If traces of methane are detected on a planet, we can talk about the existence of biological life on it.

Methods of obtaining

The expanded structural formula of methane confirms that its molecule contains only saturated single bonds formed by hybrid clouds. Among the laboratory options for producing this hydrocarbon, we note the fusion of sodium acetate with solid alkali, as well as the interaction of aluminum carbide with water.

Methane burns with a bluish flame, releasing about 39 MJ per cubic meter. This substance forms explosive mixtures with air. The most dangerous is methane, which is released during underground mining of mineral deposits in mountain mines. There is a high risk of methane explosion in coal preparation and briquette factories, as well as in sorting plants.

Physiological action

If the percentage of methane in the air is between 5 and 16 percent, exposure to oxygen can cause the methane to ignite. If there is a significant increase in this chemical in the mixture, the likelihood of an explosion increases.

If the concentration of this alkane in the air is 43 percent, it causes suffocation.

During an explosion, the propagation speed is from 500 to 700 meters per second. After methane comes into contact with a heat source, the process of ignition of the alkane occurs with some delay.

It is on this property that the production of explosion-proof electrical equipment and safety explosive components is based.

Since methane is the most thermally stable, it is widely used in the form of industrial and household fuel, and is also used as a valuable raw material for chemical synthesis. The structural formula of tri-ethylmethane characterizes the structural features of representatives of this class of hydrocarbons.

During its chemical interaction with chlorine when exposed to ultraviolet irradiation, the formation of several reaction products is possible. Depending on the amount of the starting substance, it is possible to obtain chloromethane, chloroform, or carbon tetrachloride during substitution.

In case of incomplete combustion of methane, soot is formed. In the case of catalytic oxidation, formaldehyde is formed. The final product of interaction with sulfur is carbon disulfide.

Features of the structure of methane

What is its structural formula? Methane is a saturated hydrocarbon with the general formula C n H 2n+2. Let us consider the features of the formation of the molecule to explain how the structural formula is formed.

Methane consists of one carbon atom and four hydrogen atoms linked together by a covalent polar chemical bond. Let us explain the structural formulas based on the structure of the carbon atom.

Type of hybridization

The spatial structure of methane is characterized by a tetrahedral structure. Since carbon has four valence electrons at its outer level, when the atom is heated, an electron transitions from the second s orbital to p. As a result, carbon has four unpaired (“free”) electrons at its last energy level. The full structural formula of methane is based on the formation of four hybrid clouds, which are oriented in space at an angle of 109 degrees 28 minutes, forming a tetrahedron structure. Next, the tops of the hybrid clouds overlap with non-hybrid clouds of hydrogen atoms.

The full and abbreviated structural formula of methane fully corresponds to Butlerov’s theory. A simple (single) bond is formed between carbon and hydrogen, therefore addition reactions are not typical for this chemical substance.

The final structural formula is presented below. Methane is the first representative of the class of saturated hydrocarbons; it has the typical properties of a saturated alkane. The structural and electronic formula of methane confirms the type of hybridization of the carbon atom in this organic substance.

From a school chemistry course

This class of hydrocarbons, of which “swamp gas” is a representative, is studied in the 10th grade course in high school. For example, the children are offered the following task: “Write the structural formulas of methane.” It is necessary to understand that for this substance only a detailed structural configuration can be described according to Butlerov’s theory.

Its abbreviated formula will coincide with the molecular one, written as CH4. According to the new federal educational standards, which were introduced in connection with the reorganization of Russian education, in the basic chemistry course, all issues related to the characteristics of classes of organic substances are reviewed.

Industrial synthesis

Based on methane, industrial processes for such an important chemical component as acetylene have been developed. The basis of thermal and electrical cracking was precisely its structural formula. Methane during catalytic oxidation with ammonia forms hydrocyanic acid.

This organic substance is used to produce synthesis gas. When interacting with water vapor, a mixture of carbon monoxide and hydrogen is obtained, which is the raw material for the production of saturated carbonyl compounds.

Of particular importance is the interaction with nitric acid, which results in nitromethane.

Application in the form of automobile fuel

Due to the shortage of natural sources of hydrocarbons, as well as the depletion of the raw material base, the issue related to the search for new (alternative) sources for obtaining fuel is of particular relevance. One of these options is one that contains methane.

Considering the difference in density between gasoline fuel and the first representative of the class of alkanes, there are certain features of its use as an energy source for automobile engines. In order to avoid the need to transport huge amounts of methane, its density is increased by compression (at a pressure of about 250 atmospheres). Methane is stored in a liquefied state in cylinders installed in cars.

Impact on the atmosphere

It was already discussed above that methane has an impact on the greenhouse effect. If the degree of effect of carbon monoxide (4) on the climate is taken conventionally as one, then the share of “swamp gas” in it is 23 units. Over the past two centuries, scientists have observed an increase in the quantitative content of methane in the earth's atmosphere.

Currently, the approximate amount of CH4 is estimated at 1.8 ppm. Despite the fact that this figure is 200 times less than the presence of carbon dioxide, there is a conversation among scientists about the possible risk of retaining the heat emitted by the planet.

Due to the excellent calorific value of “swamp gas”, it is used not only as a feedstock for chemical synthesis, but also as an energy source.

For example, a variety of gas boilers and water heaters designed for individual heating systems in private homes and country cottages operate on methane.

This autonomous heating option is very beneficial for homeowners and is not associated with accidents that systematically occur on centralized heating systems. Thanks to a gas boiler operating on this type of fuel, 15-20 minutes are enough to completely heat a two-story cottage.

Conclusion

Methane, the structural and molecular formulas of which were given above, is a natural source of energy. Due to the fact that it contains only a carbon atom and hydrogen atoms, environmentalists recognize the environmental safety of this saturated hydrocarbon.

Under standard conditions (air temperature 20 degrees Celsius, pressure 101325 Pa) this substance is gaseous, non-toxic, insoluble in water.

When the air temperature drops to -161 degrees, methane is compressed, which is widely used in industry.

Methane affects human health. It is not a poisonous substance, but is considered an asphyxiating gas. There are even maximum standards (maximum concentration limits) for the content of this chemical in the atmosphere.

For example, work in mines is permitted only in cases where its amount does not exceed 300 milligrams per cubic meter. By analyzing the structural features of this organic substance, we can conclude that its chemical and physical properties are similar to all other representatives of the class of saturated (saturated) hydrocarbons.

We analyzed the structural formulas and spatial structure of methane. which begins "swamp gas" has the general molecular formula C n H 2n+2 .

The chemical properties of methane are no different from the properties inherent in all. In a school chemistry course, methane is studied as one of the first organic substances, since it is one of the simplest representatives of alkanes.

Methane formula and methods for its production

Methane is found in large quantities in the atmosphere. We do not pay attention to the presence of this gas in the air, because it does not affect our body in any way, but canaries are very sensitive to methane.

Once upon a time they even helped miners go underground. When the percentage of methane changed, the birds stopped singing. This served as a signal to the person that he had descended too deep and needed to climb up.

Methane is formed as a result of the breakdown of the remains of living organisms. It is no coincidence that methane is translated from English as swamp gas, because it can be found in swampy reservoirs and coal mines.

The main source of gas in the agricultural sector is cattle. Yes, they remove methane from the body along with other waste products. By the way, an increase in the number of cattle on the planet can lead to the destruction of the ozone layer, because methane and oxygen form an explosive mixture.

Methane can be produced industrially by heating carbon and hydrogen or by synthesizing water gas; all reactions occur in the presence of a catalyst, most often nickel.

In the USA, an entire methane extraction system has been developed; it is capable of extracting up to 80% of gas from natural coal. Today, world methane reserves are estimated by experts at 260 trillion cubic meters! Even natural gas reserves are significantly smaller.

In the laboratory, methane is produced by reacting aluminum carbide (an inorganic compound of aluminum with carbon) and water. Also using, which reacts with sodium acetate, better known as food additive E262.

Physical properties of methane

Characteristic:

Colorless gas, odorless.
Explosive.
Insoluble in water.
Boiling point: -162 o C, freezing point: -183°C.
Molar mass: 16.044 g/mol.
Density: 0.656 kg/m³.

Chemical properties of methane

Speaking about chemical properties, we highlight those reactions in which methane enters. They are given below along with the formulas.

Methane combustion

Like all organic substances, methane burns. You can notice that during combustion a bluish flame is formed.

CH 4 + 2O 2 → CO 2 + 2H 2 O

This reaction is called a combustion or complete oxidation reaction.

Substitution

Methane also reacts with halogens. These are chemical elements of group 17 in the periodic table of Mendeleev. These include: fluorine, chlorine, bromine, iodine and astatine. The reaction with halogens is called a substitution or halogenation reaction. This reaction occurs only in the presence of light.

Chlorination and bromination

If chlorine is used as a halogen, the reaction will be called a chlorination reaction. If the halogen is bromine, then bromination, and so on.

CH 4 + Cl 2 → CH 3 Cl + HCl

CH 4 + Br 2 → CH 3 Br + HBr

Chlorination. Lower alkanes can chlorinate completely.

CH 4 + Cl 2 → CH 3 Cl + HCl

CH 3 Cl + Cl 2 → CH 2 Cl 2 + HCl

CH 2 Cl 2 + Cl 2 → CHCl 3 + HCl

CHCl 3 + Cl 2 → CСl 4 + HCl

Likewise, methane can completely undergo bromination reaction.

CH 4 + Br 2 → CH 3 Br + H Br

CH 3 Br + Br 2 → CH 2 Br 2 + HBr

CH 2 Br 2 + Br 2 → CHBr 3 + HBr

CHBr 3 + Br 2 → CBr 4 + HBr

With iodine there is no such reaction, but with fluorine, on the contrary, it is accompanied by a rapid explosion.

Decomposition

This hydrocarbon is also characterized by a decomposition reaction. Full decomposition:

CH 4 → C + 2H₂

And incomplete decomposition:

2CH 4 → C 2 H 2 + 3H 2

Reaction with acids

Methane reacts with concentrated sulfuric acid. The reaction is called sulfonation and occurs with slight heating.

2CH 4 + H 2 SO 4 → CH 3 SO 3 H + H 2 O

Oxidation

As already mentioned, CH 4 can be completely oxidized, but with a lack of oxygen, incomplete oxidation is possible.

2CH 4 + 3O 2 → 2CO + 4H 2 O

CH 4 + O 2 → C + 2H 2 O

Among other things, this gas is characterized by catalytic oxidation. It occurs in the presence of a catalyst. At different ratios of moles of substance, different final reaction products are obtained. Mainly:

alcohols: 2CH 4 + O 2 → 2CO 3 OH
aldehydes: CH 4 + O 2 → HSON + H 2 O
: 2CH 4 + 3O 2 → 2НСООН + 2Н 2 O

The reaction takes place at a temperature of 1500°C. This reaction is also called cracking - thermal decomposition.

Methane nitration

There is also a nitration reaction or the Konovalov reaction, named after the scientist who proved that dilute nitric acid acts with saturated hydrocarbons. The reaction products are called nitro compounds.

CH 4 + HNO 3 → CH 3 NO 2 + H 2 O

The reaction is carried out at a temperature of 140-150°C.

Methane dehydrogenation

In addition, methane is characterized by a dehydrogenation (decomposition) reaction - the detachment of hydrogen atoms and the production of acetylene, in this case.

2CH 4 → C 2 H 2 + 3H 2

Application of methane

Methane, like other saturated hydrocarbons, is widely used in everyday life. It is used in the production of gasoline, aviation and diesel fuel.

Used as a base for the production of various organic raw materials in enterprises. Methane is also widely used in medicine and cosmetology.

Methane is used to produce synthetic rubber, paints and tires.

Athletes use so-called liquid methane to quickly gain weight in a short period of time.

And when methane is chlorinated, a substance is formed that is subsequently used to degrease surfaces or as a component in nail polish removers. For some time, the product of the interaction of methane and chlorine was used as an anesthesia.