Ethene

Ethene

Ethene colorless, flammable gas is the first and typical member of the alkene family. It is produced in large amounts by the cracking and the fractional distillation of petroleum and from natural gas. Ethene is an unsaturated hydrocarbon which is composed of two carbon and four hydrogen atoms. There is a double bond between the two carbons. Each carbon atom of ethene is Sp2 hyberidized which contains three equivalent partially filled Sp2 hybrid orbitals and unhyberidized Pz orbital. The hybrid orbitals are arranged at the three corners of coplaner triangle with an angle of 120º. Two Sp2 hybrid orbitals of carbon atoms overlapp with s atomic orbitals of hydrogen atoms to form a sigma bond between C - H due to the overlapping of Sp2 - S orbitals. The remaining Sp2 hybrid of each carbon atom overlap with the Sp2 hybrid orbital of other carbon atom to form sigma bond between C - C due to the overlapping of Sp2 - Sp2.

The unhyberidized Pz orbital of each carbon atom are situated perpendicular to the Sp2 plane and parallel to the unhyberidized Pz orbitals of two different carbon atoms overlap side by side to form a pi bond between carbon atoms.

The chemical formula for ethene is C2H4, which support a standard formula of CnH2n. In 1864, it was discovered that gas leaks from street lights led to stunting of growth, twisting of plants, and abnormal thickening of stems. In 1901, a Russian scientist named Dimitry Neljubow showed that the active component was ethene. Ethene is highly flammable and burn readily in air, forming carbon dioxide and water. The meltig point of ethene is -169 ^oC and boiling point is -103 ^oC. Because of the presence of the double bond in ethene, it is very reactive and readily forms many products such as chloroethane, bromoethane etc.

Uses of Ethane:

Ethylene is involved in the natural process of fruit ripening. Ethene is also known as "ripening hormone" as it's used as a plant hormone to control the ripening and color development of fruit. The ethylene produced by ripened is a gas and can move to other fruits to stimulating their ripening. In commercial situations, ripening can either be sped up (by storing fruit in containers with high ethylene content) or slowed down (by storing them in bins periodically flushed with carbon dioxide to prevent ethylene build up and inhibit further ethylene synthesis). Many commercial fruit producers will alter the rate of ripening. To speed up the process, they can store unripened fruit in containers with high amounts of ethylene gas. To prevent or slow down ripening, carbon dioxide can be used as an ethylene trap.  This not only keeps ethylene levels low but also prevents new ethylene production.

Ethane is also use to prepare plastics. For the preparation of plastic ethene is polymerized. Polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. Ethene is used in the manufacture of many important polymers like polyethene and polyvinyl chloride (PVC). These polymers are used in the manufacture of raincoats, shoe soles, pipes and floor tiles.

Ethanol is prepared from Ethene which is used in antiseptic and some antibacterial soaps and wipes. Ethanol is effective against viruses, fungi and most bacteria but is ineffective against bacterial spores. Ethylene is used in the production of specialty glass for the automotive industry (car glass).  Ethylene is used as oxy-fuel gas in the metal cutting, welding and High Velocity Thermal Spraying.

Ethylene is used as refrigerant, especially in LNG liquefaction plants. It is also used in the extraction of rubber. Ethylene glycol (C2H6O2) which is prepared from Ethene is used as antifreeze in cooling and heating systems, in hydraulic brake fluids, as an industrial humectant, as an ingredient of electrolytic condensers, as a solvent in the paint and plastics industries and in many other things. Ethylene glycol is also used to de-ice airport runways and aircraft. Ethene is a petroleum gas that is useful as industrial gas.