To illustrate the SN1 mechanism for the conversion of 2-chloro-2-methylpropane in water with HCl, we begin with the structure of 2-chloro-2-methylpropane (tert-butyl chloride). In an SN1 reaction, the first step involves the ionization of the carbon-chlorine bond, leading to the formation of a tertiary carbocation and a chloride ion.
The reaction proceeds as follows:
- Formation of the Carbocation:
- The chlorine atom leaves, taking the electrons from the carbon bond with it. This generates a stable tert-butyl carbocation (C(CH3)3+).
- Nucleophilic Attack:
- Water, acting as a nucleophile, attacks the positively charged carbocation. This results in the formation of an oxonium ion (protonated alcohol).
- Deprotonation:
- The oxonium ion then loses a proton (H+) to give the final product, 2-methyl-2-propanol.
The complete reaction can be summarized as follows:
2-chloro-2-methylpropane + H2O → 2-methyl-2-propanol + HCl