H | H-C-H | H
A principal component of natural gas, methane is a significant fuel. Burning one molecule of methane in the presence of oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O (water):
- CH4 + 2O2 → CO2 + 2H2O
The strength of the carbon-hydrogen covalent bond in methane is among the strongest in all hydrocarbons, and thus its use as a chemical feedstock is limited. The search for catalysts which can facilitate C-H bond activation in methane and other low alkanes is an area of research with considerable industrial significance.
Principal sources are
- decomposition of organic wastes
- natural sources (marshes) : 23 %
- fossil fuel extraction : 20 % See Coal bed methane extraction
- the processes of digestion of animals (cattle) : 17 %
- bacteria found in rice plantations : 12 %
- biomass anaerobic heating or combustion
80% of the world emissions are of human source. They come primarily from agricultural and other human activities. During the past 200 years, the concentration of this gas in the atmosphere doubled, passing from 0.8 to 1.7 ppm.
See also methyl group, which is a functional group similar to methane.