Hofmann Elimination
R3N(CH3)+ + OH− → alkene + R3N + H2O
Visão geral
The Hofmann elimination converts a quaternary ammonium salt to an alkene, amine, and water upon heating with base. Unlike E2 elimination, Hofmann elimination favors the less substituted alkene (anti-Zaitsev). This reaction was historically used to determine amine structures by exhaustive methylation and elimination.
Participantes
| Papel | Substância | Coeficiente | Estado |
|---|---|---|---|
| Produto | Water H₂O | 1 | (l) |
Exemplo do cotidiano
Hofmann elimination was crucial in determining the structures of complex alkaloids like morphine and quinine before modern spectroscopy.
Importância industrial
A eliminação de Hofmann é utilizada em laboratório para identificar aminas e em síntese de alcenos terminais específicos que não são acessíveis pela regra de Zaitsev.
Propriedades
- Tipo
- Organic
- Reversível
- Não
- Energia
- Exotérmico
- ΔH
- -40,0 kJ/mol
- Catalisador
- Ag₂O (for quaternary salt formation)
Reações relacionadas
Swern Oxidation
Oxidation of Secondary Alcohol to Ketone
Claisen Condensation (Ethyl Acetate)
Kolbe Electrolysis
Baeyer-Villiger Oxidation
Beckmann Rearrangement (Cyclohexanone Oxime)
Catalytic Hydrogenation of Ethylene
Condensation Polymerization (Nylon 6,6)
Cope Rearrangement
Epoxidation of Alkenes (mCPBA)
Frequently Asked Questions
What is the equation for Hofmann Elimination?
The balanced equation is: R₃N(CH₃)⁺ + OH⁻ → alkene + R₃N + H₂O.
What type of reaction is Hofmann Elimination?
Hofmann Elimination is a organic reaction.
Is Hofmann Elimination exothermic or endothermic?
Hofmann Elimination is exothermic (releases energy). The enthalpy change (ΔH) is -40.0 kJ/mol.
What conditions are needed for Hofmann Elimination?
This reaction requires a catalyst (Ag₂O (for quaternary salt formation)).