定义Definition
脱氢反应是从分子中除去氢（通常以 H₂ 形式放出，或被氢受体接受）的反应，是氢化的逆过程，常用于由烷烃制烯烃、由醇制醛酮、由环烷烃制芳烃。
Dehydrogenation removes hydrogen from a molecule — released as H₂ or taken up by an acceptor — the reverse of hydrogenation. It converts alkanes to alkenes, alcohols to carbonyls and cycloalkanes to arenes.
热力学Thermodynamics
脱氢强烈吸热、熵增（生成气体 H₂），所以需要高温（500–650 °C）和低分压；平衡受限，常与氢受体或氧气（氧化脱氢）偶联以克服平衡限制。
Dehydrogenation is strongly endothermic with entropy gain (H₂ produced), so it needs high temperature (500–650 °C) and low partial pressure; equilibrium limits are overcome by hydrogen acceptors or oxygen (oxidative dehydrogenation).
工业应用Industrial uses
乙苯在铁系催化剂（Fe₂O₃–K₂O）上脱氢制苯乙烯；丙烷脱氢制丙烯（Pt–Sn 或 CrOₓ 催化剂）；催化重整中环己烷类脱氢成芳烃并副产氢气；乙醇经铜催化脱氢得乙醛。
Ethylbenzene → styrene over Fe₂O₃–K₂O; propane → propylene over Pt–Sn or CrOₓ; catalytic reforming converts naphthenes into aromatics with H₂ by-product; ethanol → acetaldehyde over copper.
实验室与生物体Laboratory and biology
实验室常用 DDQ、四氯苯醌、Pd/C 加热或硫、硒进行芳构化脱氢。生物体内脱氢酶以 NAD⁺、FAD 为氢受体（如乳酸 → 丙酮酸、琥珀酸 → 延胡索酸）。
In the lab DDQ, chloranil, Pd/C with heat, sulfur or selenium effect aromatisation. Biological dehydrogenases use NAD⁺ and FAD as acceptors (lactate → pyruvate, succinate → fumarate).
反应Reactions
高温（500–650 °C），Pt、Cr、Fe 氧化物等催化剂，水蒸气稀释
High temperature (500–650 °C), Pt, Cr or Fe oxide catalysts, steam dilution
C–H 键在催化剂表面活化断裂。
C–H bonds are activated on the catalyst.
β-H 消除形成双键。
β-H elimination forms the double bond.
H 原子结合为 H₂ 脱附。
H atoms recombine and desorb as H₂.
苯乙烯生产。
Styrene production.
年表Timeline
- 1930s
乙苯脱氢制苯乙烯工业化
Industrial styrene by ethylbenzene dehydrogenation
- 1949
铂重整工艺（UOP）
UOP Platforming reforming process