Methane



Methane gas is a natural gas which can be used to help create energy. Methane gas is expelled from land fills and is a greenhouse gas and is very potent. Methane is very flammable. At its simplest form, it is Alkane, a simple component of natural gas. It is a tetrahedral molecule and has four C-H bonds. It is colorless and odorless. Methane is the center component of natural gas. It is a fairly potent greenhouse gas. Methane levels are rising quickly, especially over the last decade. Methane is a tetrahedral molecule with four equivalent Carbon and Hydrogen bonds. =How is it used?=

Developing Technologies
NASA is currently running tests as methane becoming the main component in rocket fuel. Methane also emitted from coal that has been converted into electricity, still under investigation.

The principal use of methane is as a fuel. The combustion of methane is highly exothermic. CH 4 (g) + 2 O 2 (g)

CO 2 (g) + 2 H 2 O(l)

H = –891 kJ

**FUEL**
Electrical generation by burning it as a fuel in a gas turbine or steam bioler. Uses less carbon dioxide than hydrocarbon fuels. Mainly domestic heating and cooking uses, uncommonly used as vehicle fuel (claimed to be more environmentally- friendly).



Chemical reactions
Main reactions with methane are: [|combustion], [|steam reforming] to [|syngas] , and [|halogenation]. In general, methane reactions are difficult to control. Partial oxidation to [|methanol], for example, is challenging because the reaction typically progresses all the way to [|carbon dioxide] and [|water] even with incomplete amounts of oxygen. The enzymes [|methane monooxygenase] can produce methanol from methane, but they cannot be used for industrial scale reactions. [|[7]]

Acid-base reactions
Like other hydrocarbons, methane is a very weak acid. Its pKa in [|DMSO] is estimated to be 56. [|[8]] It cannot be deprotonated in solution, but the [|conjugate base] with [|methyllithium] is known. Protonation of methane can be achieved with [|super acids] to give CH5+, sometimes called the [|methanium] ion. Despite the strength of its C-H bonds, there is intense interest in [|catalysts] that facilitate [|C–H bond activation] in methane (and other low [|alkanes] ). [|[9]]

Combustion
In the [|combustion] of methane, several steps are involved. An early intermediate is [|formaldehyde] (HCHO or H2CO ). Oxidation of formaldehyde gives the formyl [|radical] (HCO), which then give [|carbon monoxide] (CO): CH4 + O2 → CO + H2 + H2O The resulting H2 oxidizes to H2O, releasing [|heat]. This reaction occurs very quickly, usually in significantly less than a [|millisecond]. 2 H2 + O2 → 2 H2O Finally, the CO [|oxidizes], forming CO2 and releasing more heat. This process is generally slower than the other chemical steps, and typically requires a few to several milliseconds to occur. 2 CO + O2 → 2 CO2 The result of the above is the following total equation: CH4 + 2 O2 → CO2 + 2 H2O (//ΔH// = −891 [|k][|J] / [|mol] (at standard conditions))

Reactions with halogens
Methane reacts with halogens given appropriate conditions as follows: CH4 + X2 → CH3X + HX where X is a [|halogen] : [|fluorine] (F), [|chlorine] (Cl), [|bromine] (Br), or [|iodine] (I). This mechanism for this process is called [|free radical halogenation], beginning with the attach of Cl· radicals on methane to produce CH3·, which combines with a second Cl· to give [|methyl chloride] (CH3Cl). Similar reactions will produce [|dichloromethane] (CH2Cl2), [|chloroform] (CHCl3), and, ultimately, [|carbon tetrachloride] (CCl4). The energy required to start this reaction comes from UV radiation or heating.

Chemical feedstock
Although there is great interest in converting methane into useful or more easily liquified compounds, the only practical processes are relatively unselective. In the chemical industry, methane is converted to [|synthesis gas], a mixture of [|carbon monoxide] and hydrogen, by [|steam reforming]. This endergonic process (requiring energy) utilizes [|nickel] catalysts and requires high temperatures, around 700–1100 °C: CH4 + H2O → CO + 3 H2 Related chemistries are exploited in the [|Haber-Bosch Synthesis] of ammonia from air, which is reduced with natural gas to a mixture of [|carbon dioxide], [|water] , and [|ammonia]. Methane is also subjected to free-radical [|chlorination] in the production of chloromethanes, although methanol is a more typical precursor. [|[10]]

Biological routes
Main article: [|methanogenesis] Naturally occurring methane is mainly produced by the process of [|methanogenesis]. This multistep process is used by microorganisms as an energy source. The net reaction is: CO2 + 8 H+ + 8 e- → CH4 + 2 H2O The final step in the process is catalysed by the enzyme [|methyl-coenzyme M reductase]. Methanogenesis is a form of [|anaerobic respiration] used by organisms that occupy [|landfill], [|ruminants] (e.g., cattle), and the guts of termites. It is uncertain if plants are a source of methane emissions.

Occurrence
Methane was discovered and isolated by Alessandro Volta between 1776 and 1778 when studying marsh gas from Lake Maggiore. It 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 (see Coal bed methane extraction, a method for extracting methane from a coal deposit, while enhanced coal bed methane recovery is a method of recovering methane from an non-minable coal seams). It is associated with other hydrocarbon fuels, and sometimes accompanied by helium and nitrogen. The gas at shallow levels (low pressure) forms by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface. In general, sediments buried deeper and at higher temperatures than those that contain oil generate natural gas.