Alkene reactions

• Alkenes are made by catalytic cracking of petroleum fractions of alkanes

  Long alkane ---> Shorter alkane + alkene

  or

  Catalytic cracking of ETHANE to make alkene + hydrogen:

  C2H6 -->C2H4 (alkene) + H2

  
  

  Conditions: 500C + Al2O3 catalyst
• Combustion reaction:

  General Equation: Alkene + Oxygen --> Carbon Dioxide + Water

  Conditions: Ignite in air/oxygen
• Addition/Hydrogenation reaction (to make alkanes)

  General Equation: Alkene + Hydrogen --> Alkane

  Conditions: 180C + Nickel Catalyst

  (Opposite of ethane catalytic reaction)

  C2H4 + H2 ---> C2H6
• Addition/Halogenation reaction:

  General Equation: Alkene + Halogen --> Dihalogenoalkane

  Conditions: None

  (Double bond test: Alkene + Aqueous bromine = Orange/brown to colourless)
• Addition Reaction:

  General Equation: Alkene + Steam --> Alcohol

  Conditions:

  1. Phosphoric (V) acid catalyst
  2. 300C
  3. 60 atm pressure