What is the correct order of reactivity of alcohols in the following reaction?
The mixture of HCl and ZnCl2 is called the Lucas Reagent. Secondary and tertiary alcohols react via the SN1 mechanism with the Lucas reagent. The ZnCl2 coordinates to the hydroxyl oxygen, and this generates a far superior leaving group.
When alcohols react with a hydrogen halide, a substitution occurs, producing an alkyl halide and water:
Scope of Reaction: The order of reactivity of alcohols is 3° > 2° > 1°