Views: 0 Author: Site Editor Publish Time: 2023-10-23 Origin: Site
The main component of natural gas is methane. It is a colorless, odorless, tasteless, flammable gas. Methane is a nonpolar covalent compound.
Hence it is slightly soluble in water but more soluble in organic solvents (alcohol, acetone, ether, benzene, toluene etc).
Methane is lighter than air. The vapour density of methane is half of the vapour density of air.
When cooled by applying pressure, methane first becomes liquid and then solidifies. The boiling point of methane is — 161.4ᵒC and the melting point is — 183 ᵒC.
The density of methane is 0.66 kg / cubic meter at 298K temperature and 1 atmosphere pressure.
Methane is a covalent compound. It is a non polar compound and hence the dipole moment of methane is 0D.
From primary analysis and vapor density found that the molecular formula of methane is CH4. That is, methane consists of one C-atom and four hydrogen atoms.
All the four hydrogen atoms of methane are equivalent. Because of substitution of one hydrogen atom by any univalent atom or group give only one mono substituted compound.
This implies that all four hydrogen atoms of methane are equivalent. The central carbon atom is sp3 hybridized.
So the geometry of methane is pure tetrahedral. The H — C — H bond angle is 109ᵒ28’. The C — H bond length is 1.09 Å.
There are different methods for the preparation of methane, namely laboratory method, synthetic method and reduction method at room temperature.
In laboratory method, anhydrous sodium acetate is mixed with dry sodalime by 1:3 rations and then heated. As a result, impure methane is obtained.
CH3COONa +NaOH ⟶ CH4 + Na2CO3
These impurities are acetylene, ethylene, hydrogen, water vapor etc. After purification of these impurities, we can get pure methane.
In this method, a mixture of carbon monoxide or carbon dioxide and hydrogen is passed over a nickel dust at 300ᵒC — 400ᵒC temperature and as result of this methane is obtained.
CO +3H2 ⟶ CH4 + H2O | CO2 + 4H2 ⟶ CH4 + 2H2O
Preparation of methane at room temperature:
At room temperature, on reduction of methyl iodide by ethyl alcohol and Zn-Cu couple pure methane is obtained. Again, methane is also prepared by hydrolysis of aluminium carbide.
CH3-I + Zn + C2H5-OH ⟶ CH4 + Zn (OC2H5I)
Methane is the main component of CNG which is mainly used as fuel. It is a best fuel. Because of its combustion causes very low levels of air pollution.
In addition, its calorific value (5000 Btu per cubic foot) is much higher than other fuels.
For the above reason, methane is predominantly used as fuel. It is used as fuel in ovens, homes, water heaters, furnaces, cars, turbines and other things.
In many cities, methane is piped from house to house for domestic heating and cooking.
Again, refined liquid methane is mixed with liquid oxygen and used as rocket fuel.
As a rocket fuel, methane offers the advantage over kerosene of producing small exhaust molecules.
In addition, turbines or steam generators generate electricity using methane gas as fuel.
In addition to fuel, methane has many other uses. For example, carbon dioxide obtained from methane's heat dissipation is used to make paint, printing inks and to make car tires.
Necessary chemicals such as methyl chloride, acetylene, formaldehyde and methanol are produced from methane.
The gas mixture (CO + H2) obtained by the reaction of steam with methane is used in the production of methanol and hydrogen gas.