Alkene Reactions Flashcards
Alkene Reactions
Addition (halogenation)
Addition (hydrohalogenation)
Oxidation (combustion)
Addition (hydration)
Reduction (hydrogenation)
Addition (polymerisation)
Alkene addition (halogenation)
Alkene + Halogen –> Dihaloalkane
Conditions: None
Alkene addition (halogenation) example ( C2H4 + Br2 )
C2H4 + Br2 –> C2H4Br2
Conditions: None
Alkene addition (hydrohalogenation)
Alkene + Hydrogen Halide –> Haloalkane
Conditions: None
Alkene addition (hydrohalogenation) example ( C3H6 + HCl )
C3H6 + HCl –> C3H7Cl
Conditions: None
Markovnikov’s Rule
Alkene addition (hydrohalogenation)
‘Rich get richer’
The product formed the most is the one where the hydrogen atom attaches to the carbon with the most hydrogen atoms
Alkene oxidation (combustion)
Alkene + Oxygen –> Carbon Dioxide + Water + Energy
Conditions: None
Alkene oxidation (combustion) example ( 2C3H6 + 9O2 )
2C3H6 + 9O2 –> 6CO2 +6H2O
Negative enthalpy
Conditions: None
Alkene addition (hydration)
Alkene + Water –> Alcohol
Conditions: H3PO4, heat
Alkene addition (hydration) example ( C3H6 + H2O )
C3H6 + H2O –> C3H7OH
Consider minor and major product
Conditions: H3PO4, heat
Alkene reduction (hydrogenation)
Alkene + Hydrogen –> Alkane
Conditions: Ni, heat
Alkene reduction (hydrogenation) example ( C3H6 + H2 )
C3H6 + H2 –> C3H8
Conditions: Ni, heat
Alkene addition (polymerisation)
Alkene + Alkene + Alkene … –> Polyalkene
Conditions: Catalyst, pressure, heat
Alkene addition (polymerisation) example ( C2H4 monomers )
C2H4 + C2H4 –> (C2H4)n
Determining whether an alkene is present
The presence of a carbon double bond is determined using bromine water. The bromine solution becomes colourless in the presence of an alkene. Potassium permanganate also decolourises in the presence of a double bond.
