Octet / Reactions
Alcohol Dehydration
Alcohol Dehydration (E1 Elimination.) Converts CC(C)(C)O to CC(C)=C using H₂SO₄, H₃PO₄. Conditions: Concentrated acid, heat.
Elimination
Reaction details
Name
Alcohol Dehydration
Type
Elimination
Subtype
E1
Starting Material
CC(C)(C)O
Product
CC(C)=C
Reagents
H₂SO₄
H₃PO₄
Conditions
Concentrated acid, heat
Temperature
> 140°C
Mechanism
- Smiles
CC(C)(C)O
- Description
Tertiary alcohol
- Smiles
CC(C)(C)[OH2+]
- Description
Protonation of OH makes water a good leaving group
- Smiles
C[C+](C)C
- Description
Water leaves, carbocation forms
- Smiles
CC(C)=C
- Description
Loss of H⁺ gives alkene
Regiochemistry
Zaitsev product (more substituted alkene)
Tips
3° alcohols dehydrate fastest
Carbocation rearrangements possible
At lower temp, substitution (ether) may compete
Related Reactions
e1-elimination
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