CHEM 140A Chapter Notes - Chapter 7: Solvolysis, Deprotonation, Hydrolysis
19 Mar 2018
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Chapter 7 further reactions of haloalkanes: unimolecular substitution pathways of elimination. Secondary and tertiary halides do undergo substitution, but by another mechanism. When a substrate undergoes substitution by solvent molecules, it is called solvolysis. When the solvent is water, we say hydrolysis. Are characterized by the opposite order of reactivity. The observed rate is that of the slowest step in the sequence. The rate-determining step is the dissociation of the haloalkane to an alkyl cation and bromide. Contains positively charged central carbon atom attached to three other groups and bearing only an electron sextet. The cation is a powerful electrophile that is immediately trapped by the surrounding water. Alkyloxonium ion is the conjugate acid of an alcohol. It is a strong acid and readily deprotonated by the water in the reaction medium to furnish the final alcohol. All three steps of the mechanism of solvolysis are reversible. Large excess of nucleophilic solvent ensures complete solvolysis textbook notes page 1.
