When alkyl halide having at least one β-hydrogen is boiled with alcoholic solution of potassium hydroxide (KOH), an alkene is formed due to elimination of hydrogen atom from β-carbon and halogen atom from α-carbon, is called dehydrohalogenation.
Tertiary butyl bromide when heated with alcoholic solution of potassium hydroxide forms isobutylene.
This reaction is called β-elimination (or 1,2- elimination) reaction as it involves elimination of halogen and a β-hydrogen atom.
As hydrogen and halogen is removed in this reaction it is also known as dehydrohalogenation reaction.
