Answers to the Exercises "SN/E Competition"
If ethanol is to serve as solvent, mainly (about 80 %) reaction occurs. Due to stabilization by three alkyl substituents, the tert-butyl carbenium ion is effectively formed. Consequently, the reaction displays a unimolecular mechanism with an intermediate carbenium ion. Ethanol is a sufficient good nucleophile to react as such in an reaction. In addition, ethanol is a very weak base. Therefore, an E2 elimination through the abstraction of the β proton by a strong base in the early phase of the reaction virtually never happen.