# Alkanes: Cracking

## Cracking: Steam Cracking

The petrochemical industry uses steam cracking for the production of lower olefins, such as ethylene and propylene. $C4$ hydrocarbons isobutene und butadiene are produced as side-products.

Higher-molecular hydrocarbons are heated at 850 $°C$ in the presence of water vapor to give this process its name. Oil-producing countries frequently use liquid-gas (mixtures of ethane, propane and butane) as starting material, while other countries use the heavier hydrocarbons ($C4$ - $C12$) from the crude oil distillate. The process is carried out in pipe reactors made from chromium-nickel steel.

The main products of this process, ethylene and propylene, are used widely. Both are used as starting materials for the syntheses of other chemical compounds and for the production of ( and ).

Fig.1
Ethylene produced by steam cracking
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