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CAS NUMBER: 74-82-8
MOLECULAR FORMULA: CH₄
MOLECULAR WEIGHT: 16,04 g/mol
Methane is a chemical compound with the chemical formula CH4 (one carbon atom bonded to four hydrogen atoms).
Methane is a group-14 hydride, the simplest alkane, and the main constituent of natural gas.
The relative abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it poses technical challenges due to its gaseous state under normal conditions for temperature and pressure.
Naturally occurring methane is found both below ground and under the seafloor and is formed by both geological and biological processes.
The largest reservoir of methane is under the seafloor in the form of methane clathrates.
When methane reaches the surface and the atmosphere, it is known as atmospheric methane.
The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases.
Methane has also been detected on other planets, including Mars, which has implications for astrobiology research.
Methane was discovered and isolated by Alessandro Volta between 1776 and 1778 when studying marsh gas from Lake Maggiore.
Methane is the major component of natural gas, about 87% by volume.
The major source of methane is extraction from geological deposits known as natural gas fields, with coal seam gas extraction becoming a major source.
Methane is associated with other hydrocarbon fuels, and sometimes accompanied by helium and nitrogen.
Methane is produced at shallow levels (low pressure) by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface.
In general, the sediments that generate natural gas are buried deeper and at higher temperatures than those that contain oil.
Methane is generally transported in bulk by pipeline in its natural gas form, or by LNG carriers in its liquefied form; few countries transport it by truck.
Methane, colourless, odourless gas that occurs abundantly in nature and as a product of certain human activities.
Methane is the simplest member of the paraffin series of hydrocarbons and is among the most potent of the greenhouse gases.
Methanes chemical formula is CH4.
Methane is lighter than air, having a specific gravity of 0.554.
Methane is only slightly soluble in water.
Methane burns readily in air, forming carbon dioxide and water vapour; the flame is pale, slightly luminous, and very hot.
The boiling point of methane is −162 °C (−259.6 °F) and the melting point is −182.5 °C (−296.5 °F).
Methane in general is very stable, but mixtures of methane and air, with the methane content between 5 and 14 percent by volume, are explosive.
In nature, methane is produced by the anaerobic bacterial decomposition of vegetable matter under water (where it is sometimes called marsh gas or swamp gas).
Wetlands are the major natural source of methane produced in this way. Other important natural sources of methane include termites (as a result of digestive processes), volcanoes, vents in the ocean floor, and methane hydrate deposits that occur along continental margins and beneath Antarctic ice and Arctic permafrost.
Methane also is the chief constituent of natural gas, which contains from 50 to 90 percent methane (depending on the source), and occurs as a component of firedamp (flammable gas) along coal seams.
Methane that is produced and released into the atmosphere is taken up by methane sinks, which include soil and the process of methane oxidation in the troposphere (the lowest atmospheric region).
Most methane produced naturally is offset by its uptake into natural sinks.
Anthropogenic methane production, however, can cause methane concentrations to increase more quickly than they are offset by sinks.
Since 2007 methane concentrations in Earth’s atmosphere have increased by 6.8–10 parts per billion (ppb) per year.
By 2020 atmospheric methane had reached 1873.5 ppb, some two to three times higher than preindustrial levels, which hovered at 600–700 ppb.
Methane is emitted during the production and transport of coal, natural gas, and oil.
Methane emissions also result from livestock and other agricultural practices, land use and by the decay of organic waste in municipal solid waste landfills.
Methane is a colorless odorless gas.
Methane is also known as marsh gas or methyl hydride.
Methane is easily ignited. The vapors are lighter than air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket.
Methane is used in making other chemicals and as a constituent of the fuel, natural gas.
Methane is a one-carbon compound in which the carbon is attached by single bonds to four hydrogen atoms.
Methane is a colourless, odourless, non-toxic but flammable gas (b.p. -161℃).
Methane has a role as a fossil fuel, a member of greenhouse gas and a bacterial metabolite.
Methane is a conjugate acid of a methanide.
Methane is gas that is found in small quantities in the atmosphere. Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. Methane is a powerful greenhouse gas.
Although the concentration of methane in Earth's atmosphere is small (around 1.8 parts per million), it is an important greenhouse gas because it is such a potent heat absorber.
The concentration of methane in our atmosphere has risen by about 150% since 1750, apparently largely due to human activities.
Methane accounts for about 20% of the heating effects by all of the greenhouse gases combined.
Both natural and human sources supply methane to Earth's atmosphere.
Methane is a powerful greenhouse gas emitted by human activities such as leakage from natural gas systems and the raising of livestock, as well as by natural sources such as wetlands.
Methane has a direct influence on climate, but also a number of indirect effects on human health, crop yields and the quality and productivity of vegetation through its role as an important precursor to the formation of tropospheric ozone.
Methane is a short-lived climate pollutant with an atmospheric lifetime of around 12 years.
While Methanes lifetime in the atmosphere is much shorter than carbon dioxide (CO2), it is much more efficient at trapping radiation.
Per unit of mass, the impact of methane on climate change over 20 years is 86 times greater than CO2; over a 100-year period it is 28 times greater.
Methane is generally considered second to carbon dioxide in its importance to climate change.
The presence of methane in the atmosphere can also affect the abundance of other greenhouse gases, such as tropospheric ozone, water vapor and carbon dioxide.
Methane (CH4) is an important component of aquatic carbon cycling. Methane production is performed by bacteria under strictly anoxic conditions in sediments, but can still account for up to 56% of the total carbon mineralization.
Subsequent microbial oxidation of CH4, primarily occurring in oxic sediment or water layers, consumes a large proportion of the produced CH4.
Methane is a colorless, odorless, flammable hydrocarbon gas that is the simplest alkane.
The root word, met, in methane is derived from the Greek root word methe meaning wine.
Methylene was used in the early 19th century as the name for methanol, which is wood alcohol, CH3OH.
Methylene comes from methe + hydē, the latter being the Greek word for wood, so methylene would mean wine from wood.
Methane got the names methylene and wood alcohol because it was discovered by Robert Boyle (1627–1691) in the 17th century by the destruction distillation of wood.
Destructive distillation involves heating in the absence of air.
Methane is the principal component of natural gas, with most sources containing at least 75% methane.
Methane production occurs naturally through a process called methanogenesis.
Methanogenesis involves anaerobic respiration by single-cell microbes collectively called methanogens.
Methane is a potent greenhouse gas, trapping 86 times more heat in the atmosphere than carbon dioxide.
In fact, nearly 20% of the planet’s warming can be attributed to methane.
And, because Methane’s often paired with other toxic pollutants such as benzene, formaldehyde, and ethylbenzene, the release of methane into the air can cause debilitating health problems for the millions of people who live near oil and gas operations.
Each year, fossil fuel companies leak or deliberately vent 13 million metric tons of methane into the atmosphere during oil and gas operations, which, according to a new study, is 60% more than the Environmental Protection Agency (EPA) has estimated.
Oil, gas and coal production are the largest industrial sources of methane emissions.
USES:
Methane is used in industrial chemical processes and may be transported as a refrigerated liquid (liquefied natural gas, or LNG).
While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air.
Gas pipelines distribute large amounts of natural gas, of which methane is the principal component.
Methane is used as a fuel for ovens, homes, water heaters, kilns, automobiles, turbines, etc.
Activated carbon is used to store methane.
Refined liquid methane is used as a rocket fuel, when combined with liquid oxygen, as in the BE-4 and Raptor engines.
As the major constituent of natural gas, methane is important for electricity generation by burning Methane as a fuel in a gas turbine or steam generator.
Compared to other hydrocarbon fuels, methane produces less carbon dioxide for each unit of heat released.
At about 891 kJ/mol, methane's heat of combustion is lower than that of any other hydrocarbon.
However, Methane produces more heat per mass (55.7 kJ/g) than any other organic molecule due to its relatively large content of hydrogen, which accounts for 55% of the heat of combustion but contributes only 25% of the molecular mass of methane.
In many cities, methane is piped into homes for domestic heating and cooking.
In this context Methane is usually known as natural gas, which is considered to have an energy content of 39 megajoules per cubic meter, or 1,000 BTU per standard cubic foot.
Liquefied natural gas (LNG) is predominantly methane (CH4) converted into liquid form for ease of storage or transport.
As a liquid rocket fuel, methane offers the advantage over kerosene of producing small exhaust molecules.
This deposits less soot on the internal parts of rocket motors, reducing the difficulty of booster re-use.
The lower molecular weight of the exhaust also increases the fraction of the heat energy which is in the form of kinetic energy available for propulsion, increasing the specific impulse of the rocket.
Liquid methane also has a temperature range (91–112 K) nearly compatible with liquid oxygen (54–90 K).
Methane is an important source of hydrogen and some organic chemicals.
Methane reacts with steam at high temperatures to yield carbon monoxide and hydrogen; the latter is used in the manufacture of ammonia for fertilizers and explosives.
Other valuable chemicals derived from methane include methanol, chloroform, carbon tetrachloride, and nitromethane.
The incomplete combustion of methane yields carbon black, which is widely used as a reinforcing agent in rubber used for automobile tires.
As a constituent in cooking and illuminating gas; in the production of ammonia, methanol, and chlorohydrocarbons; it occurs in natural gas and is produced by the decomposition of organic matter.
Methane is an important starting material for numerous other chemicals.
The most important of these are ammonia, methanol, acetylene, synthesis gas, formaldehyde, chlorinated methanes, and chlorofl uorocarbons.
Methane is used in the petrochemical industry to produce synthesis gas or syn gas, which is then used as a feedstock in other reactions.
Synthesis gas is a mixture of hydrogen and carbon monoxide.
Methane is widely distributed in nature.
As adeep earth gas, Methane is outgassing from earth’scrust.
Methane is also present in the atmosphere(0.00022% by volume).
Methane is the prime constituentof natural gas (85–95% concentration).
Methane is formed from petroleum crackingand decay of animal and plant remains.
Methane isfound in marshy pools and muds. Methaneis used as a common heating fuel in naturalgas; in the production of hydrogen, acetylene,ammonia, and formaldehyde; and as acarrier gas in GC analysis.
Methane is used primarily as a fuel to make heat and light.
Methane is also used to manufacture organic chemicals.
Methane can be formed by the decay of natural materials and is common in landfills, marshes, septic systems, and sewers.
Methane is soluble in alcohol, ether, benzene, and organic solvents.
Methane is incompatible with halogens, oxidising materials, and combustible materials. Methane evaporates quickly.
Methane gas is present in coal mines, marsh gas, and sludge degradations.
Methane can also be found in coal gas.
Pockets of methane exist naturally underground.
In homes, methane may be used to fuel a water heater, stove, and clothes dryer.
Also, incomplete combustion of gas also produces carbon monoxide. Methane gas is flammable and may cause flash fire.
Methane forms an explosive mixture in air at levels as low as 5%. Electrostatic charges may be generated by flow and agitation.
Methane (CH4) is a colorless gas produced from a highly reduced paddy field.
This odorless gas is also produced by decomposing organic matter in sewage and marshes.
Methane is the chief constituent of natural gas.
Methane occurs in coal gas and water gas and is produced in petroleum refining.
There is now enough evidence to suggest that rice cultivation results in increased methane emission to the atmosphere.
The reasons for interest in methane are that Methane is an important energy source, which has a global warming potential of about 24.5% (carbon dioxide being loo%), and is responsible for approximately 25% of the anticipated warming.
Atmospheric methane originates mainly from biogenic sources, such as rice paddies and natural wetlands.
Rice paddies account for 15 to 20% of the world's total anthropogenic methane emission.
In addition to the role of rice plant in methane emission, Methane also plays a significant role in methane oxidation because oxygen transported below the ground by plants, leaks out of the rhizosphere into the sediments, stimulating the methane oxidizing activity.
Most of the methane emitted from rice fields is expected to be from the Asian region as it has 90% of the total world rice harvested area.
Several investigations have demonstrated that methane flux in rice fields is dependent on the variety of rice, water level, fertilizer application and crop phenology
Strategies to mitigate methane emission from paddy soils of the world have been identified, which include (a) a form and dose of nitrogen and other chemical fertilizers, (b) the mode of fertilizer application, (c) water management, and (d) cultivation practices.
Recent studies have indicated that methane emission decreased by about 50% after the application of an ammonium based fertilizer, due to oxidation of methane.
The various options to mitigate methane emission are (a) direct seediig of paddy crop, (b) intermittent irrigation, (c) soil amendment with sulphate containing fertilizers, and (d) compost addition in place of fresh organic matter.
Methane is noncorrosive and may be contained by any common, commercially available metals, with the exception of cryogenic liquid applications.
Handling equipment must, however, be designed to safely withstand the temperatures and pressures to be encountered.
At the temperature of liquid methane, ordinary carbon steels and most alloy steels lose their ductility and are considered unsafe for liquid methane service.
Satisfactory materials for use with liquid methane include Type 18-8 stainless steel and other austenitic nickel-chromium alloys, copper, Monel, brass, and aluminum.
-Improve manure management and animal feed quality
-Apply intermittent aeration of continuously flooded rice paddies
-Improve animal health and husbandry by combining herd and health management, nutrition and feeding management strategies
-Introduce selective breeding to reduce emission intensity and increase production
-Promote farm-scale anaerobic digestion to control methane emissions from livestock
-Adopt guidelines on healthy dietary choices
-Carry out pre-mining degasification and recovery and oxidation of methane from ventilation air from coal mines
-Reduce leakage from long-distance gas transmission and distribution pipelines
-Extend recovery and utilization from gas and oil production
-Recover and use gas and fugitive emissions during oil and natural gas production
-Separate and treat biodegradable municipal waste, and turn it into compost or bioenergy
-Upgrade wastewater treatment with gas recovery and overflow control
-Improve anaerobic digestion of solid and liquid waste by food industry
-Upgrade primary waste water treatment
-Divert organic waste
-Collect, capture and use landfill gas
PROPERTIES:
Methane is a tetrahedral molecule with four equivalent C–H bonds.
Methanes electronic structure is described by four bonding molecular orbitals (MOs) resulting from the overlap of the valence orbitals on C and H.
The lowest-energy MO is the result of the overlap of the 2s orbital on carbon with the in-phase combination of the 1s orbitals on the four hydrogen atoms.
Above this energy level is a triply degenerate set of MOs that involve overlap of the 2p orbitals on carbon with various linear combinations of the 1s orbitals on hydrogen.
The resulting "three-over-one" bonding scheme is consistent with photoelectron spectroscopic measurements.
At room temperature and standard pressure, methane is a colorless, odorless gas.
The familiar smell of natural gas as used in homes is achieved by the addition of an odorant, usually blends containing tert-butylthiol, as a safety measure.
Methane has a boiling point of −161.5 °C at a pressure of one atmosphere.
As a gas, Methane is flammable over a range of concentrations (5.4–17%) in air at standard pressure.
Solid methane exists in several modifications.
Presently nine are known.
Cooling methane at normal pressure results in the formation of methane.
This substance crystallizes in the cubic system (space group Fm3m).
The positions of the hydrogen atoms are not fixed in methane I, i.e. methane molecules may rotate freely.
Therefore, Methane is a plastic crystal.
CHEMICAL PROPERTIES:
Methane is a natural, colorless, odorless, and tasteless gas.
Methane is used primarily as fuel to make heat and light.
Methane is also used to manufacture organic chemicals.
Methane can be formed by the decay of natural materials and is common in landfi lls, marshes, septic systems, and sewers.
Methane is soluble in alcohol, ether, benzene, and organic solvents.
Methane is incompatible with halogens, oxidizing materials, and combustible materials.
Methane evaporates quickly.
Methane gas is present in coal mines, marsh gas, and in sludge degradations.
Methane can also be found in coal gas.
Pockets of methane exist naturally underground.
In homes, methane may be used to fuel a water heater, stove, and clothes dryer.
Incomplete combustion of gas also produces carbon monoxide.
Methane gas is flammable and may cause fl ash fi re.
Methane forms an explosive mixture in air at levels as low as 5%.
Electrostatic charges may be generated by flow and agitation.
PRODUCTION:
Methane is the end product of anaerobic decay.
Methane is the major constituent of natural gas, present at concentrations between 600,000 and 800,000 ppm 60 to 80% of natural gas.
Methane collects in coal mines or geologically similar earth deposit sites, evolves as marsh gas, and forms during certain fermentation and sludge degradation processes.
Methane is also produced by decomposition in municipal landfills; concentrations can be as high as 250,000 ppm.
Methane is often accompanied by other low molecular weight hydrocarbons.
STORAGE:
Occupational workers should store methane gas containers away from incompatible substances and handle in accordance with standard set regulations and grounding and bonding if required.
SYNONYM:
(13c)methane
02329_FLUKA
0CB689EE-132E-4559-A597-C79A40192203
14493-06-2
150036-83-2
295477_ALDRICH
3B4-2254
463035_ALDRICH
490210_ALDRICH
74-82-8
8006-14-2
AC1L18XA
AC1Q2825
AG-E-08601
AKOS005166816
AR-1A0383
AR-1A0497
Biodiesels
Biogas
BRN 1718732
C01438
C5M
CH4
CHEBI:16183
CHEMBL17564
CTK2H7747
Fire Damp
HSDB 167
KST-1A1445
KST-1A1563
Marsh gas
metano
methan
methane
Methane in gaseus state
Methane-12C
Methyl hydride
MolPort-018-618-244
Natural gas
OP0UW79H66
R 50
R 50 (refrigerant)
tetrahydridocarbon
UN1971
UN1972
UNII-OP0UW79H66
Carbene
Methylidyne radical
atomic carbon
Medicinal charcoal
Carbon, mesoporous
carbane
Carbon sheet, 3N
