Quick Notes Halogenoalkanes - Elimination Reactions

  • Halogenoalkanes can be converted to alkenes in an elimination reaction.
  • By reacting halogenoalkanes with hydroxide ions in ethanolic conditions (anhydrous), an alkene and not an alcohol is formed.
  • The reaction is carried out under reflux conditions and the hydroxide ion acts as a base (unlike in the hydrolysis of a halogenoalkane to form an alcohol).

Full Notes Halogenoalkanes - Elimination Reactions

Halogenoalkanes can be converted into alkenes by an elimination reaction.

elimination reaction halogenoalkane bromoethane with hydroxide ion to form ethene

A halogenoalkane is reacted with hydroxide ions under reflux in ethanol. Ethanol is used as a solvent to ensure the conditions are anhydrous (no water!).

The hydroxide ion acts as a base, accepting a proton from a C-H bond to form H2O.

The important thing to note is that the OH- ion can act as either a nucleophile or as a base, depending on the conditions it’s reacting in.

halogenoalkane hydrolysis and elimination reaction conditions reagents