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 and the hydroxide ion acts as a base (unlike in the hydrolysis of a halogenoalkane to form an alcohol).
Elimination Reactions of Halogenoalkanes
Halogenoalkanes can be converted into alkenes by an elimination reaction.
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 and accepts a proton from a C-H bond to form H O.
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.