双语化学辞典Chem Lexicon
反应 · 有机化学 · 亲电芳香取代 Organic chemistry · Electrophilic aromatic substitution

傅-克酰基化反应Friedel–Crafts acylation

拼音Pinyin fù kè xiān jī huà fǎn yìng　别名Also 弗里德尔-克拉夫茨酰基化； Friedel–Crafts acylation reaction

定义Definition

傅-克酰基化是芳烃在 AlCl₃ 等路易斯酸作用下与酰氯或酸酐反应，在芳环上引入酰基生成芳基酮的亲电取代反应。

Friedel–Crafts acylation installs an acyl group on an arene with an acyl chloride or anhydride and a Lewis acid such as AlCl₃, giving an aryl ketone by electrophilic substitution.

机理与优点Mechanism and advantages

AlCl₃ 夺取酰氯的氯，生成被共振稳定的酰基正离子 R–C≡O⁺（不重排）。芳环进攻、失去质子得芳基酮。酰基吸电子使产物钝化，不会多酰基化——这两点正好弥补了傅–克烷基化的缺陷。

AlCl₃ abstracts chloride to form a resonance-stabilised acylium ion R–C≡O⁺, which does not rearrange. Ring attack and deprotonation give the aryl ketone, whose acyl group deactivates the ring against further acylation — fixing two flaws of the alkylation.

催化剂用量Catalyst loading

产物酮的羰基与 AlCl₃ 形成稳定络合物，所以需要略多于化学计量的 AlCl₃，后处理需加水（冰酸）分解络合物。现代绿色工艺使用沸石、金属三氟甲磺酸盐或离子液体作可回收催化剂。

The ketone binds AlCl₃ strongly, so slightly more than one equivalent is needed and work-up with ice/acid breaks the complex. Greener processes use zeolites, metal triflates or ionic liquids as recyclable catalysts.

应用Applications

合成芳酮（苯乙酮、二苯甲酮）、布洛芬工业路线（BHC 法，以 HF 为催化剂和溶剂对异丁苯乙酰化）；分子内酰基化成环（如合成茚酮、四氢萘酮）；与克莱门森或沃尔夫–基斯纳还原联用制直链烷基苯。

Aryl ketones (acetophenone, benzophenone), the BHC ibuprofen route (HF-catalysed acetylation of isobutylbenzene), intramolecular cyclisations (indanones, tetralones), and straight-chain alkylbenzenes after Clemmensen or Wolff–Kishner reduction.

反应Reactions

ArH + RCOCl AlCl3⟶ ArCOR + HCl

AlCl₃（≥ 1 当量），CH₂Cl₂、CS₂ 或硝基苯，0 °C 至回流；冰盐酸后处理

AlCl₃ (≥1 equiv.) in CH₂Cl₂, CS₂ or nitrobenzene, 0 °C to reflux; ice/HCl work-up

  1. 生成酰基正离子。

    Form the acylium ion.

  2. 芳环进攻得 σ 络合物。

    Ring attack gives a σ-complex.

  3. 失去质子；产物与 AlCl₃ 络合，水解释放。

    Deprotonation; the product–AlCl₃ complex is hydrolysed.

C6H6 + CH3COCl AlCl3⟶ C6H5COCH3

制苯乙酮。

Acetophenone.

反应机理图Mechanism

红色弯箭头表示一对电子的移动方向：从电子来源（孤对电子或化学键）指向电子去向。Red curly arrows show where an electron pair moves: from its source (lone pair or bond) to its destination.

1

AlCl₃ 夺取氯，生成酰基正离子

AlCl₃ abstracts chloride to give the acylium ion

2

苯环进攻酰基正离子

The ring attacks the acylium ion

3

失去质子，恢复芳香性

Loss of H⁺ restores aromaticity

4

苯乙酮

Acetophenone

年表Timeline

  • 1877

    傅里德尔与克拉夫茨报道

    Friedel and Crafts report it

  • 1992

    BHC 布洛芬绿色工艺投产

    The green BHC ibuprofen process starts up