E2 Elimination (Dehydrohalogenation)
C2H5Br + KOH → C2H4 + KBr + H2O
Ikhtisar
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.
Peserta
| Peran | Zat | Koefisien | Keadaan |
|---|---|---|---|
| Reaktan | Potassium Hydroxide KOH | 1 | (aq) |
| Produk | Ethylene C₂H₄ | 1 | (g) |
| Produk | Water H₂O | 1 | (l) |
Contoh Sehari-hari
E2 elimination is used to prepare alkenes from easily available alkyl halides and is key to understanding organic reaction selectivity.
Pentingnya dalam Industri
Dehydrohalogenation is used in the manufacture of vinyl chloride (from ethylene dichloride) and in producing various alkene monomers.
Sifat
- Jenis
- Organic
- Dapat Dibalik
- Tidak
- Energi
- Eksoterm
- ΔH
- -50,0 kJ/mol
Reaksi Terkait
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.