Cracking of Alkanes and Alkenes

• Manufacture of Alkanes and Alkenes by cracking


  • cracking is the breaking down of large hydrocarbon molecules into smaller hydrocarbon molecules
  • Catalytic cracking takes place when a catalyst is used to speed up the process
  • Conditions : High temperature (600 degree Celsius), 1 atm, aluminium oxide catalyst (Al2O3) and silicon dioxide catalyst (SiO2)
  • Cracking of long chain hydrocarbons can produce short chain alkenes and alkanes, or short chain alkenes and hydrogen gas
• • Cracking is essential for :


  1. producing petrol to supply fuel for running vehicles (Bitumen has low demand -> Cracking -> Petrol that is high in demand)
  2. producing Alkenes that are important in starting materials in the petrochemical industry (10% chemical feedstock)
  3. producing hydrogen gas which is used to manufacture ammonia gas and margarine as a rocket fuel (N2 + 3H2 <-> 2NH3)