Methane is the simplest organic compound and hydrocarbon, with the chemical formula CH4 and molecular weight of 16.043 g/mol. Methane is used in chemical industry to produce a mixture of carbon monoxide and hydrogen called the synthesis gas. Mainly, methane is utilized as a fuel for electricity generation and in domestic ovens and furnaces. Methane is the principal component (~90 percent) of the natural gas.
According the U.S. government official statistics, Russia has the largest reserve (1,680 trillion cubic feet (tcf) of the natural gas in the world. The Russian company Gazprom is the world’s largest natural gas producer (estimated 19.4 tcf in 2007) exporter. Russia exports large amounts of the natural gas to European countries. As of 2006, Germany and Italy depend on the Russian gas on 36 and 25 percent, respectively. However, it is practically the only source of the natural gas for countries such as Czech Republic, Slovakia, Finland, Bulgaria, Greece and Hungary.
Methane gas is colorless, odorless and tasteless. Smell of the natural gas used for domestic needs comes from additives (e.g. methyl mercaptan) and constitutes a safety measure. Methane gas density is 0.717 kg/m3, and it is lighter than air. Methane becomes liquid below 112 K and solidifies under 90.5 K. This gas is only poorly soluble in water, but is soluble in organic solvents.
Combustion of methane is the most important reaction producing a good amount of heat (890 kJ/mole). That explains the role of methane as a major energy source: CH4 + 2O2= CO2 + 2H2O. Another typical chemical transformation for methane is a radical chain reaction initiated by light. It reacts with chlorine gas Cl2 to produce a mixture of products: CH4 + CL2 —> CH3Cl+ CH2Cl2+ CHCl3+ CCL4. It also undergoes decomposition under the high temperature (~1500K) to form acetylene: 2CH4 = C2H2+3H2
Methane is not toxic and does not pose the immediate health hazard. However, high concentrations of the gas may reduce the oxygen percentage in air and cause suffocation. Methane is the flammable gas and poses an explosion hazard when its concentration in air reaches 5 to 15 percent. If methane burns out under insufficient oxygen conditions, highly toxic carbon monoxide is produced.
Methanotrophic bacteria, found in many habitats, utilize methane as their sole carbon and energy source. The bacteria oxidize methane to methanol using special enzymes. These bacteria play an essential role to reduce the methane concentration in atmosphere. Methane is the gas that causes the greenhouse effect in the atmosphere, leading to global warming.
- Organic Chemistry; F. Carey; 2007
- U.S. Government official energy statistics
- The Biochemistry of Methane Oxidation; A.S. Hakemian and A.C. Rosenzweig, The Annual Review of Biochemistry, Vol 76, pp. 223–241; 2007
- Image by Flickr.com, courtesy of Conan