Marsh gas: formula and application

The gas that emerges from the bottom of the reservoirs is a marsh gas with an unpleasant odor (another general name is methane). From the point of view of science, this is a form, or hydrogelic methyl. For the most part, it consists of methane (CH ₄ ). It can also contain nitrogen, argon, hydrogen, phosphine and carbon dioxide.

Key Features

The standard composition, chemical formula of marsh gas - all this clearly demonstrates its belonging to the simplest compounds of carbon. Around this item, the remaining components are grouped. Marsh gas is found naturally in the free state as a mixture with carbon dioxide or nitrogen. It occurs as a result of the decomposition of organic substances. As a rule, they are under water and deprived of access to air plants.

Coal - another place where combustible swamp gas is formed. It accumulates among rocks after the decomposition of organic residues. Numerous voids contribute to this. Such gases escape when a randomly generated hole appears.

Places of education

Despite its fairly unambiguous name, marsh gas (or rather, methane) is also released from earth cracks alongside oil fields. The first such cases were recorded in the United States of America on the banks of the Allegheny River, as well as in Russia in the Caspian region. In Baku for this reason, for a long time, there was a legend about the mysterious Baku lights. The natural phenomenon turned out to be mixed with carbon dioxide, nitrogen and oil vapors by swamp gas.

With the development of industry and technology of mining, people have learned to utilize the allocated methane. The first such plant appeared in Pennsylvania. Gas marsh is characterized by the fact that it is formed continuously, it can be found in any marsh or pond. Often it is enough just to touch the silt with a stick. After that, the gas bubbles float to the water surface.

Basis of swamp gas

The formation of the main component of natural gas (methane) is assisted by bacteria. Because of them, the fermentation of plant cellulose, which promotes the appearance of methane, begins. The cleanest methane is believed to be characteristic of the mud volcanoes of the Absheron and Kerch peninsulas.

In addition, it occurs in salt deposits, springs and fumaroles - holes and cracks, located at the foot of volcanoes. Methane is present in the human intestine. It contains the products of the exhalation of some animals. One of the first written evidence of this substance can be considered the works of the ancient writer Pliny, who mentioned gaseous combustible compounds.

Explosion hazard

Most of all, marsh gas is known for its own destructive properties. When ignited in a mixture with air, it causes an explosion. The reason for this is the properties of methane. The explosion of swamp gas and similar compounds for a long time terrified people explaining what happened with superstition. The causes of the anomaly became clear only after a scientific study of this phenomenon.

Swamp gas, methane and other explosive compounds prompted people to invent the Davy lamp. It began to be used both in swamps and in coal mines. In this lamp, the combustion products were removed using a special grid, which eliminated the possibility of igniting a combustible gas mixture.

History of the discovery

A great contribution to the study of swamp gas (methane) was made by the Italian scientist Allesandro Volta. In 1776, he proved that this substance is different from hydrogen, since it needs twice as much oxygen for combustion. In addition, it was Volta who determined that marsh gas is a source of carbonic acid.

The Italian discovered methane on the border of Switzerland and Italy next to Lake Maggiore. The inspiration for the scientist was the article of the American scientist and the policy of Benjamin Franklin about the phenomenon of "combustible air". Volta was the first to receive methane, collecting the gas emitted by the swamp.

Continuation of research

Other important researchers of the natural phenomenon were the French chemist Claude Berthollet and the British chemist William Henry. The last of them in 1805 determined the composition of the swamp gas and distinguished it from ethylene (the so-called oil gas).

The riddle of an explosive substance was hidden in its main component - methane. It was defined as a light hydrocarbon gas (unlike the heavy hydrocarbon gas of ethylene). Over time, another term was established - hydrogen chloride. Henry's research was continued by John Dalton and Jens Jacob Berzelius.

In 1813, an English chemist and geologist, Humphry Davy, conducted an analysis of mine gas and came to the conclusion that this substance is a mixture of methane, carbonic anhydride and nitrogen. So it was proved that the combustible mixture, which is released in the mines, is identical to a similar mixture in the marshes.

Influence on ecology

The characteristic methane for a swamp gas is due to certain chemical reactions. First of all, this is a dry distillation of organic matter (for example, peat or wood). Chemically pure methane is obtained by decomposition of zinc methyl water (zinc oxide is produced). Today, this substance attracts the attention of many ecologists because of their participation in the formation of the greenhouse effect. This is due to the accumulation of methane in the Earth's atmosphere. The swamp gas absorbs thermal radiation in the infrared region of the spectrum. By this parameter, it is second only to pure carbon dioxide. Environmentalists estimate the contribution of methane to the increase in the greenhouse effect in about 30%.

The properties, composition, chemical formula of marsh gas are now being studied as part of a study of its effect on the atmosphere of our planet. In natural quantities produced by nature itself, it was not dangerous as a cause of the greenhouse effect. However, the problem is that a huge amount of methane enters the atmosphere through the fault of the people themselves. Analog of swamp gas is produced at all kinds of enterprises. This is the so-called abiogenic methane. The one that occurs in the marshes is considered to be biogenic - that is, arising from the transformation of organic matter.

Methanogenesis

The biosynthesis of methane (and hence the emergence of a swamp gas) is also called methanogenesis. In this process, the archaea bacteria participate. They are aerobic, that is, they can receive energy for life, avoiding oxygen. Archaea do not have membrane organelles and nuclei.

Bacteria generate methane, restoring single-carbon compounds with carbon alcohols and one-carbon compounds. Another way is the disproportionation of acetate. The energy produced by bacteria is transformed by ATP synthase enzymes. In methanogenesis involved a variety of molecules: coenzymes, methanol, tetrahydrometanopterine, etc.

Methanogens

Science knows 17 genera and 50 species of archaea, capable of generating the basis of swamp gas. They form primitive multicellular colonies. The most studied genome of such archaeos is Methanosarcina acetivorans. They convert to acetate and methane carbon monoxide, using for this enzyme acetate and phosphotransacetylase. There is also a theory that these archaeos in ancient times could have been transformed into thioester, provided that in the then silts there was a high concentration of iron sulphide.

Cause of forest fires

With sufficient emission and concentration, the swamp gas, ignited, can cause a large natural peat and forest fire. Today there is a whole complex of struggle against such phenomena. Special services conduct gas monitoring of the most marsh areas. They are responsible for the prevention and quantitative control of the ratio of the components of a potentially hazardous gas.

For example, one of the most waterlogged in the Moscow region is the eastern Shatursky region. In its waters there are many fish (carp, perch, gobies, carp, pike, carp), newts, frogs, snakes, muskrats, birds (egrets, drink, waders, ducks). The bones of all these animals contain phosphorus. It is processed by bacteria, after which several other substances appear. This is diphosphine and phosphine. They are the main initiators of the chain reaction for spontaneous combustion. The fires started in this way are a serious environmental problem. From fires in swamps, not only forests, but also peatlands burn. The fire can spread into them. Such peat bogs can burn for years.

In Russia, about two-thirds of all mires in the world are concentrated. They are found in the center of the European part of the country, in Western Siberia and in Kamchatka. The total area of wetlands in Russia is about 340 million hectares, 210 of which are covered by forest cover. Most of the gas is produced in the summer. In this period, about two and a half kilograms of methane can be released per hectare per day on the area.

Interaction with oxygen and chlorine

A natural swamp gas, whose chemical formula is CH ₄ , burns with a barely glowing pale flame. The strongest explosion with it occurs when ignited in a mixture containing 7-8 volumes of air and 2 volumes of oxygen. The gas is slightly soluble in water (unlike alcohol). It reacts exclusively with halogens.

When reacted with chlorine, the swamp gas forms methyl chloride CH ₃ Cl. This substance is obtained by laboratory means. For this, the hydrochloric gas is passed to a boiling solution of methyl alcohol and molten zinc chloride. The result is a colorless gas, a characteristic feature of which is a pleasant ethereal smell with a sweetish taste. Under strong pressure or cooling, it thickens into a liquid.

Application and reactions with halogens

Methane (marsh gas), the formula and application of which as a fuel are studied in the school curriculum, actively interacts with halogens. As a result of substitution reactions with these substances, the following compounds are formed: bromide, chloride, fluoride and methylene fluoride. The latter was first obtained by the Russian chemist Alexander Butlerov. Methylene iodide is a strongly refracting light yellowish liquid. The temperature of its boiling is 180 ° C.

What is the name of marsh gas completely replaced by halogens? This is carbon tetrachloride. It was discovered by the French chemist Henri Reno in 1839. It is a liquid with a characteristic spicy odor. It has an anesthetic effect. Another similar substance is carbon tetrabromide. It is extracted from ash from marine plants.

Danger to health

By itself marsh methane is physiologically harmless. It refers to non-toxic paraffin hydrocarbons. This group of substances is characterized by chemical inertness and poor solubility in blood plasma. Air with a high concentration of swamp gas can kill a person only if he suffers from a lack of oxygen.

The initial signs of suffocation (asphyxiation) are manifested when the methane content is from 30%. In this case, the volume of breathing increases, the pulse becomes faster, the coordination of muscle movements is disrupted. But the likelihood of such cases is extremely small. The fact is that methane is lighter than air, which prevents it from accumulating in excessive proportions.

At the same time, researchers equate the action of marsh gas on the human psyche to the action of diethyl ether. This effect can be equated with the narcotic. People who have worked in mines with a high concentration of methane for a long time can see changes in the autonomic nervous system (hypotension, positive eye-reflex reflex, etc.).