Is Luca's reagent used for preparation of haloalkanes from tertiary alcohol?Also is there any method of differentiating between primary , secondary and tertiary alcohols using luca's reagent?
A solution of conc.HCl and anhydrous ZnCl2 is called as Lucas' reagent. It is used to differentiate between primary, secondary and tertiary alcohols. It is based on the reactivity of alcohols with hydrogen halide.
ROH + HCl RCl + H2O
The ease of formation of corresponding carbocation of alcohol decides the reactivity.
Stability of carbocations:
Tertiary > secondary > primary
Due to presence of alkyl groups which have +I effect, the positive charge gets reduced and carbocation get stabilized.
Hence, tertiary alcohols react faster with Lucas' reagent.
ROH + HCl RCl + H2O
The ease of formation of corresponding carbocation of alcohol decides the reactivity.
Stability of carbocations:
Tertiary > secondary > primary
Due to presence of alkyl groups which have +I effect, the positive charge gets reduced and carbocation get stabilized.
Hence, tertiary alcohols react faster with Lucas' reagent.