Ionization followed by substitution (SN1)
In a simple SN1 pathway, slow substrate ionization forms a carbocation-containing intermediate before nucleophilic capture.
Key knowledge
In a simple SN1 pathway, slow substrate ionization forms a carbocation-containing intermediate before nucleophilic capture. When ionization controls the rate, the observed law is first order in substrate. Planar intermediates permit attack from either face, but ion pairing can prevent complete racemization.
Values and equations
r = k[RX]
- r
- ionization-controlled disappearance rate mol L⁻¹ s⁻¹
- k
- first-order coefficient s⁻¹
- [RX]
- substrate concentration mol L⁻¹
Conditions and scope
- Solvent, substrate stabilization, ion pairing and competing rearrangement/elimination matter.
- First-order kinetics alone does not prove a freely equilibrated carbocation or exact 50:50 stereochemistry.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected ionization/capture mechanism, first-order law and ion-pair qualification of racemization.
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Entry details
Permanent link to this entry ↗- Record identity
- uni-chem-sn1
- Revision
- core.1
- Structured reference record
- University core expansion