Question

Define craking . mention two important methods of craking​

Answer 1

In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors.

Various methods can be used for cracking, eg catalytic cracking and steam cracking:

Catalytic cracking uses a temperature of approximately 550°C and a catalyst known as a zeolite which contains aluminium oxide and silicon oxide.

Steam cracking uses a higher temperature of over 800°C and no catalyst.

Answer 2

Explanation:

Cracking is a reaction in which larger saturated hydrocarbon molecules are broken down into smaller, more useful hydrocarbon molecules, some of which are unsaturated:

1)the original starting hydrocarbons are alkanes

2)the products of cracking include alkanes and alkenes, members of a different homologous series

For example, hexane can be cracked to form butane and ethene:

hexane → butane + ethene

C6H14 → C4H10 + C2H4

The starting compound will always fit the rule for an alkane, CnH2n+2. The first product will also follow this rule. The second product will contain all the other C and H atoms. The second product is an alkene, so it will follow the rule CnH2n.

Types of Cracking:--

1) FCC – Fluid Catalytic Cracking: It is mainly used in petroleum refiners. This process involves the conversion of high molecular weight, high boiling hydrocarbons into olefinic, gases, gasoline and other products.

2) Hydrocracking: It is a catalytic cracking process, where it uses hydrocracking to break C – C bonds. Products produced by this process include diesel, jet fuel, and LPG.

3)Steam Cracking: It is a petrochemical process that involves the breakdown of saturated hydrocarbons into smaller unsaturated hydrocarbons.

4)Thermal Cracking: It is a process that involves breaking of large non-volatile hydrocarbons into gasoline.

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@SulphuricNitrogen