Ethane

Ethane (from the Greek aither ether, and the suffix -ane) is an aliphatic hydrocarbon alkane with two carbon atoms, of formula C₂H₆. Under normal conditions it is gaseous and an excellent fuel. Its boiling point is -88 °C.

It is found in appreciable quantity in natural gas.

History

Ethane was first synthesized in 1834 by Michael Faraday, using electrolysis of a potassium acetate solution. He mistook the hydrocarbon product of this reaction for methane and did not investigate it further.

During the period 1847-1849, in an effort to vindicate the radical theory of organic chemistry, Hermann Kolbe and Edward Frankland produced ethane by reductions of propionitrile (ethyl cyanide) and ethyl iodide with the potassium metal, and, like Faraday, by electrolysis of aqueous acetates. They mistook the product of these reactions for the methyl radical (CH
3), of which ethane (C
2H
6) is a dimer.

This error was corrected in 1864 by Carl Schorlemmer, who showed that the product of all these reactions was actually ethane. Ethane was discovered dissolved in Pennsylvania light crude oil by Edmund Ronalds in 1864.

Technical specifications of ethane

ICSC:0266 CAS:74-84-0 A:1035 EC: 601-003-00-X

Gas mixes well with air, explosive mixtures are easily formed. Ethane has a lower and upper calorific value equal to 21.2 and 23.4 MJ/L.

Fires

Extremely flammable. Dusts, carbon dioxide. Cut off the supply; if this is not possible and there is no risk to the immediate environment, let the fire extinguish itself.

Explosion

Gas/air mixtures are explosive. In case of fire: keep bottle cool by spraying with water. Fight the fire from a protected place.

Spills and Leaks

Evacuate danger area, consult an expert. Ventilation. Never pour water jets on the liquid. (Additional personal protection: self-contained breathing apparatus).

Exhibition

• Liquid can produce freezing.
• Simple asphyxiation.
• Piel: Contact the liquid: freezing.
• Eyes: Contact the liquid: freezing.

Storage

At room temperature, ethane is a highly flammable gas, so to store it, it must be kept in a cold place.

Use

The main use of ethane is the production of ethylene by steam cracking. When diluted with steam and briefly heated to very high temperatures (900°C or higher), the heavy hydrocarbons break down into lighter hydrocarbons, and the saturated hydrocarbons become unsaturated. Ethane is favored for ethylene production because steam cracking of ethane is quite selective for ethylene, while steam cracking of the heavier hydrocarbons produces a mixture of products that is poorer in ethylene and higher in alkenes (olefins), such as propene (propylene) and butadiene, and aromatic hydrocarbons.

Ethane is being investigated experimentally as a feedstock for other basic chemicals. [Oxidative chlorination of ethane has long seemed a potentially cheaper route to vinyl chloride than chlorination of ethylene. Many processes have been patented to produce this reaction, but poor selectivity for vinyl chloride and corrosive reaction conditions (specifically, a reaction mixture containing hydrochloric acid at temperatures above 500°C) have discouraged commercialization of the reaction. most of them. INEOS currently operates a 1000 t/a (tonne per year) ethane-to-vinyl chloride conversion pilot plant in Wilhelmshaven in Germany.

Similarly, the Saudi Arabian company SABIC has announced the construction of a 30,000 t/y plant to produce acetic acid by ethane oxidation in Yanbu. The economic viability of this process may depend on the low cost of ethane near the Saudi oilfields, and it may not be competitive with methanol carbonylation in other parts of the world.

Ethane can be used as a refrigerant in cryogenic refrigeration systems. On a much smaller scale, in scientific research, liquid ethane is used to vitrify water-rich samples for cryoelectron microscopy. A thin film of water rapidly immersed in liquid ethane at -150°C or colder freezes too quickly for the water to crystallize. Slower freezing methods can generate cubic ice crystals, which can disrupt soft structures, damage samples, and reduce image quality by scattering the electron beam before it can reach the detector.

Health and safety

At room temperature, ethane is an extremely flammable gas. When mixed with air at 3.0-12.5% by volume, it forms an explosive mixture.

Some additional precautions are necessary when ethane is stored as a cryogenic liquid. Direct contact with liquid ethane can cause severe frostbite. Until warmed to room temperature, liquid ethane vapors are heavier than air and can flow along the ground or land, collecting in low places; If the vapors encounter a source of ignition, the chemical reaction can flash back to the ethane source from which they evaporated.

Ethane can displace oxygen and become a choking hazard. Ethane does not pose any known acute or chronic toxicological hazard. It is not a carcinogen.