The substitution reaction of cyclohexanol in the presence of diethyl ether (Et2O) and hydrochloric acid (HCl) to form chlorocyclohexane involves several steps that result in the replacement of the hydroxyl group (-OH) with a chlorine atom (-Cl).
Firstly, the HCl protonates the hydroxyl group of cyclohexanol, making it a better leaving group. This conversion results in the formation of cyclohexyl carbocation, which is more stable in this cyclic structure. The presence of diethyl ether serves as a polar aprotic solvent that stabilizes the carbocation without forming strong hydrogen bonds.
Once the carbocation is formed, a chloride ion from the HCl can then quickly react with the carbocation to produce chlorocyclohexane. This reaction is facilitated by the solvation properties of diethyl ether, which helps to stabilize the charged intermediates during the process.
In summary, the substitution mechanism involves the following key steps:
- Protonation of the hydroxyl group by HCl to form a good leaving group.
- Formation of a cyclohexyl carbocation.
- Recombination of the carbocation with a chloride ion to give chlorocyclohexane.
This overall process highlights how the solvent and acid facilitate the transformation of cyclohexanol into chlorocyclohexane through an SN1 mechanism, typical of tertiary and some secondary alcohols in acidic conditions.