What is Grove’s process or method and its mechanism ?

What is Grove’s  process or method ?

When a primary alcohol or a secondary alcohol is treated with HCl gas in the presence of anhydrous ZnCl₂ ( Lewis acid ), primary and secondary alkyl chloride or chloro-alkane is obtained respectively , then this process is called Grove’s  process or Grove’s method .

The reaction proceed through SN² mechanism. An example of Grove’s  process or method with mechanism is shown below,

What is the mechanism of Grove’s  process or method ?

The mechanism of Grove’s process or method occurs through SN² method. That is the mechanism is nucleophilic substitution bimolecular. This is an example of second order reaction.

                                Rate of reaction  = K [ alcohol] [ Cl^– ]

Why t-butyl chloride does not prepared in Grove’s  process or method ?

Tertiary butyl chloride does not prepared in Grove’s  process or method because Grove’s  process proceed through SN² mechanism. 

Since the associate reactant t-butyl alcohol contains three methyl group, so due to steric hindrance the back side attack on tertiary carbon atom is not possible. 

Consequently, t-butyl chloride does not prepared in Grove’s  process or method .

When tertiary alcohol is react only with concentrated HCl,t-butyl chloride is obtained. The reaction is shown below,

What is the function of anhydrous ZnCl₂ in Grove’s process ?

Anhydrous ZnCl₂ is a Lewis base. On the other hand alcohol acts as Lewis acid . So, ZnCl2 is react with alcohol to form a complex ion through which alcoholic –OH group convert into a good leaving group .

 Now the Grove’s process for preparation of chloro alkane is an example of SN2 reaction  . As a result, the SN2 reaction mechanism is easily happened.

Practice problem

• What is Grove’s  process or method ?
• What is the mechanism of Grove’s  process or method ?
• Why t-butyl chloride does not prepared in Grove’s  process or method ?
• What is the function of anhydrous ZnCl₂ in Grove’s process ?

What is Swarts reaction ?