E2 Elimination (Dehydrohalogenation)

C2H5Br + KOH → C2H4 + KBr + H2O

Descripción general

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

Rol Sustancia Coeficiente Estado
Reactivo Potassium Hydroxide KOH 1 (aq)
Producto Ethylene C₂H₄ 1 (g)
Producto Water H₂O 1 (l)

Ejemplo cotidiano

E2 elimination is used to prepare alkenes from easily available alkyl halides and is key to understanding organic reaction selectivity.

Importancia industrial

La deshidrohalogenación se usa en la fabricación de cloruro de vinilo (a partir de dicloroetano) y en la producción de diversos alquenos para síntesis industrial.

Propiedades

Tipo
Organic
Reversible
No
Energía
Exotérmico
ΔH
-50,0 kJ/mol

Reacciones relacionadas

Epoxidation of Alkenes (mCPBA) Swern Oxidation Oxidation of Secondary Alcohol to Ketone Claisen Condensation (Ethyl Acetate) Aldol Condensation of Acetaldehyde Kolbe Electrolysis Baeyer-Villiger Oxidation Beckmann Rearrangement (Cyclohexanone Oxime) Catalytic Hydrogenation of Ethylene Dehydration of Ethanol

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.