E2 Elimination (Dehydrohalogenation)
C2H5Br + KOH → C2H4 + KBr + H2O
Visão geral
Strong base (KOH in ethanol) removes a beta-hydrogen and the halide leaves simultaneously in a concerted E2 elimination to form an alkene. The H and Br must be anti-periplanar (180 degrees) for the elimination to proceed. E2 competes with SN2, with bulky bases and secondary/tertiary substrates favoring elimination.
Participantes
| Papel | Substância | Coeficiente | Estado |
|---|---|---|---|
| Reagente | Potassium Hydroxide KOH | 1 | (aq) |
| Produto | Ethylene C₂H₄ | 1 | (g) |
| Produto | Water H₂O | 1 | (l) |
Exemplo do cotidiano
E2 elimination is used to prepare alkenes from easily available alkyl halides and is key to understanding organic reaction selectivity.
Importância industrial
A eliminação E2 é utilizada na síntese industrial de alcenos, incluindo a desidrohalogenação de cloroparafinas para produzir alcenos lineares utilizados em detergentes.
Propriedades
- Tipo
- Organic
- Reversível
- Não
- Energia
- Exotérmico
- ΔH
- -50,0 kJ/mol
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 E2 Elimination (Dehydrohalogenation)?
The balanced equation is: C₂H₅Br + KOH → C₂H₄ + KBr + H₂O.
What type of reaction is E2 Elimination (Dehydrohalogenation)?
E2 Elimination (Dehydrohalogenation) is a organic reaction.
Is E2 Elimination (Dehydrohalogenation) exothermic or endothermic?
E2 Elimination (Dehydrohalogenation) is exothermic (releases energy). The enthalpy change (ΔH) is -50.0 kJ/mol.