Catalytic Cracking Flashcards
Why is catalytic cracking needed?
Catalytic cracking is needed to satisfy the demand for petrol by converting the heavier fractions obtained from crude oil into shorter-chain hydrocarbons that can be used
Define catalytic cracking
Catalytic cracking is the breaking down of long-chain hydrocarbon molecules by the action of heat and catalysts into short-chain molecules for which there is greater demand
What type of short-chained hydrocarbons usually form from catalytic cracking?
Alkanes are usually formed
What are the short-chained hydrocarbons formed from catalitic cracking used for?
They are used in petrol as they have higher octane numbers
Why are short-chained hydrocarbons used in petrol?
As they have higher octane numbers
Why are the hydrocarbons formed from catalytic cracking used in petrol?
They short-chain hydrocarbons are highly branched which means that the petrol formed from these has a higher octane number
How is cracking carried out in an oil refinery?
This is done by heating the heavier fractions such as fuel oil, diesel oil and kerosene in the presence of a catalyst
Give three examples of heavier fractions of crude oil that can be cracked into short-chained, highly branched hydrocarbons.
Fuel oil
Diesel
Kerosene
What does fuel oil, diesel and kerosene have to be heated in the presence of in order for cracking to take place?
They must be heated in the presence of a catalyst
What is one of the most common forms of catalytic cracking?
The conversion of an alkane into a branched alkane and an alkene
What must one of the products be if an alkane is split?
One of the products must be unsaturated
Other than the high octane, short-chained, highly-branched alkanes that result from catalytic cracking, what is another benefit of catalytic cracking?
A second benefit of cat cracking is that the alkenes produced (from the cracking of an alkane) are important as feedstock for the petrochemicals industry
What can ethene (product of catalytic cracking of an alkane) be used to make?
It can be used to make polyethene
What is a product of the catalytic cracking of an alkane that can be used to make polyethene?
Ethene
What can propene (a product of cat cracking of an alkane) be used to make?
Polypropene
