AS-Level Halogenoalkanes
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Halogenoalkanes can be converted to alkenes in an elimination reaction.
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By reacting halogenoalkanes with hydroxide ions in ethanolic conditions (anhydrous), an alkene and not an alcohol is formed.
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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).
QUICK NOTES
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.
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