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Methane


Methane
Methane is the simplest hydrocarbon is a gas with the chemical formula CH4. Pure methane is odorless, but if used for commercial purposes, usually add a little sulfur smell to detect possible leaks.

As the main component of natural gas, methane is the primary fuel source. Burning one molecule of methane with oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O (water):
CH4 + 2O2 → CO2 + 2H2O

Methane is a greenhouse gas. The concentration of methane in the atmosphere in 1998, expressed in mole fraction, was 1745 nmol / mol (parts per billion), up from 700 nmol / mol in 1750. In 2008, the methane content in the atmosphere has increased to 1800 nmol / mol.


A. Chemistry and bonding characteristics

Methane is a tetrahedral molecule with four CH bonds are equivalent. Electronic structure can be explained by four bonding molecular orbitals resulting from the valence orbitals of C and H are complementary. Small molecular orbital energy resulting from the 2s orbital on carbon atom paired with the 1s orbitals of four hydrogen atoms.

At room temperature and standard pressure, methane is a colorless gas that is odorless darn. The smell of methane (which are made available for security reasons) resulting from the addition of odorants such metanathiol or etanathiol. Methane has a boiling point of -161 ° C (-257.8 ° F) at a pressure of 1 atmosphere. [6] As a gas, methane is flammable only when the concentration reaches 5-15% in air. Liquid methane does not burn unless it is given a high pressure (4-5 atmospheres).

B. The chemical reaction

The main reactions in methane is burning, steam reformation into syngas, and halogenation. In general, methane reactions difficult to control. Partial oxidation to methanol, for example, a reaction which is rather difficult to do because of the chemical reactions that occur remain to form carbon dioxide and water, although the amount of oxygen available is insufficient. Enzymes monooksigenase methane can be used to produce methanol from methane, but due to the limited amount which can not be used in industrial-scale reactions.

C. Acid-base reactions

As with other hydrocarbons, methane is a very weak acid. Its pKa values in DMSO estimated 56. Methane can not be deprotonated in solution, but the conjugate basanya with metillitium already known. Protonation of methane can be prepared by reacting them with acid to produce CH5 + super, sometimes called ion metanium.

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