E2 Elimination (Dehydrohalogenation)

C₂H₅Br + KOH → C₂H₄ + KBr + H₂O

Tổng quan

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.

Người tham gia

Vai trò	Chất	Hệ số	Trạng thái
Chất phản ứng	Potassium Hydroxide KOH	1	(aq)
Sản phẩm	Ethylene C₂H₄	1	(g)
Sản phẩm	Water H₂O	1	(l)

Ví dụ thực tế

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

Tầm quan trọng công nghiệp

Dehydrohalogenation is used in the manufacture of vinyl chloride (from ethylene dichloride) and in producing various alkene monomers.

Tính chất

Loại: Organic
Thuận nghịch: Không
Năng lượng: Tỏa nhiệt
ΔH: -50,0 kJ/mol

Phản ứng liên quan

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.