双语化学辞典Chem Lexicon
反应 · 有机化学 · 羧酸衍生物 Organic chemistry · Carboxylic acid derivatives

酯化反应Fischer–Speier esterification

拼音Pinyin zhǐ huà fǎn yìng　别名Also 费歇尔酯化；酸催化酯化； Fischer esterification

定义Definition

酯化反应（费歇尔–施派尔酯化）是羧酸与醇在强酸（浓硫酸等）催化下加热生成酯和水的可逆反应。

Fischer–Speier esterification is the reversible acid-catalysed (e.g. concentrated H₂SO₄) reaction of a carboxylic acid with an alcohol on heating to give an ester and water.

机理Mechanism

酸使羧酸羰基氧质子化，增强碳的亲电性；醇氧进攻得四面体中间体；质子转移后以水的形式离去；失去质子得酯。¹⁸O 标记醇的实验证明：酯中的醇氧来自醇，失去的水中的氧来自羧酸——“酸脱羟基、醇脱氢”。

Acid protonates the carbonyl oxygen; the alcohol attacks to form a tetrahedral intermediate; proton transfer lets water leave; deprotonation gives the ester. ¹⁸O-labelled alcohol shows the ester oxygen comes from the alcohol — the acid loses OH, the alcohol loses H.

平衡与产率Equilibrium and yield

乙酸与乙醇的平衡常数约为 4，等摩尔时产率约 67%。提高产率的方法：使用过量醇（或酸），或用分水器、分子筛、浓硫酸吸水除去生成的水（勒夏特列原理）。

For acetic acid and ethanol K ≈ 4, so equimolar mixtures reach ~67 %. Yields are raised by excess alcohol (or acid) or by removing water (Dean–Stark trap, sieves, H₂SO₄) — Le Chatelier.

由来与应用Origin and uses

埃米尔·费歇尔与阿图尔·施派尔于 1895 年报道。用于香料（乙酸异戊酯“香蕉油”）、溶剂（乙酸乙酯）、增塑剂、生物柴油前体和聚酯合成。中学实验：饱和碳酸钠溶液吸收乙酸乙酯中的酸和醇。

Reported by Emil Fischer and Arthur Speier in 1895; used for flavours (isoamyl acetate, ‘banana oil’), solvents (ethyl acetate), plasticisers and polyesters. In school labs saturated Na₂CO₃ removes acid and alcohol from ethyl acetate.

反应Reactions

RCOOH + R′OH ⇌ RCOOR′ + H2OH+

浓 H₂SO₄ 或 TsOH 催化，回流；过量醇或分水

Conc. H₂SO₄ or TsOH, reflux, with excess alcohol or water removal

  1. 羰基氧质子化。

    Protonation of the carbonyl oxygen.

  2. 醇亲核加成。

    Nucleophilic addition of the alcohol.

  3. 质子转移后失水。

    Proton transfer and loss of water.

  4. 去质子化得酯。

    Deprotonation gives the ester.

CH3COOH + C2H5OH ⇌ CH3COOC2H5 + H2O

制乙酸乙酯。

Ethyl acetate.

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

羰基氧质子化，羰基碳更亲电

Protonating the carbonyl O makes the carbon more electrophilic

2

乙醇进攻羰基碳

Ethanol attacks the carbonyl carbon

质子转移H⁺ shift
3

水作为离去基团离开

Water leaves

4

去质子化，催化剂再生

Deprotonation regenerates the catalyst

5

乙酸乙酯；每一步都可逆

Ethyl acetate; every step is reversible

年表Timeline

  • 1862

    贝特洛研究酯化平衡

    Berthelot studies the esterification equilibrium

  • 1895

    费歇尔与施派尔报道酸催化酯化

    Fischer and Speier report acid-catalysed esterification

  • 1938

    罗伯茨与尤里用 ¹⁸O 确定断键位置

    Roberts and Urey use ¹⁸O to locate bond cleavage