The gas emitted from the bottom of reservoirs is marsh gas with an unpleasant odor (another generalized name is methane). Scientifically, it's formene, or methyl hydrogen. Most of it consists of methane (CH4). It may also contain nitrogen, argon, hydrogen, phosphine and carbon dioxide.
Key Features
Standard composition, chemical formula of swamp gas - all this clearly demonstrates its belonging to the simplest carbon compounds. Other components are grouped around this element. Marsh gas is found in nature in a free state as a mixture with carbon dioxide or nitrogen. It results from the decomposition of organic matter. As a rule, these are plants that are under water and deprived of access to air.
Coal mines are another place where combustible swamp gas is formed. It accumulates among the rocks after the decomposition of organic residues. Numerous voids contribute to this. Such gases escape when an accidental hole appears.
Places of education
Despite its rather unambiguous name, marsh gas (or rather, methane) is also emitted fromearth cracks near 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, there has been a legend about mysterious Baku fires since ancient times. The natural phenomenon turned out to be mixed with carbon dioxide, nitrogen and oil vapours, swamp gas.
With the development of industry and mining technology, people have learned to utilize the released methane. The first such plant appeared in Pennsylvania. Swamp gas is characterized by the fact that it is formed continuously, it can be found in any swamp or pond. Often, it is enough just to touch the silt with a stick. After that, gas bubbles float to the water surface.
Swamp gas base
Bacteria help form the main component of natural gas (methane). Because of them, fermentation of plant fiber begins, contributing to the appearance of methane. The purest methane is believed to be characteristic of the mud volcanoes of the Apsheron and Kerch Peninsulas.
In addition, it occurs in s alt deposits, springs and fumaroles - holes and cracks located at the foot of volcanoes. Methane is present in the human intestine. It contains the exhalation products of some animals. One of the first written evidence of this substance can be considered the writings of the ancient writer Pliny, who mentioned gaseous combustible compounds.
Explosiveness
Most of all swamp gasknown for its 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 marsh gas and similar compounds for a long time terrified people who explained what was happening with superstitions. The reasons for the anomaly became clear only after a scientific study of this phenomenon.
Marsh 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, combustion products were removed using a special grid, thanks to which the possibility of ignition of a combustible gas mixture was excluded.
Discovery history
The Italian scientist Allesandro Volta made a great contribution to the study of swamp gas (methane). In 1776, he proved that this substance is different from hydrogen, since it needs twice as much oxygen to burn. In addition, it was Volta who determined that swamp gas is a source of carbonic acid.
An Italian discovered methane on the border of Switzerland and Italy near Lake Maggiore. The inspiration for the scientist was an article by the American scientist and politician Benjamin Franklin about the phenomenon of "combustible air". Volta was the first to obtain methane by collecting the gas emitted by the swamp.
Research continues
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 swamp gas and distinguished it from ethylene (socalled oil gas).
The secret of the explosive was hidden in its main component - methane. It has been defined as a light hydrocarbon gas (as opposed to the heavy hydrocarbon gas ethylene). Over time, another term was established - methyl hydrogen. Henry's research was continued by John D alton and Jens Jakob Berzelius.
In 1813, the English chemist and geologist Humphrey Davy analyzed firedamp and concluded that this substance was a mixture of methane, carbonic anhydride and nitrogen. So it was proved that the combustible mixture released in the mines is identical to a similar mixture in the swamps.
Ecological impact
Characteristic of swamp gas, methane arises from certain chemical reactions. First of all, this is the dry distillation of organic matter (for example, peat or wood). Chemically pure methane is obtained by decomposition of zinc methyl with water (zinc oxide is produced). Today, this substance attracts the attention of many environmentalists because of its participation in the formation of the greenhouse effect. This is due to the accumulation of methane in the Earth's atmosphere. Swamp gas absorbs thermal radiation in the infrared region of the spectrum. In this parameter, it is second only to pure carbon dioxide. Ecologists estimate the contribution of methane to the enhancement of the greenhouse effect at about 30%.
Properties, composition, chemical formula of marsh gas are being studied today as part of the study of its influence on the atmosphere of our planet. In natural quantities produced by nature itself, it was notdangerous 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. An analogue of swamp gas is produced at various enterprises. This is the so-called abiogenic methane. The one that occurs in swamps is considered biogenic - that is, resulting from the transformation of organic matter.
Methanogenesis
The biosynthesis of methane (and hence the occurrence of swamp gas) is also called methanogenesis. Archaeal bacteria are involved in this process. They are aerobic, that is, they can obtain energy for life without oxygen. Archaea do not have membrane organelles and a nucleus.
Bacteria generate methane by reducing one-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. A variety of molecules are involved in methanogenesis: coenzymes, methanofuran, tetrahydromethanopterin, 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 archaea is Methanosarcina acetivorans. They convert carbon monoxide to acetates and methane using the enzymes acetate kinase and phosphotransacetylase. There is also a theory that these archaea in ancient times could transform into thioether, provided that there was a highiron sulfide concentration.
Cause of forest fires
With sufficient emission and concentration, swamp gas, ignited, can cause a large natural peat and forest fire. Today, there is a whole complex of combating such phenomena. Special services carry out gas monitoring of the most swampy areas. They are responsible for the prevention and quantitative control of the ratio of the components of a potentially dangerous gas.
For example, one of the most swampy in the Moscow region is the eastern Shatursky district. In its reservoirs there are a lot of fish (crucians, perches, gobies, carps, pikes, carp), newts, frogs, snakes, muskrats, birds (herons, bitterns, waders, ducks). The bones of all these animals contain phosphorus. It is processed by bacteria, after which several other substances appear. These are diphosphine and phosphine. They are the main initiators of the chain reaction of spontaneous combustion. Fires started in this way are a serious environmental problem. From fires in swamps, not only forests, but also peat bogs are burning. The fire can spread deep into them. Such peatlands can burn for years.
About two-thirds of all swamps in the world are concentrated in Russia. They are found in the center of the European part of the country, Western Siberia and Kamchatka. The total area of swamps in Russia is about 340 million hectares, 210 of which are covered with forest cover. Most of the gas is produced in the summer. During such a period, about two and a half kilograms of methane can be released per day on an area of \u200b\u200bone hectare.
Interaction with oxygen and chlorine
Natural marsh gas, whose chemical formula is CH4, 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 only reacts with halogens.
When interacting with chlorine, swamp gas forms methyl chloride CH3Cl. This substance is obtained in the laboratory. To do this, hydrochloric gas is passed into a boiling solution of methyl alcohol and molten zinc chloride. The result is a colorless gas characterized by a pleasant ethereal odor with a sweetish taste. Under strong pressure or cooling, it thickens into a liquid.
Use and reactions with halogens
Methane (marsh gas), the formula and use of which as a fuel is 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 last of them was first obtained by the Russian chemist Alexander Butlerov. Methylene iodide is a highly refractive yellowish liquid. Its boiling point is 180 °C.
What is the name of swamp gas, completely replaced by halogens? This is carbon tetrachloride. It was discovered by the French chemist Henri Regnault in 1839. It is a liquid with a characteristic spicy odor. It has an anesthetic effect. Another similar substancecarbon tetrabromide. It is extracted from the ashes of marine plants.
He alth hazard
Swamp methane itself is physiologically harmless. It belongs to non-toxic paraffinic 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 only kill a person if he lacks oxygen.
The initial signs of suffocation (asphyxia) appear when the methane content is from 30%. In this case, the volume of breathing increases, the pulse quickens, the coordination of muscle movements is disturbed. 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 effect of swamp gas on the human psyche to the effect of diethyl ether. A similar effect can be equated to a narcotic. In people who have worked in mines with high concentrations of methane for a long time, changes in the autonomic nervous system (hypotension, positive oculocardial reflex, etc.) can be traced.
