The gas released from the bottom of water bodies is a marsh gas with an unpleasant odor (another general name is methane). From the point of view of science, this is form, or methyl hydrogen. For the most part, it consists of methane (CH 4 ). It may also contain nitrogen, argon, hydrogen, phosphine, and carbon dioxide.
Key Features
The standard composition, the chemical formula of the swamp gas - all this clearly demonstrates its belonging to the simplest carbon compounds. Around this element, the remaining components are grouped. Swamp gas occurs 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, these are plants that find themselves under water and lack 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 a hole appears accidentally.
Places of education
Despite its rather unambiguous name, bog gas (or, more precisely, methane) is also released from earthen 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 Territory. In Baku, for this reason, from ancient times, there was a legend about the mysterious Baku lights. A natural phenomenon turned out to be mixed with carbon dioxide, nitrogen, and oil vapor by swamp gas.
With the development of industry and mining technology, people have learned how to utilize the released methane. The first such plant appeared in Pennsylvania. Swamp gas is distinguished by the fact that it forms continuously, it can be found in any swamp or pond. Often for this it is enough just to touch the silt with a stick. After that, gas bubbles float to the water surface.
The basis of swamp gas
The formation of the main component of natural gas (methane) helps bacteria. 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 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 intestines. It contains the exhalation products 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 marsh gas is known 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 swamp gas and similar compounds for a long time terrified people who explained what was happening with superstitions. 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 Davy's 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 excluded the possibility of ignition of a combustible gas mixture.
Discovery story
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 to burn. In addition, it was Volta who determined that swamp gas is a source of carbonic acid.
The Italian discovered methane on the border of Switzerland and Italy near Lake Lago Maggiore. The inspiration for the scientist was an article by an American scientist and politician Benjamin Franklin about the phenomenon of “combustible air”. Volta was the first to receive methane, collecting gas emitted by the swamp.
Continued research
Other important researchers of the natural phenomenon were the French chemist Claude Bertollet 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 mystery of the explosive substance was hidden in its main component - methane. It has been defined as a light hydrocarbon gas (as opposed to a heavy ethylene hydrocarbon gas). Over time, another term was established - methyl hydrogen. Henry's research was continued by John Dalton and Jens Jacob Berzelius.
In 1813, the English chemist and geologist Humphry Davy analyzed the 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 released in the mines is identical to the similar mixture in the swamps.
Environmental impact
Methane characteristic of bog gas arises as a result of certain chemical reactions. First of all, it is the dry distillation of organics (for example, peat or wood). Chemically pure methane is obtained by decomposition of zincmethyl with water (in this case zinc oxide is produced). Today, this substance attracts the attention of many ecologists because of its participation in the formation of the greenhouse effect. This happens 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. Environmentalists estimate the contribution of methane to enhancing the greenhouse effect at about 30%.
The properties, composition, and chemical formula of bog gas are being studied today 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. An analogue of swamp gas is produced at various enterprises. This is the so-called abiogenic methane. The one that occurs in the swamps is considered biogenic - that is, that arose as a result of transformations of organic matter.
Methanogenesis
The biosynthesis of methane (and hence the occurrence of swamp gas) is also called methanogenesis. Archean bacteria are involved in this process. They are aerobic, that is, they can receive energy for life, doing without oxygen. Archaea do not have membrane organelles and nuclei.
Bacteria generate methane, reducing carbon compounds using carbon alcohols and carbon compounds. Another way is to disproportionate acetate. The energy generated 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 that can generate 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 acetate kinases and phosphotransacetylases. There is also a theory that these archaea in ancient times could be transformed into a thioether, provided that in that sludge there was a high concentration of iron sulfide.
Cause of forest fires
With sufficient emission and concentration, the swamp gas, if ignited, can cause a large natural peat and forest fire. Today, there is a whole range of struggle with such phenomena. Special services conduct gas monitoring of the most wetlands. 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 swampy in the Moscow region is the eastern Shatursky district. In its reservoirs there are a lot of fish (crucian carp, perches, gobies, carps, pikes, common carp), newts, frogs, snakes, muskrats, birds (herons, drink, 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. The fires that started in this way are a serious environmental problem. From fires in the swamps, not only forests burn , but also peatlands. Fire can spread deep into them. Such peatlands can burn for years.
About two thirds of all the marshes of 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 gas is produced in the summer. In such a period, about two and a half kilograms of methane can be released per day on an area of one hectare.
Interaction with oxygen and chlorine
Natural swamp gas, the chemical formula of which is CH 4 , burns with a faintly luminous pale flame. The strongest explosion with it occurs when ignited in a mixture containing 7-8 volumes of air and 2 volumes of oxygen. Gas is slightly soluble in water (unlike alcohol). It reacts exclusively with halogens.
When interacting with chlorine, bog gas forms methyl chloride CH 3 Cl. This substance is obtained by laboratory means. For this, hydrochloric gas is passed into a boiling solution of methyl alcohol and molten zinc chloride. The result is a colorless gas, the characteristic feature of which is a pleasant etheric smell with a sweetish taste. With strong pressure or cooling, it thickens into a liquid.
Application and reactions with halogens
Methane (swamp gas), the formula and use 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 last of them was first obtained by the Russian chemist Alexander Butlerov. Methylene iodide is a highly yellowish, light-refracting liquid. Its boiling point is 180 ° C.
What is the name of a swamp gas completely replaced by halogens? It is carbon tetrachloride. It was discovered by the French chemist Henri Renaud in 1839. It is a liquid with a characteristic spicy smell. It has an anesthetic effect. Another similar substance is carbon tetrabromide. It is extracted from ash from marine plants.
Health hazard
Marsh methane itself 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 experiences a lack of oxygen.
The initial signs of asphyxiation (asphyxia) are manifested with a methane content of 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 action of diethyl ether. A similar effect can be equated with a narcotic one. In people who have worked in mines with a high concentration of methane for a long time, changes in the autonomic nervous system (hypotension, positive ocular reflex, etc.) are observed.