Alkanes: Modification of Alkanes by Cracking

Question 1

Why is cracking needed?

Answer 1

• There is a shortage of shorter chain fractions and a surplus of longer chain ones found in crude oil
• The longer chain fractions are in lower demand and are less economically valuable

Question 2

Define the term cracking

Answer 2

• A process where long chain hydrocarbons are broken into smaller chain hydrocarbons
• It involves breaking C-C bonds

Question 3

What are the two types of cracking?

Answer 3

• Thermal cracking

- Catalytic cracking

Question 4

What is thermal cracking?

Answer 4

• Requires high temperature (around 1200K)
• Requires high pressure (around 7000kPa)
• Produces a large proportion of alkenes and lower proportions of branched alkanes

Question 5

What is catalytic cracking?

Answer 5

• Requires relatively lower temperatures (around 700K)
• Requires only slight pressure.
• Produces a large proportion of arenes and branched alkanes needed to produce motor fuels
• Uses a zeolite catalyst